Add PDF text extraction to MCP read_file and search_files

MCP's read_file previously hard-required UTF-8 text decoding, so any
PDF in an allowed folder failed with "Cannot read file as UTF-8
text" — chat attachments already supported PDFs (raw bytes to
vision-capable models), but the AI couldn't read one on its own
during agentic file-tool use. search_files' content_search had the
same gap, silently skipping PDFs.

Adds MCPService.extractPDFText(atPath:) using PDFKit (built into
macOS, no new dependency) to pull text from a PDF's text layer.
Wired into both read_file and search_files' content search. Returns
a clear error for scanned/image-only PDFs with no text layer.
Automatically covers the Research Agents sub-agent tool loop too,
since it shares the same executeTool dispatcher.

Verified live: asked the AI to read a real PDF containing "The
secret code is PINEAPPLE-42." via read_file — it extracted the text
correctly through the MCP tool-call path.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitignore

@@ -31,6 +31,9 @@ DerivedData/
 *.dSYM.zip
 *.dSYM
 
+## Code coverage
+*.profraw
+
 ## Playgrounds
 timeline.xctimeline
 playground.xcworkspace

Package.swift

@@ -1,26 +0,0 @@
-// swift-tools-version: 6.2
-// The swift-tools-version declares the minimum version of Swift required to build this package.
-
-import PackageDescription
-
-let package = Package(
-    name: "oAI",
-    products: [
-        // Products define the executables and libraries a package produces, making them visible to other packages.
-        .library(
-            name: "oAI",
-            targets: ["oAI"]
-        ),
-    ],
-    targets: [
-        // Targets are the basic building blocks of a package, defining a module or a test suite.
-        // Targets can depend on other targets in this package and products from dependencies.
-        .target(
-            name: "oAI"
-        ),
-        .testTarget(
-            name: "oAITests",
-            dependencies: ["oAI"]
-        ),
-    ]
-)

Sources/oAI/oAI.swift

@@ -1,2 +0,0 @@
-// The Swift Programming Language
-// https://docs.swift.org/swift-book

Tests/oAITests/oAITests.swift

@@ -1,6 +0,0 @@
-import Testing
-@testable import oAI
-
-@Test func example() async throws {
-    // Write your test here and use APIs like `#expect(...)` to check expected conditions.
-}

oAI.xcodeproj/project.pbxproj

@@ -11,8 +11,19 @@
 		A550A8342F3C5C9300136F2B /* GRDB in Frameworks */ = {isa = PBXBuildFile; productRef = A550A6812F3B730000136F2B /* GRDB */; };
 /* End PBXBuildFile section */
 
+/* Begin PBXContainerItemProxy section */
+		A586FF5530122589002CFF95 /* PBXContainerItemProxy */ = {
+			isa = PBXContainerItemProxy;
+			containerPortal = A550A65A2F3B72EA00136F2B /* Project object */;
+			proxyType = 1;
+			remoteGlobalIDString = A550A6612F3B72EA00136F2B;
+			remoteInfo = oAI;
+		};
+/* End PBXContainerItemProxy section */
+
 /* Begin PBXFileReference section */
 		A550A6622F3B72EA00136F2B /* oAI.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = oAI.app; sourceTree = BUILT_PRODUCTS_DIR; };
+		A586FF5130122589002CFF95 /* oAITests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = oAITests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 /* End PBXFileReference section */
 
 /* Begin PBXFileSystemSynchronizedBuildFileExceptionSet section */
@@ -34,6 +45,11 @@
 			path = oAI;
 			sourceTree = "<group>";
 		};
+		A586FF5230122589002CFF95 /* oAITests */ = {
+			isa = PBXFileSystemSynchronizedRootGroup;
+			path = oAITests;
+			sourceTree = "<group>";
+		};
 /* End PBXFileSystemSynchronizedRootGroup section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -46,6 +62,13 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		A586FF4E30122589002CFF95 /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
@@ -53,6 +76,7 @@
 			isa = PBXGroup;
 			children = (
 				A550A6642F3B72EA00136F2B /* oAI */,
+				A586FF5230122589002CFF95 /* oAITests */,
 				A550A6632F3B72EA00136F2B /* Products */,
 			);
 			sourceTree = "<group>";
@@ -61,6 +85,7 @@
 			isa = PBXGroup;
 			children = (
 				A550A6622F3B72EA00136F2B /* oAI.app */,
+				A586FF5130122589002CFF95 /* oAITests.xctest */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -92,6 +117,29 @@
 			productReference = A550A6622F3B72EA00136F2B /* oAI.app */;
 			productType = "com.apple.product-type.application";
 		};
+		A586FF5030122589002CFF95 /* oAITests */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = A586FF5930122589002CFF95 /* Build configuration list for PBXNativeTarget "oAITests" */;
+			buildPhases = (
+				A586FF4D30122589002CFF95 /* Sources */,
+				A586FF4E30122589002CFF95 /* Frameworks */,
+				A586FF4F30122589002CFF95 /* Resources */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+				A586FF5630122589002CFF95 /* PBXTargetDependency */,
+			);
+			fileSystemSynchronizedGroups = (
+				A586FF5230122589002CFF95 /* oAITests */,
+			);
+			name = oAITests;
+			packageProductDependencies = (
+			);
+			productName = oAITests;
+			productReference = A586FF5130122589002CFF95 /* oAITests.xctest */;
+			productType = "com.apple.product-type.bundle.unit-test";
+		};
 /* End PBXNativeTarget section */
 
 /* Begin PBXProject section */
@@ -99,12 +147,16 @@
 			isa = PBXProject;
 			attributes = {
 				BuildIndependentTargetsInParallel = 1;
-				LastSwiftUpdateCheck = 2620;
+				LastSwiftUpdateCheck = 2700;
-				LastUpgradeCheck = 2620;
+				LastUpgradeCheck = 2700;
 				TargetAttributes = {
 					A550A6612F3B72EA00136F2B = {
 						CreatedOnToolsVersion = 26.2;
 					};
+					A586FF5030122589002CFF95 = {
+						CreatedOnToolsVersion = 27.0;
+						TestTargetID = A550A6612F3B72EA00136F2B;
+					};
 				};
 			};
 			buildConfigurationList = A550A65D2F3B72EA00136F2B /* Build configuration list for PBXProject "oAI" */;
@@ -131,6 +183,7 @@
 			projectRoot = "";
 			targets = (
 				A550A6612F3B72EA00136F2B /* oAI */,
+				A586FF5030122589002CFF95 /* oAITests */,
 			);
 		};
 /* End PBXProject section */
@@ -143,6 +196,13 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		A586FF4F30122589002CFF95 /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXResourcesBuildPhase section */
 
 /* Begin PBXSourcesBuildPhase section */
@@ -153,14 +213,30 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		A586FF4D30122589002CFF95 /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXSourcesBuildPhase section */
 
+/* Begin PBXTargetDependency section */
+		A586FF5630122589002CFF95 /* PBXTargetDependency */ = {
+			isa = PBXTargetDependency;
+			target = A550A6612F3B72EA00136F2B /* oAI */;
+			targetProxy = A586FF5530122589002CFF95 /* PBXContainerItemProxy */;
+		};
+/* End PBXTargetDependency section */
+
 /* Begin XCBuildConfiguration section */
 		A550A66B2F3B72EC00136F2B /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS = YES;
+				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++20";
@@ -190,7 +266,9 @@
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = NO;
+				DEAD_CODE_STRIPPING = YES;
 				DEBUG_INFORMATION_FORMAT = dwarf;
+				DEVELOPMENT_TEAM = 6RJQ2QZYPG;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
 				ENABLE_USER_SCRIPT_SANDBOXING = YES;
@@ -212,6 +290,7 @@
 				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
 				MTL_FAST_MATH = YES;
 				ONLY_ACTIVE_ARCH = YES;
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = "DEBUG $(inherited)";
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
 			};
@@ -222,6 +301,7 @@
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS = YES;
+				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++20";
@@ -251,7 +331,9 @@
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = NO;
+				DEAD_CODE_STRIPPING = YES;
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
+				DEVELOPMENT_TEAM = 6RJQ2QZYPG;
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_USER_SCRIPT_SANDBOXING = YES;
@@ -266,6 +348,7 @@
 				LOCALIZATION_PREFERS_STRING_CATALOGS = YES;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				MTL_FAST_MATH = YES;
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
 				SWIFT_COMPILATION_MODE = wholemodule;
 			};
 			name = Release;
@@ -278,12 +361,12 @@
 				CODE_SIGN_ENTITLEMENTS = oAI/oAI.entitlements;
 				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = 1;
-				DEVELOPMENT_TEAM = 6RJQ2QZYPG;
+				DEAD_CODE_STRIPPING = YES;
 				ENABLE_APP_SANDBOX = NO;
 				ENABLE_PREVIEWS = YES;
 				ENABLE_USER_SELECTED_FILES = readonly;
 				GENERATE_INFOPLIST_FILE = YES;
-				INFOPLIST_FILE = "oAI/Info.plist";
+				INFOPLIST_FILE = oAI/Info.plist;
 				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.utilities";
 				INFOPLIST_KEY_NSCalendarsFullAccessUsageDescription = "oAI can read and create calendar events when you ask it to, if you enable Calendar access in Settings.";
 				INFOPLIST_KEY_NSContactsUsageDescription = "oAI can search your contacts when you ask it to, if you enable Contacts access in Settings.";
@@ -328,12 +411,12 @@
 				CODE_SIGN_ENTITLEMENTS = oAI/oAI.entitlements;
 				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = 1;
-				DEVELOPMENT_TEAM = 6RJQ2QZYPG;
+				DEAD_CODE_STRIPPING = YES;
 				ENABLE_APP_SANDBOX = NO;
 				ENABLE_PREVIEWS = YES;
 				ENABLE_USER_SELECTED_FILES = readonly;
 				GENERATE_INFOPLIST_FILE = YES;
-				INFOPLIST_FILE = "oAI/Info.plist";
+				INFOPLIST_FILE = oAI/Info.plist;
 				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.utilities";
 				INFOPLIST_KEY_NSCalendarsFullAccessUsageDescription = "oAI can read and create calendar events when you ask it to, if you enable Calendar access in Settings.";
 				INFOPLIST_KEY_NSContactsUsageDescription = "oAI can search your contacts when you ask it to, if you enable Contacts access in Settings.";
@@ -370,6 +453,50 @@
 			};
 			name = Release;
 		};
+		A586FF5730122589002CFF95 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				BUNDLE_LOADER = "$(TEST_HOST)";
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEAD_CODE_STRIPPING = YES;
+				GENERATE_INFOPLIST_FILE = YES;
+				MACOSX_DEPLOYMENT_TARGET = 27.0;
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = com.oai.oAITests;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SDKROOT = macosx;
+				STRING_CATALOG_GENERATE_SYMBOLS = NO;
+				SWIFT_APPROACHABLE_CONCURRENCY = YES;
+				SWIFT_EMIT_LOC_STRINGS = NO;
+				SWIFT_UPCOMING_FEATURE_MEMBER_IMPORT_VISIBILITY = YES;
+				SWIFT_VERSION = 5.0;
+				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/oAI.app/$(BUNDLE_EXECUTABLE_FOLDER_PATH)/oAI";
+			};
+			name = Debug;
+		};
+		A586FF5830122589002CFF95 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				BUNDLE_LOADER = "$(TEST_HOST)";
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEAD_CODE_STRIPPING = YES;
+				GENERATE_INFOPLIST_FILE = YES;
+				MACOSX_DEPLOYMENT_TARGET = 27.0;
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = com.oai.oAITests;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SDKROOT = macosx;
+				STRING_CATALOG_GENERATE_SYMBOLS = NO;
+				SWIFT_APPROACHABLE_CONCURRENCY = YES;
+				SWIFT_EMIT_LOC_STRINGS = NO;
+				SWIFT_UPCOMING_FEATURE_MEMBER_IMPORT_VISIBILITY = YES;
+				SWIFT_VERSION = 5.0;
+				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/oAI.app/$(BUNDLE_EXECUTABLE_FOLDER_PATH)/oAI";
+			};
+			name = Release;
+		};
 /* End XCBuildConfiguration section */
 
 /* Begin XCConfigurationList section */
@@ -391,6 +518,15 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
+		A586FF5930122589002CFF95 /* Build configuration list for PBXNativeTarget "oAITests" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				A586FF5730122589002CFF95 /* Debug */,
+				A586FF5830122589002CFF95 /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
 /* End XCConfigurationList section */
 
 /* Begin XCRemoteSwiftPackageReference section */

oAI/Models/Settings.swift

@@ -56,9 +56,13 @@ struct Settings: Codable {
         case anthropic
         case openai
         case ollama
+        case appleOnDevice = "apple_on_device"
 
         var displayName: String {
-            rawValue.capitalized
+            switch self {
+            case .appleOnDevice: return "Apple Intelligence"
+            default: return rawValue.capitalized
+            }
         }
 
         var iconName: String {
@@ -67,6 +71,7 @@ struct Settings: Codable {
             case .anthropic: return "brain"
             case .openai: return "sparkles"
             case .ollama: return "server.rack"
+            case .appleOnDevice: return "apple.logo"
             }
         }
     }

oAI/Providers/AnthropicProvider.swift

@@ -186,6 +186,21 @@ class AnthropicProvider: AIProvider {
         ("claude-haiku",   0.80, 4.0),
     ]
 
+    /// Fuzzy pricing lookup for a model ID not found in `knownModels`: finds the
+    /// longest matching prefix in `fallback` (longest match wins when several
+    /// prefixes match, e.g. a future "claude-sonnet-mini" against both
+    /// "claude-sonnet" and a shorter unrelated prefix). Unmatched IDs price at zero.
+    static func resolveFallbackPricing(
+        for modelId: String,
+        fallback: [(prefix: String, prompt: Double, completion: Double)] = pricingFallback
+    ) -> ModelInfo.Pricing {
+        let match = fallback
+            .filter { modelId.hasPrefix($0.prefix) }
+            .max(by: { $0.prefix.count < $1.prefix.count })
+        return match.map { ModelInfo.Pricing(prompt: $0.prompt, completion: $0.completion) }
+            ?? ModelInfo.Pricing(prompt: 0, completion: 0)
+    }
+
     /// Fetch live model list from GET /v1/models, enriched with local pricing/context metadata.
     /// Falls back to knownModels if the request fails (no key, offline, etc.).
     func listModels() async throws -> [ModelInfo] {
@@ -223,11 +238,7 @@ class AnthropicProvider: AIProvider {
                 // Exact match first
                 if let known = enrichment[id] { return known }
                 // Fuzzy fallback: find the longest prefix that matches
-                let fallback = Self.pricingFallback
+                let pricing = Self.resolveFallbackPricing(for: id)
-                    .filter { id.hasPrefix($0.prefix) }
-                    .max(by: { $0.prefix.count < $1.prefix.count })
-                let pricing = fallback.map { ModelInfo.Pricing(prompt: $0.prompt, completion: $0.completion) }
-                    ?? ModelInfo.Pricing(prompt: 0, completion: 0)
                 return ModelInfo(
                     id: id,
                     name: displayName,
@@ -571,7 +582,7 @@ class AnthropicProvider: AIProvider {
 
     // MARK: - Request Building
 
-    private func buildURLRequest(from request: ChatRequest, stream: Bool) throws -> (URLRequest, Data) {
+    func buildURLRequest(from request: ChatRequest, stream: Bool) throws -> (URLRequest, Data) {
         let url = messagesURL
 
         // Separate system message
@@ -685,7 +696,7 @@ class AnthropicProvider: AIProvider {
         return (urlRequest, bodyData)
     }
 
-    private func parseResponse(data: Data) throws -> ChatResponse {
+    func parseResponse(data: Data) throws -> ChatResponse {
         guard let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
             throw ProviderError.invalidResponse
         }
@@ -741,7 +752,7 @@ class AnthropicProvider: AIProvider {
         )
     }
 
-    private func convertParametersToDict(_ params: Tool.Function.Parameters) -> [String: Any] {
+    func convertParametersToDict(_ params: Tool.Function.Parameters) -> [String: Any] {
         var props: [String: Any] = [:]
         for (key, prop) in params.properties {
             var propDict: [String: Any] = [

oAI/Providers/AppleFoundationProvider.swift

@@ -0,0 +1,228 @@
+//
+//  AppleFoundationProvider.swift
+//  oAI
+//
+//  Apple Foundation Models provider (on-device Apple Intelligence)
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+//
+// This file is part of oAI.
+//
+// oAI is licensed under the PolyForm Noncommercial License 1.0.0.
+// You may use, study, modify, and share it for any noncommercial
+// purpose. Commercial use — including selling oAI or any part of
+// it, standalone or bundled into another product or service —
+// requires a separate commercial license from the copyright holder.
+//
+// See the LICENSE file or
+// <https://polyformproject.org/licenses/noncommercial/1.0.0> for
+// the full license text. For commercial licensing, contact Rune
+// Olsen via <https://oai.pm>.
+
+
+import Foundation
+import FoundationModels
+import os
+
+final class AppleFoundationProvider: AIProvider {
+    let name = "Apple Intelligence"
+
+    let capabilities = ProviderCapabilities(
+        supportsStreaming: true,
+        supportsVision: false,
+        supportsTools: false,
+        supportsOnlineSearch: false,
+        maxContextLength: 4096
+    )
+
+    // MARK: - Models
+
+    func listModels() async throws -> [ModelInfo] {
+        [
+            ModelInfo(
+                id: "apple-on-device",
+                name: "Apple On-Device (Beta)",
+                description: "On-device Apple Intelligence model. Private, free, and works offline. 4K context window. Apple's Foundation Models framework is still in active beta (currently macOS 27 beta) — expect occasional generation errors and rough edges.",
+                contextLength: 4096,
+                pricing: ModelInfo.Pricing(prompt: 0, completion: 0),
+                capabilities: ModelInfo.ModelCapabilities(
+                    vision: false,
+                    tools: false,
+                    online: false
+                )
+            )
+        ]
+    }
+
+    func getModel(_ id: String) async throws -> ModelInfo? {
+        try await listModels().first { $0.id == id }
+    }
+
+    func getCredits() async throws -> Credits? { nil }
+
+    // MARK: - Streaming chat
+
+    func streamChat(request: ChatRequest) -> AsyncThrowingStream<StreamChunk, Error> {
+        AsyncThrowingStream { continuation in
+            Task {
+                do {
+                    let session = try self.makeSession(for: request)
+                    let prompt = self.lastUserMessage(from: request)
+
+                    // streamResponse(to: String) → ResponseStream<String>
+                    // Each snapshot.content is the full accumulated text so far (snapshot model).
+                    // We compute deltas by comparing each snapshot to the previous.
+                    let stream = session.streamResponse(to: prompt)
+                    var lastContent = ""
+
+                    for try await snapshot in stream {
+                        let current = snapshot.content
+                        if current.count > lastContent.count {
+                            let delta = String(current.dropFirst(lastContent.count))
+                            continuation.yield(StreamChunk(
+                                id: UUID().uuidString,
+                                model: request.model,
+                                delta: StreamChunk.Delta(content: delta, role: "assistant"),
+                                finishReason: nil,
+                                usage: nil
+                            ))
+                            lastContent = current
+                        }
+                    }
+
+                    continuation.yield(StreamChunk(
+                        id: UUID().uuidString,
+                        model: request.model,
+                        delta: StreamChunk.Delta(content: nil, role: nil),
+                        finishReason: "stop",
+                        usage: nil
+                    ))
+                    continuation.finish()
+
+                } catch {
+                    continuation.finish(throwing: self.mapProviderError(error))
+                }
+            }
+        }
+    }
+
+    // MARK: - Non-streaming chat
+
+    func chat(request: ChatRequest) async throws -> ChatResponse {
+        let session = try makeSession(for: request)
+        let prompt = lastUserMessage(from: request)
+        do {
+            let response: LanguageModelSession.Response<String> = try await session.respond(to: prompt)
+            return ChatResponse(
+                id: UUID().uuidString,
+                model: request.model,
+                content: response.content,
+                role: "assistant",
+                finishReason: "stop",
+                usage: nil,
+                created: Date()
+            )
+        } catch {
+            throw mapProviderError(error)
+        }
+    }
+
+    // MARK: - Tool messages (not supported in Phase 1)
+
+    func chatWithToolMessages(model: String, messages: [[String: Any]], tools: [Tool]?, maxTokens: Int?, temperature: Double?) async throws -> ChatResponse {
+        throw ProviderError.unknown("Tool calling requires Apple Foundation Models Phase 3.")
+    }
+
+    // MARK: - Session construction
+
+    private func makeSession(for request: ChatRequest) throws -> LanguageModelSession {
+        guard case .available = SystemLanguageModel.default.availability else {
+            throw availabilityError()
+        }
+
+        // Build instructions: system prompt + prior conversation turns as formatted text.
+        // Foundation Models sessions don't accept a message array — we inject history inline.
+        var instructions = request.systemPrompt ?? ""
+        let priorMessages = request.messages.dropLast().filter { $0.role != .system }
+
+        if !priorMessages.isEmpty {
+            let history = priorMessages
+                .map { m -> String in
+                    let label = m.role == .user ? "User" : "Assistant"
+                    return "\(label): \(m.content)"
+                }
+                .joined(separator: "\n")
+            instructions += "\n\nConversation so far:\n\(history)\n\nContinue from here."
+        }
+
+        return instructions.isEmpty
+            ? LanguageModelSession()
+            : LanguageModelSession(instructions: instructions)
+    }
+
+    private func lastUserMessage(from request: ChatRequest) -> String {
+        request.messages.last(where: { $0.role == .user })?.content ?? ""
+    }
+
+    // MARK: - Error mapping
+
+    private func availabilityError() -> Error {
+        switch SystemLanguageModel.default.availability {
+        case .unavailable(.deviceNotEligible):
+            return ProviderError.unknown("This Mac doesn't support Apple Intelligence. Apple Silicon is required.")
+        case .unavailable(.appleIntelligenceNotEnabled):
+            return ProviderError.unknown("Apple Intelligence is not enabled. Open System Settings → Apple Intelligence to turn it on.")
+        case .unavailable(.modelNotReady):
+            return ProviderError.unknown("Apple Intelligence model is still downloading. Please wait and try again.")
+        default:
+            return ProviderError.unknown("Apple Intelligence is not available on this device.")
+        }
+    }
+
+    /// Dispatches to whichever generation-error type the running OS actually throws.
+    /// `LanguageModelSession.GenerationError` was deprecated in macOS 27.0 in favor of the new
+    /// top-level `LanguageModelError` — on a macOS 27+ runtime, generation failures come through
+    /// as `LanguageModelError`, not `GenerationError`, even though the app's deployment target
+    /// (26.2) still needs to handle macOS 26.x runtimes throwing the older type.
+    private func mapProviderError(_ error: Error) -> Error {
+        if #available(macOS 27.0, *), let lmError = error as? LanguageModelError {
+            return mapLanguageModelError(lmError)
+        }
+        if let genError = error as? LanguageModelSession.GenerationError {
+            return mapGenerationError(genError)
+        }
+        return error
+    }
+
+    @available(macOS 27.0, *)
+    private func mapLanguageModelError(_ error: LanguageModelError) -> Error {
+        switch error {
+        case .contextSizeExceeded(let detail):
+            return ProviderError.unknown("Apple Intelligence context limit exceeded (\(detail.tokenCount)/\(detail.contextSize) tokens). Start a new chat or enable Progressive Summarization in Settings → Advanced.")
+        case .rateLimited:
+            return ProviderError.rateLimitExceeded
+        case .guardrailViolation:
+            return ProviderError.unknown("Apple Intelligence declined to respond to this message.")
+        case .timeout:
+            return ProviderError.timeout
+        default:
+            return error
+        }
+    }
+
+    /// macOS 26.x fallback — `GenerationError` is deprecated on macOS 27+ but still the type
+    /// actually thrown on 26.x runtimes, which the 26.2 deployment target must keep supporting.
+    private func mapGenerationError(_ error: LanguageModelSession.GenerationError) -> Error {
+        switch error {
+        case .exceededContextWindowSize:
+            return ProviderError.unknown("Apple Intelligence context limit exceeded (4,096 tokens). Start a new chat or enable Progressive Summarization in Settings → Advanced.")
+        case .rateLimited:
+            return ProviderError.rateLimitExceeded
+        case .guardrailViolation:
+            return ProviderError.unknown("Apple Intelligence declined to respond to this message.")
+        default:
+            return error
+        }
+    }
+}

oAI/Providers/OllamaProvider.swift

@@ -275,7 +275,7 @@ class OllamaProvider: AIProvider {
 
     // MARK: - Helpers
 
-    private func buildRequestBody(from request: ChatRequest, stream: Bool) -> [String: Any] {
+    func buildRequestBody(from request: ChatRequest, stream: Bool) -> [String: Any] {
         var messages: [[String: Any]] = []
 
         // Add system prompt as a system message
@@ -301,7 +301,7 @@ class OllamaProvider: AIProvider {
         return body
     }
 
-    private func parseOllamaResponse(_ json: [String: Any], model: String) -> ChatResponse {
+    func parseOllamaResponse(_ json: [String: Any], model: String) -> ChatResponse {
         let message = json["message"] as? [String: Any]
         let content = message?["content"] as? String ?? ""
         let promptTokens = json["prompt_eval_count"] as? Int ?? 0

oAI/Providers/OpenAIProvider.swift

@@ -117,7 +117,7 @@ class OpenAIProvider: AIProvider {
         }
     }
 
-    private func fallbackModels() -> [ModelInfo] {
+    func fallbackModels() -> [ModelInfo] {
         Self.knownModels.map { id, info in
             ModelInfo(
                 id: id,
@@ -283,7 +283,7 @@ class OpenAIProvider: AIProvider {
 
     // MARK: - Helpers
 
-    private func buildURLRequest(from request: ChatRequest, stream: Bool) throws -> URLRequest {
+    func buildURLRequest(from request: ChatRequest, stream: Bool) throws -> URLRequest {
         let url = URL(string: "\(baseURL)/chat/completions")!
 
         var apiMessages: [[String: Any]] = []
@@ -358,7 +358,7 @@ class OpenAIProvider: AIProvider {
         return urlRequest
     }
 
-    private func convertToChatResponse(_ apiResponse: OpenRouterChatResponse) -> ChatResponse {
+    func convertToChatResponse(_ apiResponse: OpenRouterChatResponse) -> ChatResponse {
         guard let choice = apiResponse.choices.first else {
             return ChatResponse(id: apiResponse.id, model: apiResponse.model, content: "", role: "assistant", finishReason: nil, usage: nil, created: Date())
         }

oAI/Providers/OpenRouterProvider.swift

@@ -416,7 +416,7 @@ class OpenRouterProvider: AIProvider {
     
     // MARK: - Helper Methods
     
-    private func buildAPIRequest(from request: ChatRequest) throws -> OpenRouterChatRequest {
+    func buildAPIRequest(from request: ChatRequest) throws -> OpenRouterChatRequest {
         let apiMessages = request.messages.map { message -> OpenRouterChatRequest.APIMessage in
 
             let hasAttachments = message.attachments?.contains(where: { $0.data != nil }) ?? false
@@ -500,7 +500,7 @@ class OpenRouterProvider: AIProvider {
         )
     }
     
-    private func convertToChatResponse(_ apiResponse: OpenRouterChatResponse) throws -> ChatResponse {
+    func convertToChatResponse(_ apiResponse: OpenRouterChatResponse) throws -> ChatResponse {
         guard let choice = apiResponse.choices.first else {
             throw ProviderError.invalidResponse
         }
@@ -540,7 +540,7 @@ class OpenRouterProvider: AIProvider {
         )
     }
 
-    private func convertToStreamChunk(_ apiChunk: OpenRouterStreamChunk) throws -> StreamChunk {
+    func convertToStreamChunk(_ apiChunk: OpenRouterStreamChunk) throws -> StreamChunk {
         guard let choice = apiChunk.choices.first else {
             throw ProviderError.invalidResponse
         }
@@ -579,7 +579,7 @@ class OpenRouterProvider: AIProvider {
     }
 
     /// Decode base64 data URL images from API response
-    private func decodeImageOutputs(_ outputs: [OpenRouterChatResponse.ImageOutput]) -> [Data]? {
+    func decodeImageOutputs(_ outputs: [OpenRouterChatResponse.ImageOutput]) -> [Data]? {
         let decoded = outputs.compactMap { output -> Data? in
             let url = output.imageUrl.url
             // Strip "data:image/...;base64," prefix

oAI/Providers/ProviderRegistry.swift

@@ -67,6 +67,9 @@ class ProviderRegistry {
 
         case .ollama:
             provider = OllamaProvider(baseURL: settings.ollamaEffectiveURL)
+
+        case .appleOnDevice:
+            provider = AppleFoundationProvider()
         }
         
         // Cache and return
@@ -104,6 +107,8 @@ class ProviderRegistry {
             return settings.openaiAPIKey != nil && !settings.openaiAPIKey!.isEmpty
         case .ollama:
             return settings.ollamaConfigured
+        case .appleOnDevice:
+            return true  // no API key needed
         }
     }
 

oAI/Services/BackupService.swift

@@ -206,37 +206,68 @@ final class BackupService {
         log.debug("Pushed \(payload.ids.count) favorite model(s) to iCloud")
     }
 
+    /// Outcome of reconciling local favorites against the iCloud copy. Pure result type --
+    /// see `decideFavoritesSync` for the actual decision logic.
+    enum FavoritesSyncDecision: Equatable {
+        case applyRemote(ids: Set<String>, updatedAt: String)
+        case pushLocal
+        case mergeAndPush(ids: Set<String>, updatedAt: String)
+        case noop
+    }
+
+    /// Last-write-wins reconciliation, pulled out of `syncFavoritesOnLaunch` so the branching
+    /// logic (5 cases: remote absent / remote newer / local newer / tied-but-different /
+    /// tied-and-identical) can be tested without touching iCloud Drive or SettingsService.
+    static func decideFavoritesSync(
+        localIds: Set<String>,
+        localUpdatedAt: String,
+        remote: FavoritesPayload?,
+        now: Date
+    ) -> FavoritesSyncDecision {
+        guard let remote else {
+            return .pushLocal
+        }
+        if remote.updatedAt > localUpdatedAt {
+            return .applyRemote(ids: Set(remote.ids), updatedAt: remote.updatedAt)
+        } else if localUpdatedAt > remote.updatedAt {
+            return .pushLocal
+        } else if Set(remote.ids) != localIds {
+            // Tied timestamps (both empty is the common case: two machines that already had
+            // favorites before this sync feature existed, neither ever bumped the timestamp).
+            // Union rather than silently dropping one side's favorites.
+            let merged = localIds.union(remote.ids)
+            return .mergeAndPush(ids: merged, updatedAt: ISO8601DateFormatter().string(from: now))
+        }
+        return .noop
+    }
+
     /// Reconcile local favorites with the iCloud copy using last-write-wins (by timestamp).
     /// Call on launch (and optionally on app-become-active) to pick up changes from other machines.
     func syncFavoritesOnLaunch() async {
         let settings = SettingsService.shared
         let fileURL = favoritesFileURL()
 
-        guard let data = try? Data(contentsOf: fileURL),
+        let remote: FavoritesPayload? = {
-              let remote = try? JSONDecoder().decode(FavoritesPayload.self, from: data) else {
+            guard let data = try? Data(contentsOf: fileURL) else { return nil }
-            // No remote copy yet — push local state (may be empty, that's fine).
+            return try? JSONDecoder().decode(FavoritesPayload.self, from: data)
-            await pushFavorites()
+        }()
-            return
-        }
-
-        let localUpdatedAt = settings.favoriteModelsUpdatedAt
         let localIds = settings.favoriteModelIds
-        if remote.updatedAt > localUpdatedAt {
+
-            settings.favoriteModelIds = Set(remote.ids)
+        switch Self.decideFavoritesSync(localIds: localIds, localUpdatedAt: settings.favoriteModelsUpdatedAt, remote: remote, now: Date()) {
-            settings.favoriteModelsUpdatedAt = remote.updatedAt
+        case .pushLocal:
-            log.info("Applied \(remote.ids.count) favorite model(s) from iCloud (remote was newer)")
-        } else if localUpdatedAt > remote.updatedAt {
             await pushFavorites()
-        } else if Set(remote.ids) != localIds {
+        case .applyRemote(let ids, let updatedAt):
-            // Tied timestamps (both empty is the common case: two machines that already had
+            settings.favoriteModelIds = ids
-            // favorites before this sync feature existed, neither ever bumped the timestamp).
+            settings.favoriteModelsUpdatedAt = updatedAt
-            // Union rather than silently dropping one side's favorites.
+            log.info("Applied \(ids.count) favorite model(s) from iCloud (remote was newer)")
-            settings.favoriteModelIds = localIds.union(remote.ids)
+        case .mergeAndPush(let ids, let updatedAt):
-            settings.favoriteModelsUpdatedAt = ISO8601DateFormatter().string(from: Date())
+            settings.favoriteModelIds = ids
+            settings.favoriteModelsUpdatedAt = updatedAt
             await pushFavorites()
-            log.info("Merged favorites from iCloud (tied timestamps) — union of \(localIds.count) local + \(remote.ids.count) remote")
+            log.info("Merged favorites from iCloud (tied timestamps) — union of \(localIds.count) local + \(remote?.ids.count ?? 0) remote")
+        case .noop:
+            break
         }
-        // Equal timestamps and identical sets: already in sync, nothing to do.
     }
 
     // MARK: - Automatic Backup
@@ -252,17 +283,27 @@ final class BackupService {
         }
     }
 
-    func checkAndPerformAutoBackupIfDue() async {
+    /// Whether an automatic backup should run now, given the chosen frequency and the last
-        let frequency = SettingsService.shared.autoBackupFrequency
+    /// known backup time. Pulled out of `checkAndPerformAutoBackupIfDue` for testability --
+    /// "manual" is never due, a missing last-backup-date is always due, otherwise it's due
+    /// once the elapsed time reaches the frequency's interval.
+    static func isBackupDue(frequency: String, lastBackupDate: Date?, now: Date) -> Bool {
         let interval: TimeInterval
         switch frequency {
-        case "daily": interval = Self.dailyInterval
+        case "daily": interval = dailyInterval
-        case "weekly": interval = Self.weeklyInterval
+        case "weekly": interval = weeklyInterval
-        default: return // "manual" — user triggers backups by hand
+        default: return false // "manual" — user triggers backups by hand
         }
+        guard let last = lastBackupDate else { return true }
+        return now.timeIntervalSince(last) >= interval
+    }
+
+    func checkAndPerformAutoBackupIfDue() async {
+        let frequency = SettingsService.shared.autoBackupFrequency
+        guard frequency == "daily" || frequency == "weekly" else { return }
 
         checkForExistingBackup()
-        if let last = lastBackupDate, Date().timeIntervalSince(last) < interval {
+        guard Self.isBackupDue(frequency: frequency, lastBackupDate: lastBackupDate, now: Date()) else {
             return // not due yet
         }
 

oAI/Services/ContextSelectionService.swift

@@ -47,7 +47,12 @@ enum SelectionStrategy {
 final class ContextSelectionService {
     static let shared = ContextSelectionService()
 
-    private init() {}
+    private let db: DatabaseService
+
+    /// `db` defaults to the shared on-disk instance; tests inject an in-memory `DatabaseService`.
+    init(db: DatabaseService = .shared) {
+        self.db = db
+    }
 
     /// Select context messages using the specified strategy
     func selectContext(
@@ -98,7 +103,7 @@ final class ContextSelectionService {
 
     // MARK: - Smart Selection Algorithm
 
-    private func smartSelection(allMessages: [Message], maxTokens: Int, conversationId: UUID? = nil) -> ContextWindow {
+    func smartSelection(allMessages: [Message], maxTokens: Int, conversationId: UUID? = nil) -> ContextWindow {
         guard !allMessages.isEmpty else {
             return ContextWindow(messages: [], summaries: [], totalTokens: 0, excludedCount: 0)
         }
@@ -191,12 +196,12 @@ final class ContextSelectionService {
     }
 
     /// Get summaries for excluded message ranges
-    private func getSummariesForExcludedRange(
+    func getSummariesForExcludedRange(
         conversationId: UUID,
         totalMessages: Int,
         selectedCount: Int
     ) -> [String] {
-        guard let summaryRecords = try? DatabaseService.shared.getConversationSummaries(conversationId: conversationId) else {
+        guard let summaryRecords = try? db.getConversationSummaries(conversationId: conversationId) else {
             return []
         }
 
@@ -214,7 +219,7 @@ final class ContextSelectionService {
     // MARK: - Importance Scoring
 
     /// Calculate importance score (0.0 - 1.0) for a message
-    private func getImportanceScore(_ message: Message) -> Double {
+    func getImportanceScore(_ message: Message) -> Double {
         var score = 0.0
 
         // Factor 1: Cost (expensive calls are important)
@@ -238,8 +243,8 @@ final class ContextSelectionService {
     }
 
     /// Check if a message is starred by the user
-    private func isMessageStarred(_ message: Message) -> Bool {
+    func isMessageStarred(_ message: Message) -> Bool {
-        guard let metadata = try? DatabaseService.shared.getMessageMetadata(messageId: message.id) else {
+        guard let metadata = try? db.getMessageMetadata(messageId: message.id) else {
             return false
         }
         return metadata.user_starred == 1
@@ -248,7 +253,7 @@ final class ContextSelectionService {
     // MARK: - Token Estimation
 
     /// Estimate token count for messages (rough approximation)
-    private func estimateTokens(_ messages: [Message]) -> Int {
+    func estimateTokens(_ messages: [Message]) -> Int {
         var total = 0
         for message in messages {
             if let tokens = message.tokens {

oAI/Services/DatabaseService.swift

@@ -154,7 +154,14 @@ final class DatabaseService: Sendable {
         (try? isoStyle.parse(string)) ?? (try? Date(string, strategy: .iso8601))
     }
 
-    nonisolated private init() {
+    /// Test seam: build a DatabaseService around a caller-provided queue (e.g. an in-memory `DatabaseQueue()`).
+    /// Each test should create its own fresh instance — never mutate `.shared` from a test.
+    nonisolated init(dbQueue: DatabaseQueue) {
+        self.dbQueue = dbQueue
+        try! migrator.migrate(dbQueue)
+    }
+
+    nonisolated private convenience init() {
         let fileManager = FileManager.default
         let appSupport = fileManager.urls(for: .applicationSupportDirectory, in: .userDomainMask).first!
         let dbDirectory = appSupport.appendingPathComponent("oAI", isDirectory: true)
@@ -163,12 +170,25 @@ final class DatabaseService: Sendable {
 
         let dbPath = dbDirectory.appendingPathComponent("oai_conversations.db").path
         Log.db.info("Opening database at \(dbPath)")
-        dbQueue = try! DatabaseQueue(path: dbPath)
+        self.init(dbQueue: try! DatabaseQueue(path: dbPath))
-
-        try! migrator.migrate(dbQueue)
     }
 
-    private nonisolated var migrator: DatabaseMigrator {
+    /// Test seam: a throwaway in-memory instance with all migrations applied. Avoids requiring
+    /// `import GRDB` from the test target just to construct a `DatabaseQueue()`.
+    nonisolated static func makeInMemory() -> DatabaseService {
+        DatabaseService(dbQueue: try! DatabaseQueue())
+    }
+
+    /// Test seam: schema introspection, so migration tests don't need `import GRDB` either.
+    nonisolated func tableExists(_ name: String) -> Bool {
+        (try? dbQueue.read { db in try db.tableExists(name) }) ?? false
+    }
+
+    nonisolated func columnNames(in table: String) -> [String] {
+        (try? dbQueue.read { db in try db.columns(in: table).map(\.name) }) ?? []
+    }
+
+    nonisolated var migrator: DatabaseMigrator {
         var migrator = DatabaseMigrator()
 
         migrator.registerMigration("v1") { db in

oAI/Services/EmbeddingService.swift

@@ -348,7 +348,7 @@ final class EmbeddingService {
     // MARK: - Serialization
 
     /// Serialize embedding to binary data (4 bytes per float, little-endian)
-    private func serializeEmbedding(_ embedding: [Float]) -> Data {
+    nonisolated func serializeEmbedding(_ embedding: [Float]) -> Data {
         var data = Data(capacity: embedding.count * 4)
         for value in embedding {
             var littleEndian = value.bitPattern.littleEndian
@@ -360,7 +360,7 @@ final class EmbeddingService {
     }
 
     /// Deserialize embedding from binary data
-    private func deserializeEmbedding(_ data: Data) -> [Float] {
+    nonisolated func deserializeEmbedding(_ data: Data) -> [Float] {
         var embedding: [Float] = []
         embedding.reserveCapacity(data.count / 4)
 

oAI/Services/GitSyncService.swift

@@ -45,7 +45,7 @@ class GitSyncService {
     func testConnection() async throws -> String {
         let url = try buildAuthenticatedURL()
         _ = try await runGit(["ls-remote", url])
-        return "Connected to \(extractProvider())"
+        return "Connected to \(Self.extractProvider(from: settings.syncRepoURL))"
     }
 
     /// Clone repository to local path
@@ -507,7 +507,7 @@ class GitSyncService {
         }
     }
 
-    private func detectSecretsInText(_ text: String) -> [String] {
+    func detectSecretsInText(_ text: String) -> [String] {
         let patterns: [(name: String, pattern: String)] = [
             ("OpenAI Key", "sk-[a-zA-Z0-9]{32,}"),
             ("Anthropic Key", "sk-ant-[a-zA-Z0-9_-]+"),
@@ -610,7 +610,7 @@ class GitSyncService {
         }
     }
 
-    private func convertToSSH(_ url: String) -> String {
+    func convertToSSH(_ url: String) -> String {
         // If already SSH format, return as-is
         if url.hasPrefix("git@") {
             return url
@@ -642,7 +642,7 @@ class GitSyncService {
         return url
     }
 
-    private func injectCredentials(_ url: String, username: String, password: String) -> String {
+    func injectCredentials(_ url: String, username: String, password: String) -> String {
         // Convert https://github.com/user/repo.git
         // To: https://username:password@github.com/user/repo.git
 
@@ -697,14 +697,13 @@ class GitSyncService {
         }
     }
 
-    private func sanitizeFilename(_ name: String) -> String {
+    func sanitizeFilename(_ name: String) -> String {
         // Remove invalid filename characters
         let invalid = CharacterSet(charactersIn: "/\\:*?\"<>|")
         return name.components(separatedBy: invalid).joined(separator: "-")
     }
 
-    private func extractProvider() -> String {
+    static func extractProvider(from url: String) -> String {
-        let url = settings.syncRepoURL
         if url.contains("github.com") {
             return "GitHub"
         } else if url.contains("gitlab.com") {

oAI/Services/MCPService.swift

@@ -23,6 +23,7 @@
 
 import Foundation
 import os
+import PDFKit
 
 @Observable
 class MCPService {
@@ -155,7 +156,7 @@ class MCPService {
         var tools: [Tool] = [
             makeTool(
                 name: "read_file",
-                description: "Read the contents of a file. Returns the text content of the file. Maximum file size is 10MB.",
+                description: "Read the contents of a file. Returns the text content of the file. PDFs are supported (text layer is extracted automatically) — scanned/image-only PDFs with no text layer will return an error. Maximum file size is 10MB.",
                 properties: [
                     "file_path": prop("string", "The absolute path to the file to read")
                 ],
@@ -172,7 +173,7 @@ class MCPService {
             ),
             makeTool(
                 name: "search_files",
-                description: "Search for files by name pattern or content. Use 'pattern' for filename glob matching (e.g. '*.swift'). Use 'content_search' for searching inside file contents.",
+                description: "Search for files by name pattern or content. Use 'pattern' for filename glob matching (e.g. '*.swift'). Use 'content_search' for searching inside file contents (PDF text layers are searched too).",
                 properties: [
                     "pattern": prop("string", "Glob pattern to match filenames (e.g. '*.py', 'README*')"),
                     "search_path": prop("string", "Directory to search in (defaults to first allowed folder)"),
@@ -536,8 +537,17 @@ class MCPService {
             return ["error": "File too large (\(sizeMB) MB, max 10 MB)"]
         }
 
-        guard let content = try? String(contentsOfFile: resolved, encoding: .utf8) else {
+        let content: String
-            return ["error": "Cannot read file as UTF-8 text: \(filePath)"]
+        if (resolved as NSString).pathExtension.lowercased() == "pdf" {
+            guard let extracted = extractPDFText(atPath: resolved) else {
+                return ["error": "Could not extract text from PDF (it may be scanned/image-only with no text layer, encrypted, or corrupted): \(filePath)"]
+            }
+            content = extracted
+        } else {
+            guard let text = try? String(contentsOfFile: resolved, encoding: .utf8) else {
+                return ["error": "Cannot read file as UTF-8 text: \(filePath)"]
+            }
+            content = text
         }
 
         var finalContent = content
@@ -554,6 +564,19 @@ class MCPService {
         return ["content": finalContent, "path": resolved, "size": fileSize]
     }
 
+    /// Extracts plain text from a PDF's text layer, page by page. Returns nil for
+    /// scanned/image-only PDFs (no text layer), encrypted, or otherwise unreadable files.
+    func extractPDFText(atPath path: String) -> String? {
+        guard let document = PDFDocument(url: URL(fileURLWithPath: path)) else { return nil }
+        var text = ""
+        for i in 0..<document.pageCount {
+            guard let page = document.page(at: i), let pageText = page.string else { continue }
+            text += pageText + "\n\n"
+        }
+        let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+        return trimmed.isEmpty ? nil : text
+    }
+
     private func listDirectory(dirPath: String, recursive: Bool) -> [String: Any] {
         let resolved = ((dirPath as NSString).expandingTildeInPath as NSString).standardizingPath
 
@@ -660,10 +683,13 @@ class MCPService {
 
             // Content search if requested
             if let searchText = contentSearch, !searchText.isEmpty {
-                guard let content = try? String(contentsOfFile: fullPath, encoding: .utf8) else {
+                let content: String?
-                    continue
+                if (fullPath as NSString).pathExtension.lowercased() == "pdf" {
+                    content = extractPDFText(atPath: fullPath)
+                } else {
+                    content = try? String(contentsOfFile: fullPath, encoding: .utf8)
                 }
-                if !content.localizedCaseInsensitiveContains(searchText) {
+                guard let content, content.localizedCaseInsensitiveContains(searchText) else {
                     continue
                 }
             }
@@ -944,7 +970,7 @@ class MCPService {
         let readOnlyTools: [Tool] = [
             makeTool(
                 name: "read_file",
-                description: "Read the contents of a file. Maximum file size is 10MB.",
+                description: "Read the contents of a file. PDFs are supported (text layer extracted automatically). Maximum file size is 10MB.",
                 properties: ["file_path": prop("string", "The absolute path to the file to read")],
                 required: ["file_path"]
             ),

oAI/Utilities/Extensions/Color+Extensions.swift

@@ -62,6 +62,7 @@ extension Color {
         case .anthropic: return Color(hex: "#d4895a")    // Orange
         case .openai: return Color(hex: "#10a37f")       // Green
         case .ollama: return Color(hex: "#ffffff")       // White
+        case .appleOnDevice: return Color(hex: "#636366")  // Apple grey
         }
     }
     

oAI/ViewModels/ChatViewModel.swift

@@ -151,8 +151,14 @@ Don't narrate future actions ("Let me...") - just use the tools.
 
     /// Builds the complete system prompt by combining default + conditional sections + custom
     private var effectiveSystemPrompt: String {
+        // Tool guidance, the user's custom prompt, and Agent Skills all generally assume tool
+        // access and can easily blow past small context windows (e.g. Apple's on-device 4K
+        // limit) — skip all three for tool-incapable models.
+        let modelSupportsTools = selectedModel?.capabilities.tools ?? true
+
         // Check if user wants to replace the default prompt entirely (BYOP mode)
-        if settings.customPromptMode == .replace,
+        if modelSupportsTools,
+           settings.customPromptMode == .replace,
            let customPrompt = settings.systemPrompt,
            !customPrompt.isEmpty {
             // BYOP: Use ONLY the custom prompt
@@ -170,29 +176,32 @@ Don't narrate future actions ("Let me...") - just use the tools.
         }
 
         // Add tool-specific guidelines if MCP is enabled (tools are available)
-        if mcpEnabled {
+        if mcpEnabled && modelSupportsTools {
             prompt += toolUsageGuidelines
         }
 
         // Append custom prompt if in append mode and custom prompt exists
-        if settings.customPromptMode == .append,
+        if modelSupportsTools,
+           settings.customPromptMode == .append,
            let customPrompt = settings.systemPrompt,
            !customPrompt.isEmpty {
             prompt += "\n\n---\n\nAdditional Instructions:\n" + customPrompt
         }
 
         // Append active agent skills (SKILL.md-style behavioral instructions)
-        let activeSkills = settings.agentSkills.filter { $0.isActive }
+        if modelSupportsTools {
-        if !activeSkills.isEmpty {
+            let activeSkills = settings.agentSkills.filter { $0.isActive }
-            prompt += "\n\n---\n\n## Installed Skills\n\nThe following skills are active. Apply them when relevant:\n\n"
+            if !activeSkills.isEmpty {
-            for skill in activeSkills {
+                prompt += "\n\n---\n\n## Installed Skills\n\nThe following skills are active. Apply them when relevant:\n\n"
-                prompt += "### \(skill.name)\n\n\(skill.content)\n\n"
+                for skill in activeSkills {
-                let files = AgentSkillFilesService.shared.readTextFiles(for: skill.id)
+                    prompt += "### \(skill.name)\n\n\(skill.content)\n\n"
-                if !files.isEmpty {
+                    let files = AgentSkillFilesService.shared.readTextFiles(for: skill.id)
-                    prompt += "**Skill Data Files:**\n\n"
+                    if !files.isEmpty {
-                    for (name, content) in files {
+                        prompt += "**Skill Data Files:**\n\n"
-                        let ext = URL(fileURLWithPath: name).pathExtension.lowercased()
+                        for (name, content) in files {
-                        prompt += "**\(name):**\n```\(ext)\n\(content)\n```\n\n"
+                            let ext = URL(fileURLWithPath: name).pathExtension.lowercased()
+                            prompt += "**\(name):**\n```\(ext)\n\(content)\n```\n\n"
+                        }
                     }
                 }
             }
@@ -413,15 +422,17 @@ Don't narrate future actions ("Let me...") - just use the tools.
     /// Update the selected model and keep currentProvider + settings in sync.
     /// Call this whenever the user picks a model in the model selector.
     func selectModel(_ model: ModelInfo) {
-        let newProvider = inferProvider(from: model.id) ?? currentProvider
+        let newProvider = Self.inferProvider(from: model.id) ?? currentProvider
         selectedModel = model
         currentProvider = newProvider
         MCPService.shared.resetBashSessionApproval()
     }
 
-    func inferProviderPublic(from modelId: String) -> Settings.Provider? { inferProvider(from: modelId) }
+    func inferProviderPublic(from modelId: String) -> Settings.Provider? { Self.inferProvider(from: modelId) }
 
-    private func inferProvider(from modelId: String) -> Settings.Provider? {
+    nonisolated static func inferProvider(from modelId: String) -> Settings.Provider? {
+        // Apple Foundation Models
+        if modelId.hasPrefix("apple-") { return .appleOnDevice }
         // OpenRouter models always contain a "/" (e.g. "anthropic/claude-3-5-sonnet")
         if modelId.contains("/") { return .openrouter }
         // Anthropic direct (e.g. "claude-sonnet-4-5-20250929")
@@ -437,7 +448,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
     /// Shows a system message only on failure or on a successful switch.
     @MainActor
     private func switchToConversationModel(_ modelId: String) async {
-        guard let targetProvider = inferProvider(from: modelId) else {
+        guard let targetProvider = Self.inferProvider(from: modelId) else {
             showSystemMessage("⚠️ Could not determine provider for model '\(modelId)' — keeping current model")
             return
         }
@@ -942,7 +953,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                             messages[index].tokens = usage.completionTokens
                             if let model = selectedModel {
                                 let hasPricing = model.pricing.prompt > 0 || model.pricing.completion > 0
-                                let cost: Double? = hasPricing ? calculateCost(usage: usage, pricing: model.pricing) : nil
+                                let cost: Double? = hasPricing ? Self.calculateCost(usage: usage, pricing: model.pricing) : nil
                                 messages[index].cost = cost
                                 sessionStats.addMessage(inputTokens: usage.promptTokens, outputTokens: usage.completionTokens, cost: cost)
                             }
@@ -1006,7 +1017,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                             messages[index].tokens = usage.completionTokens
                             if let model = selectedModel {
                                 let hasPricing = model.pricing.prompt > 0 || model.pricing.completion > 0
-                                let cost: Double? = hasPricing ? calculateCost(usage: usage, pricing: model.pricing) : nil
+                                let cost: Double? = hasPricing ? Self.calculateCost(usage: usage, pricing: model.pricing) : nil
                                 messages[index].cost = cost
                                 sessionStats.addMessage(inputTokens: usage.promptTokens, outputTokens: usage.completionTokens, cost: cost)
                             }
@@ -1306,7 +1317,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                         sessionStats.addMessage(inputTokens: usage.promptTokens, outputTokens: usage.completionTokens, cost: cost)
                     }
                 }
-                _ = detectGoodbyePhrase(in: "")
+                _ = Self.detectGoodbyePhrase(in: "")
             } catch {
                 if let index = messages.firstIndex(where: { $0.id == messageId }) {
                     messages[index].content = "❌ Image generation failed: \(error.localizedDescription)"
@@ -1582,7 +1593,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                     // Nothing worth showing yet — still record usage/cost for this turn.
                     if let usage = totalUsage, let model = selectedModel {
                         let hasPricing = model.pricing.prompt > 0 || model.pricing.completion > 0
-                        let cost: Double? = hasPricing ? calculateCost(usage: usage, pricing: model.pricing) : nil
+                        let cost: Double? = hasPricing ? Self.calculateCost(usage: usage, pricing: model.pricing) : nil
                         sessionStats.addMessage(
                             inputTokens: usage.promptTokens,
                             outputTokens: usage.completionTokens,
@@ -1607,7 +1618,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
                     // Calculate cost
                     if let usage = totalUsage, let model = selectedModel {
                         let hasPricing = model.pricing.prompt > 0 || model.pricing.completion > 0
-                        let cost: Double? = hasPricing ? calculateCost(usage: usage, pricing: model.pricing) : nil
+                        let cost: Double? = hasPricing ? Self.calculateCost(usage: usage, pricing: model.pricing) : nil
                         if let index = messages.lastIndex(where: { $0.id == assistantMessage.id }) {
                             messages[index].cost = cost
                         }
@@ -1888,40 +1899,43 @@ Don't narrate future actions ("Let me...") - just use the tools.
         }
     }
 
+    /// Pure auto-save eligibility check, pulled out of `shouldAutoSave()` so the criteria
+    /// (enabled, configured, cloned, min message count, not-already-saved) can be tested
+    /// without a live ChatViewModel/GitSyncService/SettingsService.
+    nonisolated static func shouldAutoSave(
+        syncEnabled: Bool,
+        syncAutoSave: Bool,
+        syncConfigured: Bool,
+        isCloned: Bool,
+        chatMessageCount: Int,
+        minMessages: Int,
+        lastSavedConversationId: String?,
+        currentConversationHash: String
+    ) -> Bool {
+        guard syncEnabled && syncAutoSave else { return false }
+        guard syncConfigured else { return false }
+        guard isCloned else { return false }
+        guard chatMessageCount >= minMessages else { return false }
+        if let lastSavedId = lastSavedConversationId, lastSavedId == currentConversationHash {
+            return false // Already saved this exact conversation
+        }
+        return true
+    }
+
     /// Check if conversation should be auto-saved based on criteria
     func shouldAutoSave() -> Bool {
-        // Check if auto-save is enabled
-        guard settings.syncEnabled && settings.syncAutoSave else {
-            return false
-        }
-
-        // Check if sync is configured
-        guard settings.syncConfigured else {
-            return false
-        }
-
-        // Check if repository is cloned
-        guard GitSyncService.shared.syncStatus.isCloned else {
-            return false
-        }
-
-        // Check minimum message count
         let chatMessages = messages.filter { $0.role == .user || $0.role == .assistant }
-        guard chatMessages.count >= settings.syncAutoSaveMinMessages else {
+        let currentHash = chatMessages.map { $0.content }.joined()
-            return false
+        return Self.shouldAutoSave(
-        }
+            syncEnabled: settings.syncEnabled,
-
+            syncAutoSave: settings.syncAutoSave,
-        // Check if already auto-saved this conversation
+            syncConfigured: settings.syncConfigured,
-        // (prevent duplicate saves)
+            isCloned: GitSyncService.shared.syncStatus.isCloned,
-        if let lastSavedId = settings.syncLastAutoSaveConversationId {
+            chatMessageCount: chatMessages.count,
-            // Create a hash of current conversation to detect if it's the same one
+            minMessages: settings.syncAutoSaveMinMessages,
-            let currentHash = chatMessages.map { $0.content }.joined()
+            lastSavedConversationId: settings.syncLastAutoSaveConversationId,
-            if lastSavedId == currentHash {
+            currentConversationHash: currentHash
-                return false // Already saved this exact conversation
+        )
-            }
-        }
-
-        return true
     }
 
     /// Auto-save the current conversation with background summarization
@@ -2038,7 +2052,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
     }
 
     /// Detect goodbye phrases in user message
-    func detectGoodbyePhrase(in text: String) -> Bool {
+    nonisolated static func detectGoodbyePhrase(in text: String) -> Bool {
         let lowercased = text.lowercased()
         let goodbyePhrases = [
             "bye", "goodbye", "bye bye", "good bye",
@@ -2078,7 +2092,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
         updateConversationTracking()
 
         // Check for goodbye phrase
-        if detectGoodbyePhrase(in: text) {
+        if Self.detectGoodbyePhrase(in: text) {
             Log.ui.info("Goodbye phrase detected - triggering auto-save")
             // Wait a bit to see if user continues
             try? await Task.sleep(for: .seconds(30))
@@ -2259,7 +2273,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
     /// pricing when present: cache writes cost 1.25x the base input rate, cache
     /// reads cost 0.1x. `usage.promptTokens` is already the uncached remainder —
     /// it does not need cache tokens subtracted from it.
-    private func calculateCost(usage: ChatResponse.Usage, pricing: ModelInfo.Pricing) -> Double {
+    nonisolated static func calculateCost(usage: ChatResponse.Usage, pricing: ModelInfo.Pricing) -> Double {
         let inputCost = Double(usage.promptTokens) * pricing.prompt / 1_000_000
         let cacheReadCost = Double(usage.cacheReadInputTokens ?? 0) * pricing.prompt * 0.1 / 1_000_000
         let cacheWriteCost = Double(usage.cacheCreationInputTokens ?? 0) * pricing.prompt * 1.25 / 1_000_000

oAI/Views/Screens/CreditsView.swift

@@ -78,6 +78,20 @@ struct CreditsView: View {
                             .font(.system(size: 40))
                             .foregroundColor(.green)
                             .padding(.top)
+
+                    case .appleOnDevice:
+                        Text("Apple Intelligence")
+                            .font(.headline)
+                        Text("On-device and free — no credits or API key needed.")
+                            .font(.body)
+                            .foregroundColor(.secondary)
+                        Text("⚠️ Beta — Apple's Foundation Models framework is still in active development.")
+                            .font(.caption)
+                            .foregroundColor(.secondary)
+                        Image(systemName: "apple.logo")
+                            .font(.system(size: 40))
+                            .foregroundColor(.secondary)
+                            .padding(.top)
                     }
                 }
 

oAI/Views/Screens/SettingsView.swift

@@ -23,6 +23,7 @@
 
 import SwiftUI
 import UniformTypeIdentifiers
+import FoundationModels
 
 struct SettingsView: View {
     @Environment(\.dismiss) var dismiss
@@ -319,6 +320,36 @@ It's better to admit "I need more information" or "I cannot do that" than to fak
             }
         }
 
+        // Apple Intelligence
+        VStack(alignment: .leading, spacing: 6) {
+            sectionHeader("Apple Intelligence")
+            formSection {
+                row("Status") {
+                    appleIntelligenceStatusBadge
+                }
+                rowDivider()
+                row("Model") {
+                    Text("On-Device (4K context)")
+                        .foregroundStyle(.secondary)
+                }
+                rowDivider()
+                row("") {
+                    Button("Open Apple Intelligence Settings") {
+                        if let url = URL(string: "x-apple.systempreferences:com.apple.preference.aisettings") {
+                            NSWorkspace.shared.open(url)
+                        }
+                    }
+                }
+                VStack(alignment: .leading, spacing: 2) {
+                    Text("⚠️ Beta — Apple's on-device model is still in active development (currently macOS 27 beta). Expect rough edges: a small 4K context window, occasional generation errors, and no tool support yet.")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                }
+                .padding(.horizontal, 12)
+                .padding(.bottom, 8)
+            }
+        }
+
         // Features
         VStack(alignment: .leading, spacing: 6) {
             sectionHeader("Features")
@@ -3089,6 +3120,28 @@ It's better to admit "I need more information" or "I cannot do that" than to fak
         formatter.unitsStyle = .full
         return formatter.localizedString(for: date, relativeTo: .now)
     }
+
+    @ViewBuilder
+    private var appleIntelligenceStatusBadge: some View {
+        let availability = SystemLanguageModel.default.availability
+        switch availability {
+        case .available:
+            Label("Available", systemImage: "checkmark.circle.fill")
+                .foregroundStyle(.green)
+        case .unavailable(.deviceNotEligible):
+            Label("Not supported on this Mac", systemImage: "xmark.circle.fill")
+                .foregroundStyle(.red)
+        case .unavailable(.appleIntelligenceNotEnabled):
+            Label("Not enabled — open Apple Intelligence Settings", systemImage: "exclamationmark.circle.fill")
+                .foregroundStyle(.orange)
+        case .unavailable(.modelNotReady):
+            Label("Model downloading…", systemImage: "arrow.down.circle.fill")
+                .foregroundStyle(.orange)
+        default:
+            Label("Unavailable", systemImage: "questionmark.circle.fill")
+                .foregroundStyle(.secondary)
+        }
+    }
 }
 
 #Preview {

oAITests/AIProviderTests.swift

@@ -0,0 +1,81 @@
+//
+//  AIProviderTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("ChatResponse / Usage decoding")
+struct AIProviderTests {
+
+    @Test("Usage decodes token counts and cache fields from snake_case keys")
+    func usageDecodesTokenCounts() throws {
+        let json = """
+        {
+            "prompt_tokens": 100,
+            "completion_tokens": 50,
+            "total_tokens": 150,
+            "cache_creation_input_tokens": 20,
+            "cache_read_input_tokens": 10
+        }
+        """.data(using: .utf8)!
+        let usage = try JSONDecoder().decode(ChatResponse.Usage.self, from: json)
+        #expect(usage.promptTokens == 100)
+        #expect(usage.completionTokens == 50)
+        #expect(usage.totalTokens == 150)
+        #expect(usage.cacheCreationInputTokens == 20)
+        #expect(usage.cacheReadInputTokens == 10)
+    }
+
+    @Test("Usage.rawCostUSD is always nil after decoding, even if a matching key were present")
+    func usageRawCostNeverDecoded() throws {
+        // rawCostUSD has no CodingKeys entry at all -- it's only ever set via the
+        // memberwise init, never from API JSON. Confirm decode always yields nil,
+        // which is exactly the "$0.0000 cost" regression this guards against.
+        let json = """
+        {
+            "prompt_tokens": 1,
+            "completion_tokens": 1,
+            "total_tokens": 2,
+            "raw_cost_u_s_d": 5.0
+        }
+        """.data(using: .utf8)!
+        let usage = try JSONDecoder().decode(ChatResponse.Usage.self, from: json)
+        #expect(usage.rawCostUSD == nil)
+    }
+
+    @Test("Usage cache fields are nil when absent from the response")
+    func usageMissingCacheFields() throws {
+        let json = #"{"prompt_tokens":1,"completion_tokens":1,"total_tokens":2}"#.data(using: .utf8)!
+        let usage = try JSONDecoder().decode(ChatResponse.Usage.self, from: json)
+        #expect(usage.cacheCreationInputTokens == nil)
+        #expect(usage.cacheReadInputTokens == nil)
+    }
+
+    @Test("ChatResponse decodes core fields and forces toolCalls/generatedImages to nil")
+    func chatResponseDecodesCoreFieldsOnly() throws {
+        let json = """
+        {
+            "id": "resp-1",
+            "model": "test-model",
+            "content": "hello there",
+            "role": "assistant",
+            "finishReason": "stop",
+            "created": 1700000000
+        }
+        """.data(using: .utf8)!
+        let response = try JSONDecoder().decode(ChatResponse.self, from: json)
+        #expect(response.id == "resp-1")
+        #expect(response.model == "test-model")
+        #expect(response.content == "hello there")
+        #expect(response.role == "assistant")
+        #expect(response.finishReason == "stop")
+        // Not part of CodingKeys -- always nil straight out of decode.
+        #expect(response.toolCalls == nil)
+        #expect(response.generatedImages == nil)
+    }
+}

oAITests/AnthropicProviderTests.swift

@@ -0,0 +1,207 @@
+//
+//  AnthropicProviderTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("AnthropicProvider request/response conversion")
+struct AnthropicProviderTests {
+
+    private var provider: AnthropicProvider { AnthropicProvider(apiKey: "test-key") }
+
+    private func decodeBody(_ urlRequest: URLRequest) throws -> [String: Any] {
+        try JSONSerialization.jsonObject(with: urlRequest.httpBody!) as! [String: Any]
+    }
+
+    // MARK: - buildURLRequest
+
+    @Test("System messages are pulled out of the message list into a top-level system field")
+    func systemMessageExtracted() throws {
+        let messages = [
+            Message(role: .system, content: "be concise"),
+            Message(role: .user, content: "hi")
+        ]
+        let request = ChatRequest(messages: messages, model: "claude-sonnet-4-5")
+        let (urlRequest, _) = try provider.buildURLRequest(from: request, stream: false)
+        let body = try decodeBody(urlRequest)
+
+        let apiMessages = body["messages"] as? [[String: Any]]
+        #expect(apiMessages?.count == 1) // system message removed from the array
+        #expect(apiMessages?.first?["role"] as? String == "user")
+
+        let system = body["system"] as? [[String: Any]]
+        #expect(system?.first?["text"] as? String == "be concise")
+        let cacheControl = system?.first?["cache_control"] as? [String: String]
+        #expect(cacheControl?["type"] == "ephemeral")
+    }
+
+    @Test("The last message gets a cache_control breakpoint on its content block")
+    func lastMessageGetsCacheBreakpoint() throws {
+        let messages = [
+            Message(role: .user, content: "first"),
+            Message(role: .assistant, content: "second"),
+            Message(role: .user, content: "third")
+        ]
+        let request = ChatRequest(messages: messages, model: "claude-sonnet-4-5")
+        let (urlRequest, _) = try provider.buildURLRequest(from: request, stream: false)
+        let body = try decodeBody(urlRequest)
+        let apiMessages = body["messages"] as? [[String: Any]]
+
+        // Earlier messages keep plain string content (no cache breakpoint).
+        #expect(apiMessages?[0]["content"] as? String == "first")
+        #expect(apiMessages?[1]["content"] as? String == "second")
+
+        // The last message's content becomes an array with a cache_control block.
+        let lastContent = apiMessages?[2]["content"] as? [[String: Any]]
+        #expect(lastContent?.first?["text"] as? String == "third")
+        let cacheControl = lastContent?.first?["cache_control"] as? [String: String]
+        #expect(cacheControl?["type"] == "ephemeral")
+    }
+
+    @Test("max_tokens defaults to 16000 when not specified on the request")
+    func defaultMaxTokens() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "claude-sonnet-4-5")
+        let (urlRequest, _) = try provider.buildURLRequest(from: request, stream: false)
+        let body = try decodeBody(urlRequest)
+        #expect(body["max_tokens"] as? Int == 16000)
+    }
+
+    @Test("Online mode adds a web_search tool even with no explicit tools requested")
+    func onlineModeAddsWebSearchTool() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "claude-sonnet-4-5", onlineMode: true)
+        let (urlRequest, _) = try provider.buildURLRequest(from: request, stream: false)
+        let body = try decodeBody(urlRequest)
+        let tools = body["tools"] as? [[String: Any]]
+        #expect(tools?.first?["name"] as? String == "web_search")
+        // tool_choice is only added when the caller supplied explicit tools.
+        #expect(body["tool_choice"] == nil)
+    }
+
+    @Test("Empty message content is replaced with a placeholder rather than sent blank")
+    func emptyContentGetsPlaceholder() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "   ")], model: "claude-sonnet-4-5")
+        let (urlRequest, _) = try provider.buildURLRequest(from: request, stream: false)
+        let body = try decodeBody(urlRequest)
+        let apiMessages = body["messages"] as? [[String: Any]]
+        // This is also the last message, so it gets wrapped in a cache-control array.
+        let content = apiMessages?.first?["content"] as? [[String: Any]]
+        #expect(content?.first?["text"] as? String == "[Image]")
+    }
+
+    // MARK: - parseResponse
+
+    @Test("Parses text content, usage, and stop_reason from a well-formed response")
+    func parsesWellFormedResponse() throws {
+        let json: [String: Any] = [
+            "id": "msg_123",
+            "model": "claude-sonnet-4-5",
+            "content": [["type": "text", "text": "hello there"]],
+            "stop_reason": "end_turn",
+            "usage": ["input_tokens": 10, "output_tokens": 5]
+        ]
+        let data = try JSONSerialization.data(withJSONObject: json)
+        let response = try provider.parseResponse(data: data)
+        #expect(response.id == "msg_123")
+        #expect(response.content == "hello there")
+        #expect(response.finishReason == "end_turn")
+        #expect(response.usage?.promptTokens == 10)
+        #expect(response.usage?.completionTokens == 5)
+        #expect(response.toolCalls == nil)
+    }
+
+    @Test("Parses a tool_use block into a ToolCallInfo with JSON-encoded arguments")
+    func parsesToolUseBlock() throws {
+        let json: [String: Any] = [
+            "id": "msg_1",
+            "model": "claude-sonnet-4-5",
+            "content": [
+                ["type": "tool_use", "id": "tool_1", "name": "get_weather", "input": ["city": "Oslo"]]
+            ],
+            "usage": ["input_tokens": 1, "output_tokens": 1]
+        ]
+        let data = try JSONSerialization.data(withJSONObject: json)
+        let response = try provider.parseResponse(data: data)
+        #expect(response.toolCalls?.count == 1)
+        #expect(response.toolCalls?.first?.functionName == "get_weather")
+        #expect(response.toolCalls?.first?.arguments.contains("Oslo") == true)
+    }
+
+    @Test("Throws invalidResponse for non-JSON data")
+    func throwsOnInvalidJSON() {
+        let data = "not json".data(using: .utf8)!
+        #expect(throws: (any Error).self) {
+            try provider.parseResponse(data: data)
+        }
+    }
+
+    // MARK: - convertParametersToDict
+
+    @Test("Converts tool parameters to Anthropic's input_schema dict shape")
+    func convertsParametersToInputSchema() {
+        let params = Tool.Function.Parameters(
+            type: "object",
+            properties: [
+                "city": Tool.Function.Parameters.Property(type: "string", description: "City name"),
+                "unit": Tool.Function.Parameters.Property(type: "string", description: "Unit", enum: ["celsius", "fahrenheit"])
+            ],
+            required: ["city"]
+        )
+        let dict = provider.convertParametersToDict(params)
+        #expect(dict["type"] as? String == "object")
+        #expect(dict["required"] as? [String] == ["city"])
+        let properties = dict["properties"] as? [String: Any]
+        let cityProp = properties?["city"] as? [String: Any]
+        #expect(cityProp?["type"] as? String == "string")
+        let unitProp = properties?["unit"] as? [String: Any]
+        #expect(unitProp?["enum"] as? [String] == ["celsius", "fahrenheit"])
+    }
+
+    @Test("Array-typed properties include a nested items schema")
+    func convertsArrayItemsSchema() {
+        let params = Tool.Function.Parameters(
+            type: "object",
+            properties: [
+                "tags": Tool.Function.Parameters.Property(type: "array", description: "Tags", items: .init(type: "string"))
+            ],
+            required: nil
+        )
+        let dict = provider.convertParametersToDict(params)
+        let properties = dict["properties"] as? [String: Any]
+        let tagsProp = properties?["tags"] as? [String: Any]
+        let items = tagsProp?["items"] as? [String: Any]
+        #expect(items?["type"] as? String == "string")
+        #expect(dict["required"] == nil)
+    }
+
+    // MARK: - resolveFallbackPricing
+
+    @Test("Exact-length single prefix match returns that tier's pricing")
+    func fallbackPricingSingleMatch() {
+        let pricing = AnthropicProvider.resolveFallbackPricing(for: "claude-haiku-4-5-20251001")
+        #expect(pricing.prompt == 0.80)
+        #expect(pricing.completion == 4.0)
+    }
+
+    @Test("Longest matching prefix wins when multiple prefixes could match")
+    func fallbackPricingLongestPrefixWins() {
+        let fallback: [(prefix: String, prompt: Double, completion: Double)] = [
+            ("claude", 1.0, 2.0),
+            ("claude-sonnet", 3.0, 15.0),
+        ]
+        let pricing = AnthropicProvider.resolveFallbackPricing(for: "claude-sonnet-5", fallback: fallback)
+        #expect(pricing.prompt == 3.0)
+        #expect(pricing.completion == 15.0)
+    }
+
+    @Test("An unmatched model ID prices at zero rather than guessing")
+    func fallbackPricingNoMatch() {
+        let pricing = AnthropicProvider.resolveFallbackPricing(for: "some-future-unknown-model")
+        #expect(pricing.prompt == 0)
+        #expect(pricing.completion == 0)
+    }
+}

oAITests/BackupServiceTests.swift

@@ -0,0 +1,105 @@
+//
+//  BackupServiceTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("BackupService.decideFavoritesSync")
+struct BackupServiceFavoritesSyncTests {
+
+    private let now = Date(timeIntervalSince1970: 1_700_000_000)
+
+    @Test("No remote copy yet -- push local state")
+    func noRemoteCopy() {
+        let decision = BackupService.decideFavoritesSync(localIds: ["a", "b"], localUpdatedAt: "", remote: nil, now: now)
+        #expect(decision == .pushLocal)
+    }
+
+    @Test("Remote is newer -- apply it locally")
+    func remoteNewer() {
+        let remote = FavoritesPayload(updatedAt: "2026-02-01T00:00:00Z", ids: ["x", "y"])
+        let decision = BackupService.decideFavoritesSync(
+            localIds: ["a"],
+            localUpdatedAt: "2026-01-01T00:00:00Z",
+            remote: remote,
+            now: now
+        )
+        #expect(decision == .applyRemote(ids: ["x", "y"], updatedAt: "2026-02-01T00:00:00Z"))
+    }
+
+    @Test("Local is newer -- push local state, don't touch remote")
+    func localNewer() {
+        let remote = FavoritesPayload(updatedAt: "2026-01-01T00:00:00Z", ids: ["x"])
+        let decision = BackupService.decideFavoritesSync(
+            localIds: ["a"],
+            localUpdatedAt: "2026-02-01T00:00:00Z",
+            remote: remote,
+            now: now
+        )
+        #expect(decision == .pushLocal)
+    }
+
+    @Test("Tied timestamps with different sets -- merge via union and push")
+    func tiedTimestampsDifferentSets() {
+        let remote = FavoritesPayload(updatedAt: "", ids: ["b", "c"])
+        let decision = BackupService.decideFavoritesSync(localIds: ["a", "b"], localUpdatedAt: "", remote: remote, now: now)
+        guard case .mergeAndPush(let ids, let updatedAt) = decision else {
+            Issue.record("Expected .mergeAndPush")
+            return
+        }
+        #expect(ids == ["a", "b", "c"])
+        #expect(!updatedAt.isEmpty) // stamped with `now`, not left blank
+    }
+
+    @Test("Tied timestamps with identical sets -- no-op, already in sync")
+    func tiedTimestampsIdenticalSets() {
+        let remote = FavoritesPayload(updatedAt: "2026-01-01T00:00:00Z", ids: ["a", "b"])
+        let decision = BackupService.decideFavoritesSync(
+            localIds: ["a", "b"],
+            localUpdatedAt: "2026-01-01T00:00:00Z",
+            remote: remote,
+            now: now
+        )
+        #expect(decision == .noop)
+    }
+}
+
+@Suite("BackupService.isBackupDue")
+struct BackupServiceAutoBackupTests {
+
+    private let now = Date(timeIntervalSince1970: 1_700_000_000)
+    private let oneHour: TimeInterval = 3600
+
+    @Test("Manual frequency is never due")
+    func manualNeverDue() {
+        #expect(!BackupService.isBackupDue(frequency: "manual", lastBackupDate: nil, now: now))
+        #expect(!BackupService.isBackupDue(frequency: "manual", lastBackupDate: now.addingTimeInterval(-1_000_000), now: now))
+    }
+
+    @Test("No prior backup at all is always due, regardless of frequency")
+    func noPriorBackupIsAlwaysDue() {
+        #expect(BackupService.isBackupDue(frequency: "daily", lastBackupDate: nil, now: now))
+        #expect(BackupService.isBackupDue(frequency: "weekly", lastBackupDate: nil, now: now))
+    }
+
+    @Test("Daily: not due before 24 hours have passed, due at or after")
+    func dailyThreshold() {
+        let justUnder = now.addingTimeInterval(-(24 * oneHour - 1))
+        let exactly = now.addingTimeInterval(-(24 * oneHour))
+        #expect(!BackupService.isBackupDue(frequency: "daily", lastBackupDate: justUnder, now: now))
+        #expect(BackupService.isBackupDue(frequency: "daily", lastBackupDate: exactly, now: now))
+    }
+
+    @Test("Weekly: not due before 7 days have passed, due at or after")
+    func weeklyThreshold() {
+        let justUnder = now.addingTimeInterval(-(7 * 24 * oneHour - 1))
+        let exactly = now.addingTimeInterval(-(7 * 24 * oneHour))
+        #expect(!BackupService.isBackupDue(frequency: "weekly", lastBackupDate: justUnder, now: now))
+        #expect(BackupService.isBackupDue(frequency: "weekly", lastBackupDate: exactly, now: now))
+    }
+}

oAITests/ChatViewModelPureLogicTests.swift

@@ -0,0 +1,167 @@
+//
+//  ChatViewModelPureLogicTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+@testable import oAI
+
+@Suite("ChatViewModel pure static helpers")
+struct ChatViewModelPureLogicTests {
+
+    // MARK: - detectGoodbyePhrase
+
+    @Test("Recognizes a clear farewell phrase")
+    func detectsGoodbye() {
+        #expect(ChatViewModel.detectGoodbyePhrase(in: "OK, bye!"))
+        #expect(ChatViewModel.detectGoodbyePhrase(in: "That's all, thanks."))
+        #expect(ChatViewModel.detectGoodbyePhrase(in: "Have a good day"))
+    }
+
+    @Test("Does not false-positive on a word that merely contains a phrase as a substring")
+    func doesNotMatchSubstring() {
+        // "bye" is a whole-word match target -- "goodbyeee" should not match "bye"
+        // as a substring because of the \b word-boundary regex.
+        #expect(!ChatViewModel.detectGoodbyePhrase(in: "goodbyeee is not a real word"))
+    }
+
+    @Test("Does not match ordinary polite phrases that aren't farewells")
+    func doesNotMatchPoliteRequests() {
+        #expect(!ChatViewModel.detectGoodbyePhrase(in: "Thanks, that's helpful!"))
+        #expect(!ChatViewModel.detectGoodbyePhrase(in: "Done with step one, what's next?"))
+    }
+
+    @Test("Matching is case-insensitive")
+    func matchIsCaseInsensitive() {
+        #expect(ChatViewModel.detectGoodbyePhrase(in: "BYE BYE"))
+    }
+
+    // MARK: - inferProvider
+
+    @Test("Model ID with a slash is inferred as OpenRouter")
+    func infersOpenRouter() {
+        #expect(ChatViewModel.inferProvider(from: "anthropic/claude-3-5-sonnet") == .openrouter)
+    }
+
+    @Test("claude- prefixed model is inferred as direct Anthropic")
+    func infersAnthropic() {
+        #expect(ChatViewModel.inferProvider(from: "claude-sonnet-4-5-20250929") == .anthropic)
+    }
+
+    @Test("gpt-/o1/o3/dall-e/chatgpt prefixed models are inferred as OpenAI")
+    func infersOpenAI() {
+        #expect(ChatViewModel.inferProvider(from: "gpt-4o") == .openai)
+        #expect(ChatViewModel.inferProvider(from: "o1-preview") == .openai)
+        #expect(ChatViewModel.inferProvider(from: "o3-mini") == .openai)
+        #expect(ChatViewModel.inferProvider(from: "dall-e-3") == .openai)
+        #expect(ChatViewModel.inferProvider(from: "chatgpt-4o-latest") == .openai)
+    }
+
+    @Test("A bare local model name with no recognized prefix falls back to Ollama")
+    func fallsBackToOllama() {
+        #expect(ChatViewModel.inferProvider(from: "llama3.2") == .ollama)
+    }
+
+    @Test("apple- prefixed model is inferred as Apple on-device")
+    func infersAppleOnDevice() {
+        #expect(ChatViewModel.inferProvider(from: "apple-on-device") == .appleOnDevice)
+    }
+
+    // MARK: - calculateCost
+
+    @Test("Base prompt and completion cost with no cache usage")
+    func calculatesBaseCost() {
+        let usage = ChatResponse.Usage(promptTokens: 1_000_000, completionTokens: 1_000_000, totalTokens: 2_000_000)
+        let pricing = ModelInfo.Pricing(prompt: 3.0, completion: 15.0)
+        #expect(ChatViewModel.calculateCost(usage: usage, pricing: pricing) == 18.0)
+    }
+
+    @Test("Cache read tokens are charged at 0.1x the prompt rate")
+    func calculatesCacheReadCost() {
+        let usage = ChatResponse.Usage(
+            promptTokens: 0,
+            completionTokens: 0,
+            totalTokens: 1_000_000,
+            cacheReadInputTokens: 1_000_000
+        )
+        let pricing = ModelInfo.Pricing(prompt: 3.0, completion: 15.0)
+        #expect(ChatViewModel.calculateCost(usage: usage, pricing: pricing) == 0.3)
+    }
+
+    @Test("Cache write tokens are charged at 1.25x the prompt rate")
+    func calculatesCacheWriteCost() {
+        let usage = ChatResponse.Usage(
+            promptTokens: 0,
+            completionTokens: 0,
+            totalTokens: 1_000_000,
+            cacheCreationInputTokens: 1_000_000
+        )
+        let pricing = ModelInfo.Pricing(prompt: 3.0, completion: 15.0)
+        #expect(ChatViewModel.calculateCost(usage: usage, pricing: pricing) == 3.75)
+    }
+
+    @Test("Zero usage produces zero cost")
+    func zeroUsageIsZeroCost() {
+        let usage = ChatResponse.Usage(promptTokens: 0, completionTokens: 0, totalTokens: 0)
+        let pricing = ModelInfo.Pricing(prompt: 3.0, completion: 15.0)
+        #expect(ChatViewModel.calculateCost(usage: usage, pricing: pricing) == 0.0)
+    }
+
+    // MARK: - shouldAutoSave
+
+    private func autoSaveEligible(
+        syncEnabled: Bool = true,
+        syncAutoSave: Bool = true,
+        syncConfigured: Bool = true,
+        isCloned: Bool = true,
+        chatMessageCount: Int = 10,
+        minMessages: Int = 4,
+        lastSavedConversationId: String? = nil,
+        currentConversationHash: String = "hash-a"
+    ) -> Bool {
+        ChatViewModel.shouldAutoSave(
+            syncEnabled: syncEnabled,
+            syncAutoSave: syncAutoSave,
+            syncConfigured: syncConfigured,
+            isCloned: isCloned,
+            chatMessageCount: chatMessageCount,
+            minMessages: minMessages,
+            lastSavedConversationId: lastSavedConversationId,
+            currentConversationHash: currentConversationHash
+        )
+    }
+
+    @Test("Eligible when every criterion is satisfied")
+    func autoSaveEligibleWhenAllCriteriaMet() {
+        #expect(autoSaveEligible())
+    }
+
+    @Test("Not eligible when sync or auto-save is disabled")
+    func autoSaveIneligibleWhenDisabled() {
+        #expect(!autoSaveEligible(syncEnabled: false))
+        #expect(!autoSaveEligible(syncAutoSave: false))
+    }
+
+    @Test("Not eligible when sync isn't configured or the repo isn't cloned")
+    func autoSaveIneligibleWhenNotConfiguredOrCloned() {
+        #expect(!autoSaveEligible(syncConfigured: false))
+        #expect(!autoSaveEligible(isCloned: false))
+    }
+
+    @Test("Not eligible below the minimum message count")
+    func autoSaveIneligibleBelowMinimumMessages() {
+        #expect(!autoSaveEligible(chatMessageCount: 2, minMessages: 4))
+    }
+
+    @Test("Not eligible if this exact conversation was already auto-saved")
+    func autoSaveIneligibleWhenAlreadySaved() {
+        #expect(!autoSaveEligible(lastSavedConversationId: "hash-a", currentConversationHash: "hash-a"))
+    }
+
+    @Test("Eligible when the last saved hash differs from the current conversation")
+    func autoSaveEligibleWhenConversationChanged() {
+        #expect(autoSaveEligible(lastSavedConversationId: "hash-a", currentConversationHash: "hash-b"))
+    }
+}

oAITests/ContextSelectionServiceDBTests.swift

@@ -0,0 +1,120 @@
+//
+//  ContextSelectionServiceDBTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("ContextSelectionService DB-coupled paths, against a throwaway in-memory queue")
+struct ContextSelectionServiceDBTests {
+
+    /// Persists messages, then loads them back so their `id`s match the DB rows
+    /// (saveConversation assigns fresh row ids internally, distinct from the ids
+    /// on the Message values passed in).
+    private func persistedMessages(_ db: DatabaseService, _ messages: [Message]) throws -> (conversationId: UUID, messages: [Message]) {
+        let saved = try db.saveConversation(name: "Test", messages: messages)
+        let loaded = try db.loadConversation(id: saved.id)
+        return (saved.id, loaded?.1 ?? [])
+    }
+
+    // MARK: - isMessageStarred
+
+    @Test("A message with no metadata row is not starred")
+    func unstarredByDefault() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (_, messages) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        #expect(service.isMessageStarred(messages[0]) == false)
+    }
+
+    @Test("A message starred via setMessageStarred reports starred")
+    func starredAfterSetting() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (_, messages) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        try db.setMessageStarred(messageId: messages[0].id, starred: true)
+        #expect(service.isMessageStarred(messages[0]) == true)
+    }
+
+    // MARK: - getSummariesForExcludedRange
+
+    @Test("No summaries recorded returns an empty array")
+    func noSummariesReturnsEmpty() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (conversationId, _) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        let summaries = service.getSummariesForExcludedRange(conversationId: conversationId, totalMessages: 30, selectedCount: 10)
+        #expect(summaries.isEmpty)
+    }
+
+    @Test("A summary covering only excluded messages is included")
+    func summaryForExcludedRangeIncluded() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (conversationId, _) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        // 30 total, 10 selected -> messages 0..<20 are excluded
+        try db.saveConversationSummary(conversationId: conversationId, startIndex: 0, endIndex: 15, summary: "early stuff", model: nil, tokenCount: nil)
+
+        let summaries = service.getSummariesForExcludedRange(conversationId: conversationId, totalMessages: 30, selectedCount: 10)
+        #expect(summaries == ["early stuff"])
+    }
+
+    @Test("A summary covering messages that were kept is excluded")
+    func summaryForKeptRangeExcluded() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (conversationId, _) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        // 30 total, 10 selected -> messages 0..<20 are excluded; this summary ends at 25, inside the kept range
+        try db.saveConversationSummary(conversationId: conversationId, startIndex: 15, endIndex: 25, summary: "later stuff", model: nil, tokenCount: nil)
+
+        let summaries = service.getSummariesForExcludedRange(conversationId: conversationId, totalMessages: 30, selectedCount: 10)
+        #expect(summaries.isEmpty)
+    }
+
+    // MARK: - smartSelection (end to end through the DB seam)
+
+    @Test("A starred older message is pulled in alongside the recent window")
+    func starredMessagePulledIntoSelection() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+
+        var all: [Message] = []
+        let base = Date()
+        for i in 0..<15 {
+            all.append(Message(role: i % 2 == 0 ? .user : .assistant, content: "msg \(i)", timestamp: base.addingTimeInterval(Double(i))))
+        }
+        let (_, persisted) = try persistedMessages(db, all)
+
+        // Star an old message that's outside the last-10 window (index 2)
+        try db.setMessageStarred(messageId: persisted[2].id, starred: true)
+
+        let window = service.smartSelection(allMessages: persisted, maxTokens: 100_000, conversationId: nil)
+        #expect(window.messages.contains { $0.id == persisted[2].id })
+    }
+
+    @Test("An unstarred, unimportant old message outside the recent window is excluded")
+    func unstarredOldMessageExcluded() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+
+        var all: [Message] = []
+        let base = Date()
+        for i in 0..<15 {
+            all.append(Message(role: i % 2 == 0 ? .user : .assistant, content: "msg \(i)", timestamp: base.addingTimeInterval(Double(i))))
+        }
+        let (_, persisted) = try persistedMessages(db, all)
+
+        let window = service.smartSelection(allMessages: persisted, maxTokens: 100_000, conversationId: nil)
+        #expect(window.messages.contains { $0.id == persisted[0].id } == false)
+        #expect(window.excludedCount == 5)
+    }
+}

oAITests/ContextSelectionServiceTests.swift

@@ -0,0 +1,67 @@
+//
+//  ContextSelectionServiceTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+@testable import oAI
+
+@Suite("ContextSelectionService pure scoring helpers")
+struct ContextSelectionServiceTests {
+
+    private var service: ContextSelectionService { ContextSelectionService.shared }
+
+    // MARK: - getImportanceScore
+
+    @Test("A short message with no cost or token data scores from length alone")
+    func lowScoreForPlainShortMessage() {
+        let message = Message(role: .user, content: "hi")
+        #expect(service.getImportanceScore(message) < 0.01)
+    }
+
+    @Test("Cost, length, and token factors combine to the exact weighted sum")
+    func combinesWeightedFactors() {
+        // cost 0.005 / 0.01 = 0.5 -> * 0.5 weight = 0.25
+        // 1000 chars / 2000 = 0.5 -> * 0.3 weight = 0.15
+        // 500 tokens / 1000 = 0.5 -> * 0.2 weight = 0.1
+        // total = 0.5
+        let message = Message(role: .assistant, content: String(repeating: "a", count: 1000), tokens: 500, cost: 0.005)
+        #expect(abs(service.getImportanceScore(message) - 0.5) < 0.0001)
+    }
+
+    @Test("Score is capped at 1.0 even when every factor maxes out and would otherwise overflow it")
+    func scoreIsCappedAtOne() {
+        let message = Message(
+            role: .assistant,
+            content: String(repeating: "a", count: 5000), // well past the 2000-char max
+            tokens: 5000, // well past the 1000-token max
+            cost: 1.0 // well past the $0.01 max
+        )
+        #expect(service.getImportanceScore(message) == 1.0)
+    }
+
+    // MARK: - estimateTokens
+
+    @Test("Uses the message's actual token count when present")
+    func usesActualTokenCountWhenAvailable() {
+        let messages = [Message(role: .user, content: "irrelevant for this test", tokens: 42)]
+        #expect(service.estimateTokens(messages) == 42)
+    }
+
+    @Test("Falls back to content.count / 4 when tokens is nil")
+    func fallsBackToCharacterEstimate() {
+        let messages = [Message(role: .user, content: String(repeating: "x", count: 40))]
+        #expect(service.estimateTokens(messages) == 10)
+    }
+
+    @Test("Sums estimates across a mix of messages with and without token counts")
+    func sumsAcrossMixedMessages() {
+        let messages = [
+            Message(role: .user, content: "ignored", tokens: 100),
+            Message(role: .assistant, content: String(repeating: "y", count: 20)), // 20/4 = 5
+        ]
+        #expect(service.estimateTokens(messages) == 105)
+    }
+}

oAITests/DatabaseServiceTests.swift

@@ -0,0 +1,123 @@
+//
+//  DatabaseServiceTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("DatabaseService migrations, against a throwaway in-memory queue")
+struct DatabaseServiceMigrationTests {
+
+    @Test("All v1-v8 tables exist after migration")
+    func allTablesExist() {
+        let db = DatabaseService.makeInMemory()
+        let expectedTables = [
+            "conversations", "messages", "settings", "command_history",
+            "email_logs", "message_metadata", "message_embeddings",
+            "conversation_embeddings", "conversation_summaries",
+        ]
+        for table in expectedTables {
+            #expect(db.tableExists(table), "expected table \(table) to exist")
+        }
+    }
+
+    @Test("v4 adds modelId to messages and primaryModel to conversations")
+    func v4AddsModelColumns() {
+        let db = DatabaseService.makeInMemory()
+        #expect(db.columnNames(in: "messages").contains("modelId"))
+        #expect(db.columnNames(in: "conversations").contains("primaryModel"))
+    }
+
+    @Test("messages table has the expected v1 columns")
+    func messagesTableColumns() {
+        let db = DatabaseService.makeInMemory()
+        let columns = Set(db.columnNames(in: "messages"))
+        let expected: Set<String> = ["id", "conversationId", "role", "content", "tokens", "cost", "timestamp", "sortOrder"]
+        #expect(expected.isSubset(of: columns))
+    }
+
+    @Test("message_metadata table has the expected v6 columns")
+    func messageMetadataColumns() {
+        let db = DatabaseService.makeInMemory()
+        let columns = Set(db.columnNames(in: "message_metadata"))
+        #expect(columns == ["message_id", "importance_score", "user_starred", "summary", "chunk_index"])
+    }
+
+    @Test("conversation_summaries table has the expected v8 columns")
+    func conversationSummariesColumns() {
+        let db = DatabaseService.makeInMemory()
+        let columns = Set(db.columnNames(in: "conversation_summaries"))
+        #expect(columns == ["id", "conversation_id", "start_message_index", "end_message_index", "summary", "token_count", "created_at", "summary_model"])
+    }
+
+    @Test("A nonexistent table reports as absent, not a crash")
+    func nonexistentTableReportsAbsent() {
+        let db = DatabaseService.makeInMemory()
+        #expect(db.tableExists("not_a_real_table") == false)
+    }
+
+    @Test("Two in-memory instances are isolated from each other")
+    func instancesAreIsolated() throws {
+        let dbA = DatabaseService.makeInMemory()
+        let dbB = DatabaseService.makeInMemory()
+
+        _ = try dbA.saveConversation(name: "only in A", messages: [Message(role: .user, content: "hi")])
+
+        #expect(try dbA.listConversations().count == 1)
+        #expect(try dbB.listConversations().count == 0)
+    }
+}
+
+@Suite("DatabaseService settings CRUD, against a throwaway in-memory queue")
+struct DatabaseServiceSettingsTests {
+
+    @Test("Round-trips a plain setting")
+    func roundTripsSetting() {
+        let db = DatabaseService.makeInMemory()
+        db.setSetting(key: "theme", value: "dark")
+        #expect((try? db.loadAllSettings()["theme"]) == "dark")
+    }
+
+    @Test("Deletes a setting")
+    func deletesSetting() {
+        let db = DatabaseService.makeInMemory()
+        db.setSetting(key: "temp", value: "1")
+        db.deleteSetting(key: "temp")
+        #expect((try? db.loadAllSettings()["temp"]) == nil)
+    }
+}
+
+@Suite("DatabaseService conversation + message persistence, against a throwaway in-memory queue")
+struct DatabaseServiceConversationTests {
+
+    @Test("Saving a conversation round-trips its messages via loadConversation")
+    func savesAndLoadsConversation() throws {
+        let db = DatabaseService.makeInMemory()
+        let messages = [
+            Message(role: .user, content: "hello"),
+            Message(role: .assistant, content: "hi there"),
+        ]
+        let saved = try db.saveConversation(name: "Test Chat", messages: messages)
+
+        let loaded = try db.loadConversation(id: saved.id)
+        #expect(loaded?.0.name == "Test Chat")
+        #expect(loaded?.1.map(\.content) == ["hello", "hi there"])
+    }
+
+    @Test("System messages are excluded from persistence")
+    func systemMessagesExcluded() throws {
+        let db = DatabaseService.makeInMemory()
+        let messages = [
+            Message(role: .system, content: "tool call"),
+            Message(role: .user, content: "hello"),
+        ]
+        let saved = try db.saveConversation(name: "Test", messages: messages)
+        let loaded = try db.loadConversation(id: saved.id)
+        #expect(loaded?.1.count == 1)
+        #expect(loaded?.1.first?.content == "hello")
+    }
+}

oAITests/EmbeddingServiceTests.swift

@@ -0,0 +1,35 @@
+//
+//  EmbeddingServiceTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+@testable import oAI
+
+@Suite("EmbeddingService serialization")
+struct EmbeddingServiceTests {
+
+    @Test("Serialize then deserialize round-trips an embedding exactly")
+    func roundTrip() {
+        let original: [Float] = [0.0, 1.0, -1.0, 3.14159, -0.0001, 1_000_000.5]
+        let data = EmbeddingService.shared.serializeEmbedding(original)
+        let restored = EmbeddingService.shared.deserializeEmbedding(data)
+        #expect(restored == original)
+    }
+
+    @Test("Serialized data is exactly 4 bytes per float")
+    func serializedSizeIsFourBytesPerFloat() {
+        let embedding: [Float] = Array(repeating: 0.5, count: 10)
+        let data = EmbeddingService.shared.serializeEmbedding(embedding)
+        #expect(data.count == 40)
+    }
+
+    @Test("Empty embedding serializes to empty data and back")
+    func emptyEmbedding() {
+        let data = EmbeddingService.shared.serializeEmbedding([])
+        #expect(data.isEmpty)
+        #expect(EmbeddingService.shared.deserializeEmbedding(data).isEmpty)
+    }
+}

oAITests/GitSyncServiceTests.swift

@@ -0,0 +1,108 @@
+//
+//  GitSyncServiceTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+@testable import oAI
+
+@Suite("GitSyncService pure helpers")
+struct GitSyncServiceTests {
+
+    private var service: GitSyncService { GitSyncService.shared }
+
+    // MARK: - convertToSSH
+
+    @Test("Already-SSH URLs pass through unchanged")
+    func convertToSSHAlreadySSH() {
+        #expect(service.convertToSSH("git@github.com:user/repo.git") == "git@github.com:user/repo.git")
+    }
+
+    @Test("HTTPS URL converts to SSH form")
+    func convertToSSHFromHTTPS() {
+        #expect(service.convertToSSH("https://gitlab.pm/rune/oAI-Sync.git") == "git@gitlab.pm:rune/oAI-Sync.git")
+    }
+
+    @Test("HTTP URL converts to SSH form")
+    func convertToSSHFromHTTP() {
+        #expect(service.convertToSSH("http://example.com/user/repo.git") == "git@example.com:user/repo.git")
+    }
+
+    @Test("Malformed URL with no path segment is returned unchanged")
+    func convertToSSHMalformedNoSlash() {
+        #expect(service.convertToSSH("https://onlyhost") == "https://onlyhost")
+    }
+
+    @Test("Unknown scheme is returned unchanged")
+    func convertToSSHUnknownScheme() {
+        #expect(service.convertToSSH("ftp://example.com/repo") == "ftp://example.com/repo")
+    }
+
+    // MARK: - injectCredentials
+
+    @Test("Injects username and password into an HTTPS URL")
+    func injectCredentialsHTTPS() {
+        let result = service.injectCredentials("https://gitlab.pm/rune/repo.git", username: "rune", password: "secret")
+        #expect(result == "https://rune:secret@gitlab.pm/rune/repo.git")
+    }
+
+    @Test("Non-HTTPS URLs are returned unchanged (credentials not injected)")
+    func injectCredentialsNonHTTPS() {
+        let result = service.injectCredentials("git@gitlab.pm:rune/repo.git", username: "rune", password: "secret")
+        #expect(result == "git@gitlab.pm:rune/repo.git")
+    }
+
+    // MARK: - sanitizeFilename
+
+    @Test("Strips filesystem-invalid characters, replacing each with a dash")
+    func sanitizeFilenameStripsInvalidChars() {
+        #expect(service.sanitizeFilename("a/b\\c:d*e?f\"g<h>i|j") == "a-b-c-d-e-f-g-h-i-j")
+    }
+
+    @Test("Leaves an already-valid filename untouched")
+    func sanitizeFilenameValidInput() {
+        #expect(service.sanitizeFilename("My Chat 2026-01-15") == "My Chat 2026-01-15")
+    }
+
+    // MARK: - detectSecretsInText
+
+    @Test("Detects an OpenAI-style API key")
+    func detectSecretsOpenAIKey() {
+        let text = "here's my key: sk-abcdefghijklmnopqrstuvwxyz123456"
+        #expect(service.detectSecretsInText(text).contains("OpenAI Key"))
+    }
+
+    @Test("Detects a GitHub personal access token")
+    func detectSecretsGitHubToken() {
+        let text = "token=ghp_abcdefghijklmnopqrstuvwxyz1234567890"
+        #expect(service.detectSecretsInText(text).contains("Access Token"))
+    }
+
+    @Test("Plain conversational text has no detected secrets")
+    func detectSecretsCleanText() {
+        #expect(service.detectSecretsInText("Just a normal conversation about the weather.").isEmpty)
+    }
+
+    @Test("Does not flag an OpenAI-shaped string one character short of the length threshold")
+    func detectSecretsJustBelowThreshold() {
+        // "sk-" + 31 chars = 34 total, but the pattern requires 32+ chars after "sk-"
+        let shortKey = "sk-" + String(repeating: "a", count: 31)
+        #expect(!service.detectSecretsInText(shortKey).contains("OpenAI Key"))
+    }
+
+    // MARK: - extractProvider
+
+    @Test("Recognizes github.com, gitlab.com, and gitea URLs by name")
+    func extractProviderRecognizesKnownHosts() {
+        #expect(GitSyncService.extractProvider(from: "https://github.com/user/repo.git") == "GitHub")
+        #expect(GitSyncService.extractProvider(from: "https://gitlab.com/user/repo.git") == "GitLab")
+        #expect(GitSyncService.extractProvider(from: "https://my-gitea-instance.example.com/user/repo.git") == "Gitea")
+    }
+
+    @Test("Falls back to a generic label for an unrecognized host")
+    func extractProviderFallsBackForUnknownHost() {
+        #expect(GitSyncService.extractProvider(from: "https://gitlab.pm/rune/oai-swift.git") == "Git repository")
+    }
+}

oAITests/GitignoreParserTests.swift

@@ -0,0 +1,83 @@
+//
+//  GitignoreParserTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+@testable import oAI
+
+@Suite("GitignoreParser")
+struct GitignoreParserTests {
+
+    private func parser(for content: String) -> GitignoreParser {
+        var parser = GitignoreParser(rootPath: "/tmp/fake-root")
+        parser.parseContent(content)
+        return parser
+    }
+
+    @Test("Simple extension wildcard matches at any depth")
+    func extensionWildcard() {
+        let p = parser(for: "*.log")
+        #expect(p.isIgnored("debug.log"))
+        #expect(p.isIgnored("nested/debug.log"))
+        #expect(!p.isIgnored("debug.txt"))
+    }
+
+    @Test("Directory pattern matches the directory and everything under it")
+    func directoryPattern() {
+        let p = parser(for: "build/")
+        #expect(p.isIgnored("build"))
+        #expect(p.isIgnored("build/output.txt"))
+        #expect(p.isIgnored("foo/build/output.txt"))
+        #expect(!p.isIgnored("rebuild"))
+    }
+
+    @Test("Path-anchored pattern only matches that exact relative path, not nested occurrences")
+    func pathAnchoredWildcard() {
+        let p = parser(for: "src/*.tmp")
+        #expect(p.isIgnored("src/foo.tmp"))
+        #expect(!p.isIgnored("other/src/foo.tmp"))
+        #expect(!p.isIgnored("src/sub/foo.tmp"))
+    }
+
+    @Test("Double-star matches across any number of intermediate directories")
+    func doubleStarPattern() {
+        let p = parser(for: "**/logs")
+        #expect(p.isIgnored("logs"))
+        #expect(p.isIgnored("a/logs"))
+        #expect(p.isIgnored("a/b/logs"))
+        #expect(p.isIgnored("a/logs/file.txt"))
+        #expect(!p.isIgnored("logsfile"))
+    }
+
+    @Test("Negation un-ignores a path matched by an earlier rule")
+    func negation() {
+        let p = parser(for: "*.log\n!important.log")
+        #expect(p.isIgnored("debug.log"))
+        #expect(!p.isIgnored("important.log"))
+    }
+
+    @Test("Comments and blank lines are skipped, not treated as patterns")
+    func commentsAndBlankLines() {
+        let p = parser(for: "# a comment\n\n*.log\n   \n")
+        #expect(p.isIgnored("x.log"))
+        #expect(!p.isIgnored("# a comment"))
+    }
+
+    @Test("Leading slash still matches (root-anchoring is not enforced by this implementation)")
+    func leadingSlashPattern() {
+        // Documents actual current behavior: the leading "/" is stripped without
+        // truly restricting the match to the root level, unlike real git.
+        let p = parser(for: "/dist")
+        #expect(p.isIgnored("dist"))
+        #expect(p.isIgnored("dist/file.txt"))
+    }
+
+    @Test("No rules means nothing is ignored")
+    func noRules() {
+        let p = parser(for: "")
+        #expect(!p.isIgnored("anything.txt"))
+    }
+}

oAITests/MCPServicePDFTests.swift

@@ -0,0 +1,68 @@
+//
+//  MCPServicePDFTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+import CoreGraphics
+import AppKit
+@testable import oAI
+
+@Suite("MCPService PDF text extraction")
+struct MCPServicePDFTests {
+
+    /// Builds a real, well-formed single-page PDF (via CoreGraphics) containing the given text,
+    /// writes it to a temp file, and returns the path. Using CoreGraphics rather than hand-rolled
+    /// PDF bytes avoids flakiness from malformed xref tables etc.
+    private func makeTestPDF(text: String) throws -> String {
+        let path = FileManager.default.temporaryDirectory
+            .appendingPathComponent(UUID().uuidString)
+            .appendingPathExtension("pdf")
+
+        let pdfData = NSMutableData()
+        let consumer = CGDataConsumer(data: pdfData as CFMutableData)!
+        var mediaBox = CGRect(x: 0, y: 0, width: 200, height: 200)
+        let context = CGContext(consumer: consumer, mediaBox: &mediaBox, nil)!
+
+        context.beginPDFPage(nil)
+        let attributedString = NSAttributedString(string: text, attributes: [.font: NSFont.systemFont(ofSize: 24)])
+        let line = CTLineCreateWithAttributedString(attributedString)
+        context.textPosition = CGPoint(x: 10, y: 100)
+        CTLineDraw(line, context)
+        context.endPDFPage()
+        context.closePDF()
+
+        try (pdfData as Data).write(to: path)
+        return path.path
+    }
+
+    @Test("Extracts text from a real PDF's text layer")
+    func extractsTextFromRealPDF() throws {
+        let path = try makeTestPDF(text: "Hello World")
+        defer { try? FileManager.default.removeItem(atPath: path) }
+
+        let extracted = MCPService.shared.extractPDFText(atPath: path)
+        #expect(extracted?.contains("Hello World") == true)
+    }
+
+    @Test("Returns nil for a nonexistent path")
+    func returnsNilForMissingFile() {
+        let extracted = MCPService.shared.extractPDFText(atPath: "/tmp/definitely-does-not-exist-\(UUID().uuidString).pdf")
+        #expect(extracted == nil)
+    }
+
+    @Test("Returns nil for a file that isn't a valid PDF")
+    func returnsNilForGarbageBytes() throws {
+        let path = FileManager.default.temporaryDirectory
+            .appendingPathComponent(UUID().uuidString)
+            .appendingPathExtension("pdf")
+        try Data("not a real pdf".utf8).write(to: path)
+        defer { try? FileManager.default.removeItem(at: path) }
+
+        let extracted = MCPService.shared.extractPDFText(atPath: path.path)
+        #expect(extracted == nil)
+    }
+}

oAITests/MessageCodableTests.swift

@@ -0,0 +1,93 @@
+//
+//  MessageCodableTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("Message Codable + Equatable")
+struct MessageCodableTests {
+
+    @Test("Transient fields don't survive an encode/decode round-trip")
+    func transientFieldsDoNotPersist() throws {
+        var message = Message(role: .assistant, content: "hi", isStreaming: true, generatedImages: [Data([0x01])])
+        message.isStarred = true
+        message.toolCalls = [ToolCallDetail(name: "test_tool", input: "{}", result: nil)]
+        message.thinkingContent = "reasoning..."
+
+        let data = try JSONEncoder().encode(message)
+        let decoded = try JSONDecoder().decode(Message.self, from: data)
+
+        #expect(decoded.content == "hi")
+        #expect(decoded.isStreaming == false)
+        #expect(decoded.isStarred == false)
+        #expect(decoded.generatedImages == nil)
+        #expect(decoded.toolCalls == nil)
+        #expect(decoded.thinkingContent == nil)
+    }
+
+    @Test("Persisted fields survive an encode/decode round-trip")
+    func persistedFieldsSurvive() throws {
+        let message = Message(
+            role: .user,
+            content: "what's the weather",
+            tokens: 42,
+            cost: 0.0012,
+            responseTime: 1.5,
+            wasInterrupted: true,
+            modelId: "claude-sonnet-5"
+        )
+        let data = try JSONEncoder().encode(message)
+        let decoded = try JSONDecoder().decode(Message.self, from: data)
+
+        #expect(decoded.id == message.id)
+        #expect(decoded.role == message.role)
+        #expect(decoded.content == message.content)
+        #expect(decoded.tokens == message.tokens)
+        #expect(decoded.cost == message.cost)
+        #expect(decoded.responseTime == message.responseTime)
+        #expect(decoded.wasInterrupted == message.wasInterrupted)
+        #expect(decoded.modelId == message.modelId)
+    }
+
+    @Test("Custom == ignores role, timestamp, attachments, and modelId")
+    func equalityIgnoresSomeFields() {
+        let base = Message(id: UUID(), role: .user, content: "same", timestamp: Date())
+        let differentRoleAndModel = Message(
+            id: base.id,
+            role: .assistant,
+            content: "same",
+            timestamp: Date(timeIntervalSince1970: 0),
+            modelId: "some-other-model"
+        )
+        // Documents actual current behavior: these fields are intentionally
+        // excluded from Message's custom == -- surprising if you don't know it.
+        #expect(base == differentRoleAndModel)
+    }
+
+    @Test("Custom == does distinguish on content")
+    func equalityDistinguishesContent() {
+        let a = Message(id: UUID(), role: .user, content: "one")
+        let b = Message(id: a.id, role: .user, content: "two")
+        #expect(a != b)
+    }
+
+    @Test("FileAttachment.typeFromExtension recognizes common types")
+    func attachmentTypeFromExtension() {
+        #expect(FileAttachment.typeFromExtension("photo.PNG") == .image)
+        #expect(FileAttachment.typeFromExtension("photo.jpg") == .image)
+        #expect(FileAttachment.typeFromExtension("doc.pdf") == .pdf)
+        #expect(FileAttachment.typeFromExtension("notes.md") == .text)
+        #expect(FileAttachment.typeFromExtension("noextension") == .text)
+    }
+
+    @Test("FileAttachment.mimeType matches the detected extension")
+    func attachmentMimeType() {
+        let attachment = FileAttachment(path: "image.webp", type: .image, data: nil)
+        #expect(attachment.mimeType == "image/webp")
+    }
+}

oAITests/OllamaProviderTests.swift

@@ -0,0 +1,79 @@
+//
+//  OllamaProviderTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("OllamaProvider request/response conversion")
+struct OllamaProviderTests {
+
+    private var provider: OllamaProvider { OllamaProvider() }
+
+    // MARK: - buildRequestBody
+
+    @Test("Builds a basic request body with model, messages, and stream flag")
+    func basicRequestBody() {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "llama3.2")
+        let body = provider.buildRequestBody(from: request, stream: true)
+        #expect(body["model"] as? String == "llama3.2")
+        #expect(body["stream"] as? Bool == true)
+        let messages = body["messages"] as? [[String: Any]]
+        #expect(messages?.count == 1)
+        #expect(messages?.first?["role"] as? String == "user")
+        #expect(messages?.first?["content"] as? String == "hi")
+    }
+
+    @Test("System prompt is prepended as its own system-role message")
+    func systemPromptPrepended() {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "llama3.2", systemPrompt: "be concise")
+        let body = provider.buildRequestBody(from: request, stream: false)
+        let messages = body["messages"] as? [[String: Any]]
+        #expect(messages?.count == 2)
+        #expect(messages?.first?["role"] as? String == "system")
+        #expect(messages?.first?["content"] as? String == "be concise")
+    }
+
+    @Test("maxTokens and temperature are nested under options only when present")
+    func optionsOnlyWhenPresent() {
+        let withOptions = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "llama3.2", maxTokens: 500, temperature: 0.7)
+        let bodyWithOptions = provider.buildRequestBody(from: withOptions, stream: false)
+        let options = bodyWithOptions["options"] as? [String: Any]
+        #expect(options?["num_predict"] as? Int == 500)
+        #expect(options?["temperature"] as? Double == 0.7)
+
+        let withoutOptions = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "llama3.2")
+        let bodyWithoutOptions = provider.buildRequestBody(from: withoutOptions, stream: false)
+        #expect(bodyWithoutOptions["options"] == nil)
+    }
+
+    // MARK: - parseOllamaResponse
+
+    @Test("Parses content and token counts from a well-formed response")
+    func parsesWellFormedResponse() {
+        let json: [String: Any] = [
+            "message": ["content": "the answer"],
+            "prompt_eval_count": 10,
+            "eval_count": 20
+        ]
+        let response = provider.parseOllamaResponse(json, model: "llama3.2")
+        #expect(response.content == "the answer")
+        #expect(response.role == "assistant")
+        #expect(response.finishReason == "stop")
+        #expect(response.usage?.promptTokens == 10)
+        #expect(response.usage?.completionTokens == 20)
+        #expect(response.usage?.totalTokens == 30)
+    }
+
+    @Test("Missing fields default to empty content and zero token counts")
+    func missingFieldsDefaultGracefully() {
+        let response = provider.parseOllamaResponse([:], model: "llama3.2")
+        #expect(response.content == "")
+        #expect(response.usage?.promptTokens == 0)
+        #expect(response.usage?.completionTokens == 0)
+    }
+}

oAITests/OpenAIProviderTests.swift

@@ -0,0 +1,89 @@
+//
+//  OpenAIProviderTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("OpenAIProvider request/response conversion")
+struct OpenAIProviderTests {
+
+    private var provider: OpenAIProvider { OpenAIProvider(apiKey: "test-key") }
+
+    // MARK: - buildURLRequest
+
+    @Test("Sets the Authorization header and JSON content type")
+    func setsAuthAndContentTypeHeaders() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "gpt-4o")
+        let urlRequest = try provider.buildURLRequest(from: request, stream: false)
+        #expect(urlRequest.value(forHTTPHeaderField: "Authorization") == "Bearer test-key")
+        #expect(urlRequest.value(forHTTPHeaderField: "Content-Type") == "application/json")
+        #expect(urlRequest.value(forHTTPHeaderField: "Accept") == nil)
+    }
+
+    @Test("Streaming requests add an SSE Accept header and stream_options")
+    func streamingAddsAcceptHeaderAndUsageOption() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "gpt-4o")
+        let urlRequest = try provider.buildURLRequest(from: request, stream: true)
+        #expect(urlRequest.value(forHTTPHeaderField: "Accept") == "text/event-stream")
+
+        let body = try JSONSerialization.jsonObject(with: urlRequest.httpBody!) as! [String: Any]
+        let streamOptions = body["stream_options"] as? [String: Any]
+        #expect(streamOptions?["include_usage"] as? Bool == true)
+    }
+
+    @Test("o1/o3 reasoning models omit temperature even when one is requested")
+    func reasoningModelsOmitTemperature() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "o1-preview", temperature: 0.7)
+        let urlRequest = try provider.buildURLRequest(from: request, stream: false)
+        let body = try JSONSerialization.jsonObject(with: urlRequest.httpBody!) as! [String: Any]
+        #expect(body["temperature"] == nil)
+    }
+
+    @Test("Non-reasoning models include the requested temperature")
+    func nonReasoningModelsIncludeTemperature() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "gpt-4o", temperature: 0.7)
+        let urlRequest = try provider.buildURLRequest(from: request, stream: false)
+        let body = try JSONSerialization.jsonObject(with: urlRequest.httpBody!) as! [String: Any]
+        #expect(body["temperature"] as? Double == 0.7)
+    }
+
+    @Test("A message with an image attachment produces multi-part vision-format content")
+    func imageAttachmentProducesMultipartContent() throws {
+        let attachment = FileAttachment(path: "photo.png", type: .image, data: Data([0x01]))
+        let message = Message(role: .user, content: "look at this", attachments: [attachment])
+        let request = ChatRequest(messages: [message], model: "gpt-4o")
+        let urlRequest = try provider.buildURLRequest(from: request, stream: false)
+        let body = try JSONSerialization.jsonObject(with: urlRequest.httpBody!) as! [String: Any]
+        let messages = body["messages"] as? [[String: Any]]
+        let content = messages?.first?["content"] as? [[String: Any]]
+        #expect(content?.count == 2)
+        #expect(content?.first?["type"] as? String == "text")
+        #expect(content?.last?["type"] as? String == "image_url")
+    }
+
+    // MARK: - convertToChatResponse
+
+    @Test("Returns an empty-content response when there are no choices, rather than throwing")
+    func convertToChatResponseEmptyChoicesFallback() {
+        let apiResponse = OpenRouterChatResponse(id: "x", model: "m", choices: [], usage: nil, created: 0)
+        let response = provider.convertToChatResponse(apiResponse)
+        #expect(response.content == "")
+        #expect(response.role == "assistant")
+    }
+
+    // MARK: - fallbackModels
+
+    @Test("Fallback models are non-empty, all support tools, and are sorted by name")
+    func fallbackModelsAreWellFormed() {
+        let models = provider.fallbackModels()
+        #expect(!models.isEmpty)
+        #expect(models.allSatisfy { $0.capabilities.tools == true })
+        #expect(models.allSatisfy { $0.capabilities.online == false })
+        #expect(models.map(\.name) == models.map(\.name).sorted())
+    }
+}

oAITests/OpenRouterModelsTests.swift

@@ -0,0 +1,132 @@
+//
+//  OpenRouterModelsTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("OpenRouterModels decoding")
+struct OpenRouterModelsTests {
+
+    // MARK: - Request-side: APIMessage.MessageContent (string-or-array union)
+
+    @Test("Request message content decodes a plain string")
+    func requestContentPlainString() throws {
+        let json = #"{"role":"user","content":"hello"}"#.data(using: .utf8)!
+        let message = try JSONDecoder().decode(OpenRouterChatRequest.APIMessage.self, from: json)
+        guard case .string(let text) = message.content else {
+            Issue.record("Expected .string case")
+            return
+        }
+        #expect(text == "hello")
+    }
+
+    @Test("Request message content decodes an array of content items")
+    func requestContentArray() throws {
+        let json = #"{"role":"user","content":[{"type":"text","text":"hi"}]}"#.data(using: .utf8)!
+        let message = try JSONDecoder().decode(OpenRouterChatRequest.APIMessage.self, from: json)
+        guard case .array(let items) = message.content else {
+            Issue.record("Expected .array case")
+            return
+        }
+        #expect(items.count == 1)
+    }
+
+    // MARK: - Request-side: ContentItem (text / image union, with string fallback)
+
+    @Test("ContentItem decodes a text block")
+    func contentItemText() throws {
+        let json = #"{"type":"text","text":"hi there"}"#.data(using: .utf8)!
+        let item = try JSONDecoder().decode(OpenRouterChatRequest.APIMessage.ContentItem.self, from: json)
+        guard case .text(let text) = item else {
+            Issue.record("Expected .text case")
+            return
+        }
+        #expect(text == "hi there")
+    }
+
+    @Test("ContentItem decodes an image_url block")
+    func contentItemImage() throws {
+        let json = #"{"type":"image_url","image_url":{"url":"https://example.com/x.png"}}"#.data(using: .utf8)!
+        let item = try JSONDecoder().decode(OpenRouterChatRequest.APIMessage.ContentItem.self, from: json)
+        guard case .image(let image) = item else {
+            Issue.record("Expected .image case")
+            return
+        }
+        #expect(image.imageUrl.url == "https://example.com/x.png")
+    }
+
+    @Test("ContentItem falls back to .text for a bare string")
+    func contentItemBareStringFallback() throws {
+        let json = #""just text""#.data(using: .utf8)!
+        let item = try JSONDecoder().decode(OpenRouterChatRequest.APIMessage.ContentItem.self, from: json)
+        guard case .text(let text) = item else {
+            Issue.record("Expected .text fallback case")
+            return
+        }
+        #expect(text == "just text")
+    }
+
+    // MARK: - Response-side: Choice.MessageContent (plain string vs content-block array)
+
+    @Test("Response message content decodes a plain string with no image blocks")
+    func responseContentPlainString() throws {
+        let json = #"{"role":"assistant","content":"the answer"}"#.data(using: .utf8)!
+        let content = try JSONDecoder().decode(OpenRouterChatResponse.Choice.MessageContent.self, from: json)
+        #expect(content.content == "the answer")
+        #expect(content.contentBlockImages.isEmpty)
+    }
+
+    @Test("Response message content extracts text and images from a content-block array")
+    func responseContentBlockArrayWithImage() throws {
+        let json = """
+        {
+            "role": "assistant",
+            "content": [
+                {"type": "text", "text": "here you go"},
+                {"type": "image_url", "image_url": {"url": "https://example.com/out.png"}}
+            ]
+        }
+        """.data(using: .utf8)!
+        let content = try JSONDecoder().decode(OpenRouterChatResponse.Choice.MessageContent.self, from: json)
+        #expect(content.content == "here you go")
+        #expect(content.contentBlockImages.count == 1)
+        #expect(content.contentBlockImages.first?.imageUrl.url == "https://example.com/out.png")
+    }
+
+    @Test("Response message content with no content field at all decodes to nil content, no images")
+    func responseContentMissing() throws {
+        let json = #"{"role":"assistant"}"#.data(using: .utf8)!
+        let content = try JSONDecoder().decode(OpenRouterChatResponse.Choice.MessageContent.self, from: json)
+        #expect(content.content == nil)
+        #expect(content.contentBlockImages.isEmpty)
+    }
+
+    // MARK: - Streaming: StreamChoice.Delta (same string-or-block-array shape, streamed)
+
+    @Test("Stream delta decodes a plain string content chunk")
+    func streamDeltaPlainString() throws {
+        let json = #"{"role":"assistant","content":"partial"}"#.data(using: .utf8)!
+        let delta = try JSONDecoder().decode(OpenRouterStreamChunk.StreamChoice.Delta.self, from: json)
+        #expect(delta.content == "partial")
+        #expect(delta.contentBlockImages.isEmpty)
+    }
+
+    @Test("Stream delta extracts images from a content-block array")
+    func streamDeltaContentBlockArrayWithImage() throws {
+        let json = """
+        {
+            "content": [
+                {"type": "image_url", "image_url": {"url": "https://example.com/stream.png"}}
+            ]
+        }
+        """.data(using: .utf8)!
+        let delta = try JSONDecoder().decode(OpenRouterStreamChunk.StreamChoice.Delta.self, from: json)
+        #expect(delta.contentBlockImages.count == 1)
+        #expect(delta.contentBlockImages.first?.imageUrl.url == "https://example.com/stream.png")
+    }
+}

oAITests/OpenRouterProviderTests.swift

@@ -0,0 +1,103 @@
+//
+//  OpenRouterProviderTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("OpenRouterProvider request/response conversion")
+struct OpenRouterProviderTests {
+
+    private var provider: OpenRouterProvider { OpenRouterProvider(apiKey: "test-key") }
+
+    // MARK: - buildAPIRequest
+
+    @Test("Plain text message with no attachments uses simple string content")
+    func buildRequestPlainText() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hello")], model: "openai/gpt-4o")
+        let apiRequest = try provider.buildAPIRequest(from: request)
+        guard case .string(let text) = apiRequest.messages.first?.content else {
+            Issue.record("Expected .string content for a message with no attachments")
+            return
+        }
+        #expect(text == "hello")
+    }
+
+    @Test("Message with an image attachment uses array content with a base64 data URL")
+    func buildRequestWithImageAttachment() throws {
+        let attachment = FileAttachment(path: "photo.png", type: .image, data: Data([0x01, 0x02]))
+        let message = Message(role: .user, content: "check this out", attachments: [attachment])
+        let request = ChatRequest(messages: [message], model: "openai/gpt-4o")
+        let apiRequest = try provider.buildAPIRequest(from: request)
+        guard case .array(let items) = apiRequest.messages.first?.content else {
+            Issue.record("Expected .array content for a message with attachments")
+            return
+        }
+        #expect(items.count == 2) // text + image
+    }
+
+    @Test("Online mode appends :online suffix, but not for image generation requests")
+    func onlineModeSuffix() throws {
+        let base = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "openai/gpt-4o", onlineMode: true)
+        let request = try provider.buildAPIRequest(from: base)
+        #expect(request.model == "openai/gpt-4o:online")
+
+        let imageGenRequest = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "openai/gpt-4o", onlineMode: true, imageGeneration: true)
+        let noSuffix = try provider.buildAPIRequest(from: imageGenRequest)
+        #expect(noSuffix.model == "openai/gpt-4o")
+    }
+
+    @Test("Online mode does not double-append :online if the model already has it")
+    func onlineModeNoDoubleSuffix() throws {
+        let request = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "openai/gpt-4o:online", onlineMode: true)
+        let apiRequest = try provider.buildAPIRequest(from: request)
+        #expect(apiRequest.model == "openai/gpt-4o:online")
+    }
+
+    @Test("Anthropic models get an explicit cache_control opt-in; others don't")
+    func cacheControlOnlyForAnthropic() throws {
+        let anthropicRequest = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "anthropic/claude-sonnet-4-5")
+        let anthropicAPI = try provider.buildAPIRequest(from: anthropicRequest)
+        #expect(anthropicAPI.cacheControl?.type == "ephemeral")
+
+        let openAIRequest = ChatRequest(messages: [Message(role: .user, content: "hi")], model: "openai/gpt-4o")
+        let openAIAPI = try provider.buildAPIRequest(from: openAIRequest)
+        #expect(openAIAPI.cacheControl == nil)
+    }
+
+    // MARK: - convertToChatResponse
+
+    @Test("Throws invalidResponse when there are no choices")
+    func convertToChatResponseThrowsOnEmptyChoices() {
+        let apiResponse = OpenRouterChatResponse(id: "x", model: "m", choices: [], usage: nil, created: 0)
+        #expect(throws: (any Error).self) {
+            try provider.convertToChatResponse(apiResponse)
+        }
+    }
+
+    // MARK: - decodeImageOutputs
+
+    @Test("Decodes a base64 data URL into raw Data")
+    func decodeImageOutputsValidDataURL() {
+        let payload = Data([0xDE, 0xAD, 0xBE, 0xEF])
+        let dataURL = "data:image/png;base64,\(payload.base64EncodedString())"
+        let output = OpenRouterChatResponse.ImageOutput(imageUrl: .init(url: dataURL))
+        let decoded = provider.decodeImageOutputs([output])
+        #expect(decoded?.first == payload)
+    }
+
+    @Test("Returns nil for an empty outputs array")
+    func decodeImageOutputsEmpty() {
+        #expect(provider.decodeImageOutputs([]) == nil)
+    }
+
+    @Test("Skips a malformed URL with no comma separator")
+    func decodeImageOutputsMalformedURL() {
+        let output = OpenRouterChatResponse.ImageOutput(imageUrl: .init(url: "not-a-data-url"))
+        #expect(provider.decodeImageOutputs([output]) == nil)
+    }
+}

oAITests/SettingsProviderTests.swift

@@ -0,0 +1,31 @@
+//
+//  SettingsProviderTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+@testable import oAI
+
+@Suite("Settings.Provider display metadata")
+struct SettingsProviderTests {
+
+    @Test("Apple on-device gets a dedicated display name, not a raw-value capitalization")
+    func appleOnDeviceDisplayName() {
+        #expect(Settings.Provider.appleOnDevice.displayName == "Apple Intelligence")
+    }
+
+    @Test("Apple on-device uses the Apple logo icon")
+    func appleOnDeviceIconName() {
+        #expect(Settings.Provider.appleOnDevice.iconName == "apple.logo")
+    }
+
+    @Test("Other providers still fall back to a capitalized raw value")
+    func otherProvidersUseCapitalizedRawValue() {
+        #expect(Settings.Provider.openrouter.displayName == "Openrouter")
+        #expect(Settings.Provider.anthropic.displayName == "Anthropic")
+        #expect(Settings.Provider.openai.displayName == "Openai")
+        #expect(Settings.Provider.ollama.displayName == "Ollama")
+    }
+}