style: format chat-latest support

CHANGELOG.md

@@ -5,6 +5,7 @@ All notable changes to the Tachikoma project will be documented in this file.
 ## [Unreleased]
 
 ### Added
+- Added first-class OpenAI `chat-latest` support with parsing aliases, Responses API routing, model capabilities, and usage estimates.
 - Added first-class MiniMax support with the `MiniMax-M2.7` catalog models, `MINIMAX_API_KEY` / `MINIMAX_BASE_URL` configuration, bearer-token Anthropic-compatible transport, model parsing shortcuts, usage estimates, and provider tests.
 - Added explicit LM Studio model shortcuts such as `lmstudio` and `lmstudio/openai/gpt-oss-120b` so local provider selections no longer fall through to Ollama custom IDs.
 
@@ -13,6 +14,7 @@ All notable changes to the Tachikoma project will be documented in this file.
 - Removed stale direct model support for retired or non-canonical IDs including GPT-5.1/5.2/pseudo-thinking models, deprecated Claude Sonnet/Opus 4 snapshots, Grok 2/3/4-fast rows, old Groq Llama/Mixtral/Gemma aliases, stale Mistral aliases, and invalid LM Studio `current`.
 
 ### Fixed
+- SwiftPM consumers now resolve Commander from the package URL instead of accidentally inheriting a sibling local checkout.
 - Ollama model parsing now preserves explicit custom vision model IDs such as `qwen2.5vl:3b` instead of falling back to `llama3.3` (#16).
 - Auth resolution now snapshots environment-ignore state consistently, preventing parallel tests and concurrent callers from falling back to stored OpenRouter credentials when an environment override is present.
 - SwiftPM consumers can now resolve Commander remotely instead of requiring a local `../Commander` checkout. Thanks @malpern.

Package.resolved

@@ -1,6 +1,15 @@
 {
-  "originHash" : "12a454cd38a6ae2519d652cc0872f7f18feb64690ce83d1507bae6db71c1841c",
+  "originHash" : "46472c9ff88e15d0aa5ee2b3eeaee7e4b8f12474173a0367b7922efa6c48a62b",
   "pins" : [
+    {
+      "identity" : "commander",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/steipete/Commander",
+      "state" : {
+        "revision" : "ae2ce746b386ff94b26648cfe5625cfa8d02639b",
+        "version" : "0.2.2"
+      }
+    },
     {
       "identity" : "eventsource",
       "kind" : "remoteSourceControl",

Package.swift

@@ -1,17 +1,9 @@
 // swift-tools-version: 6.2
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
-import Foundation
 import PackageDescription
 
-let packageDirectory = URL(fileURLWithPath: #filePath).deletingLastPathComponent()
-let localCommanderPath = packageDirectory
-    .deletingLastPathComponent()
-    .appendingPathComponent("Commander")
-    .appendingPathComponent("Package.swift")
-let commanderDependency: Package.Dependency = FileManager.default.fileExists(atPath: localCommanderPath.path)
-    ? .package(path: "../Commander")
-    : .package(url: "https://github.com/steipete/Commander.git", from: "0.2.2")
+let commanderDependency: Package.Dependency = .package(url: "https://github.com/steipete/Commander", from: "0.2.2")
 
 let package = Package(
     name: "Tachikoma",

Sources/Tachikoma/Core/ModelCapabilities.swift

@@ -241,6 +241,7 @@ public final class ModelCapabilityRegistry: @unchecked Sendable {
             excludedParameters: ["temperature", "topP", "frequencyPenalty", "presencePenalty"],
         )
 
+        self.capabilities["openai:chat-latest"] = gpt5Capabilities
         self.capabilities["openai:gpt-5.5"] = gpt5Capabilities
         self.capabilities["openai:gpt-5.4"] = gpt5Capabilities
         self.capabilities["openai:gpt-5.4-mini"] = gpt5Capabilities

Sources/Tachikoma/Core/Types.swift

@@ -186,7 +186,7 @@ public enum OpenAIAPIMode: String, Sendable, CaseIterable {
     public static func defaultMode(for model: LanguageModel.OpenAI) -> OpenAIAPIMode {
         // Determine default API mode for a given model
         switch model {
-        case .gpt5, .gpt5Pro, .gpt5Mini, .gpt5Nano, .gpt54, .gpt54Mini, .gpt54Nano, .gpt55:
+        case .chatLatest, .gpt5, .gpt5Pro, .gpt5Mini, .gpt5Nano, .gpt54, .gpt54Mini, .gpt54Nano, .gpt55:
             .responses // GPT-5 defaults to Responses API
         default:
             .chat // All other models use Chat Completions API

Sources/Tachikoma/Models/Model.swift

@@ -33,6 +33,9 @@ public enum LanguageModel: Sendable, CustomStringConvertible, Hashable {
     // MARK: - Provider Sub-Enums
 
     public enum OpenAI: Sendable, Hashable, CaseIterable {
+        /// Latest ChatGPT Instant alias.
+        case chatLatest
+
         /// GPT-5.5 Series
         case gpt55 // Flagship GPT-5.5
 
@@ -52,6 +55,7 @@ public enum LanguageModel: Sendable, CustomStringConvertible, Hashable {
 
         public static var allCases: [OpenAI] {
             [
+                .chatLatest,
                 .gpt55,
                 .gpt54,
                 .gpt54Mini,
@@ -66,6 +70,7 @@ public enum LanguageModel: Sendable, CustomStringConvertible, Hashable {
         public var modelId: String {
             switch self {
             case let .custom(id): id
+            case .chatLatest: "chat-latest"
             case .gpt55: "gpt-5.5"
             case .gpt54: "gpt-5.4"
             case .gpt54Mini: "gpt-5.4-mini"
@@ -79,7 +84,8 @@ public enum LanguageModel: Sendable, CustomStringConvertible, Hashable {
 
         public var supportsVision: Bool {
             switch self {
-            case .gpt55,
+            case .chatLatest,
+                 .gpt55,
                  .gpt54, .gpt54Mini, .gpt54Nano,
                  .gpt5, .gpt5Pro, .gpt5Mini, .gpt5Nano: true // GPT-5+ supports multimodal
             default: false
@@ -88,7 +94,8 @@ public enum LanguageModel: Sendable, CustomStringConvertible, Hashable {
 
         public var supportsTools: Bool {
             switch self {
-            case .gpt55,
+            case .chatLatest,
+                 .gpt55,
                  .gpt54, .gpt54Mini, .gpt54Nano,
                  .gpt5, .gpt5Pro, .gpt5Mini, .gpt5Nano: true // GPT-5+ excels at tool calling
             case .custom: true // Assume custom models support tools
@@ -120,7 +127,8 @@ public enum LanguageModel: Sendable, CustomStringConvertible, Hashable {
 
         public var contextLength: Int {
             switch self {
-            case .gpt55,
+            case .chatLatest,
+                 .gpt55,
                  .gpt54, .gpt54Mini, .gpt54Nano,
                  .gpt5, .gpt5Pro, .gpt5Mini, .gpt5Nano: 400_000 // 272k input + 128k output
             case .custom: 128_000 // Default assumption
@@ -136,8 +144,7 @@ public enum LanguageModel: Sendable, CustomStringConvertible, Hashable {
                 normalized.hasPrefix("o3") || normalized.hasPrefix("o4") ||
                 normalized.hasPrefix("gpt-5.1") || compact.hasPrefix("gpt51") ||
                 normalized.hasPrefix("gpt-5.2") || compact.hasPrefix("gpt52") ||
-                normalized.contains("gpt-5-thinking") || compact.contains("gpt5thinking") ||
-                normalized == "gpt-5-chat-latest" || compact == "gpt5chatlatest"
+                normalized.contains("gpt-5-thinking") || compact.contains("gpt5thinking")
         }
     }
 
@@ -1114,6 +1121,13 @@ extension LanguageModel {
 
         if let qualified = ProviderParser.parse(trimmed) {
             let provider = qualified.provider.lowercased()
+            if provider == "openai" {
+                guard
+                    let parsed = Self.parse(from: qualified.model),
+                    case .openai = parsed else { return nil }
+
+                return parsed
+            }
             if provider == "openrouter" {
                 return .openRouter(modelId: qualified.model)
             }
@@ -1132,11 +1146,18 @@ extension LanguageModel {
         if
             compact.contains("gpt4") || compact.contains("gpt3") || compact.contains("o3") || compact.contains("o4") ||
             compact.contains("gpt51") || compact.contains("gpt52") ||
-            compact.contains("gpt5thinking") || compact.contains("gpt5chat")
+            compact.contains("gpt5thinking")
         {
             return nil
         }
 
+        if
+            dashed == "chat-latest" || compact == "chatlatest" || dashed == "gpt-5-chat-latest" || compact ==
+            "gpt5chatlatest"
+        {
+            return .openai(.chatLatest)
+        }
+
         if dashed == "gpt-5-pro" || compact == "gpt5pro" {
             return .openai(.gpt5Pro)
         }

Sources/Tachikoma/Models/ModelSelection.swift

@@ -59,6 +59,9 @@ public struct ModelSelector {
 
         if let qualified = ProviderParser.parse(normalized) {
             let provider = qualified.provider.lowercased()
+            if provider == "openai", let openaiModel = parseOpenAIModel(qualified.model.lowercased()) {
+                return .openai(openaiModel)
+            }
             if provider == "openrouter" {
                 return .openRouter(modelId: qualified.model)
             }
@@ -98,6 +101,8 @@ public struct ModelSelector {
 
     private static func parseOpenAIModel(_ input: String) -> Model.OpenAI? {
         switch input {
+        case "chat-latest", "chatlatest", "gpt-5-chat-latest", "gpt5-chat-latest", "gpt5chatlatest":
+            return .chatLatest
         // GPT-5.5 models
         case "gpt-5.5", "gpt5.5", "gpt-5-5", "gpt5-5", "gpt55":
             return .gpt55
@@ -180,8 +185,7 @@ public struct ModelSelector {
             normalized.hasPrefix("o3") || normalized.hasPrefix("o4") ||
             normalized.hasPrefix("gpt-5.1") || normalized.hasPrefix("gpt-5.2") ||
             compact.hasPrefix("gpt51") || compact.hasPrefix("gpt52") ||
-            normalized.contains("gpt-5-thinking") || compact.contains("gpt5thinking") ||
-            normalized == "gpt-5-chat-latest" || compact == "gpt5chatlatest"
+            normalized.contains("gpt-5-thinking") || compact.contains("gpt5thinking")
     }
 
     private static func isUnsupportedLegacyAnthropicModel(_ input: String) -> Bool {

Sources/Tachikoma/Providers/OpenAI/OpenAIResponsesProvider.swift

@@ -58,13 +58,14 @@ public final class OpenAIResponsesProvider: ModelProvider {
         // Set capabilities based on model
         let isReasoningModel = Self.isReasoningModel(model)
         let isGPT5 = Self.isGPT5Model(model)
+        let hasLargeOutputWindow = isReasoningModel || isGPT5 || model == .chatLatest
 
         self.capabilities = ModelCapabilities(
             supportsVision: model.supportsVision,
             supportsTools: model.supportsTools,
             supportsStreaming: true,
             contextLength: model.contextLength,
-            maxOutputTokens: isReasoningModel || isGPT5 ? 128_000 : 4096,
+            maxOutputTokens: hasLargeOutputWindow ? 128_000 : 4096,
         )
     }
 
@@ -263,8 +264,8 @@ public final class OpenAIResponsesProvider: ModelProvider {
                             }
 
                             if let data = jsonString.data(using: .utf8) {
-                                // Try GPT-5 format first
-                                if Self.isGPT5Model(self.model) {
+                                // Responses API event streams use typed event payloads.
+                                if Self.usesResponsesEventStream(self.model) {
                                     if
                                         let event = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                                         let eventType = event["type"] as? String
@@ -939,6 +940,10 @@ public final class OpenAIResponsesProvider: ModelProvider {
             false
         }
     }
+
+    private static func usesResponsesEventStream(_ model: LanguageModel.OpenAI) -> Bool {
+        model == .chatLatest || self.isGPT5Model(model)
+    }
 }
 
 // Configuration extensions removed - properties are immutable for Sendable conformance

Sources/Tachikoma/Providers/ProviderFactory.swift

@@ -17,7 +17,8 @@ public struct ProviderFactory {
         case let .openai(openaiModel):
             // Use Responses API for the GPT-5 family
             switch openaiModel {
-            case .gpt55,
+            case .chatLatest,
+                 .gpt55,
                  .gpt54,
                  .gpt54Mini,
                  .gpt54Nano,

Sources/Tachikoma/Providers/ProviderParser.swift

@@ -227,13 +227,14 @@ public enum ProviderParser {
             !normalized.hasPrefix("o3"), !normalized.hasPrefix("o4"),
             !normalized.hasPrefix("gpt-5.1"), !compact.hasPrefix("gpt51"),
             !normalized.hasPrefix("gpt-5.2"), !compact.hasPrefix("gpt52"),
-            !normalized.contains("gpt-5-thinking"), !compact.contains("gpt5thinking"),
-            normalized != "gpt-5-chat-latest", compact != "gpt5chatlatest" else
+            !normalized.contains("gpt-5-thinking"), !compact.contains("gpt5thinking") else
         {
             return nil
         }
 
         return switch normalized {
+        case "chat-latest", "chatlatest", "gpt-5-chat-latest", "gpt5-chat-latest", "gpt5chatlatest":
+            .openai(.chatLatest)
         case "gpt-5.5", "gpt5.5", "gpt-5-5", "gpt5-5", "gpt55": .openai(.gpt55)
         case "gpt-5.5-mini", "gpt5.5-mini", "gpt-5-5-mini", "gpt5-5-mini", "gpt55-mini", "gpt55mini":
             .openai(.gpt5Mini)

Sources/Tachikoma/Utilities/UsageTracking.swift

@@ -528,6 +528,7 @@ public struct ModelCostCalculator: Sendable {
         // OpenAI Pricing (as of 2025)
         case let .openai(openaiModel):
             switch openaiModel {
+            case .chatLatest: (5.00, 30.00) // ChatGPT Instant alias pricing estimate
             case .gpt55: (5.00, 20.00) // GPT-5.5 pricing estimate
             case .gpt54: (5.00, 20.00) // GPT-5.4 pricing estimate
             case .gpt54Mini: (1.00, 4.00)

Tests/TachikomaTests/Core/ModelCapabilitiesTests.swift

@@ -28,6 +28,13 @@ enum ModelCapabilitiesTests {
             }
         }
 
+        @Test
+        func `chat-latest does not advertise audio input`() {
+            #expect(LanguageModel.openai(.chatLatest).supportsVision)
+            #expect(LanguageModel.openai(.chatLatest).supportsTools)
+            #expect(LanguageModel.openai(.chatLatest).supportsAudioInput == false)
+        }
+
         @Test
         func `Gemini 3 Flash supports thinking config options`() {
             let capabilities = ModelCapabilityRegistry.shared.capabilities(for: .google(.gemini3Flash))

Tests/TachikomaTests/Core/ModelParsingTests.swift

@@ -14,6 +14,15 @@ struct ModelParsingTests {
         #expect(parsed == .openai(.gpt55))
     }
 
+    @Test
+    func `parse chat latest OpenAI alias`() throws {
+        #expect(LanguageModel.parse(from: "chat-latest") == .openai(.chatLatest))
+        #expect(LanguageModel.parse(from: "gpt-5-chat-latest") == .openai(.chatLatest))
+        #expect(LanguageModel.parse(from: "openai/chat-latest") == .openai(.chatLatest))
+        #expect(LanguageModel.parse(from: "openai/gpt-5-chat-latest") == .openai(.chatLatest))
+        #expect(try ModelSelector.parseModel("openai/chat-latest") == .openai(.chatLatest))
+    }
+
     @Test
     func `parse GPT-5.4 base model`() {
         let parsed = LanguageModel.parse(from: "gpt-5.4")

Tests/TachikomaTests/Providers/OpenAIResponsesProviderTests.swift

@@ -23,6 +23,7 @@ struct OpenAIResponsesProviderTests {
         let config = self.openAIConfig()
 
         let gpt5Models: [LanguageModel.OpenAI] = [
+            .chatLatest,
             .gpt55,
             .gpt54,
             .gpt54Mini,
@@ -82,6 +83,7 @@ struct OpenAIResponsesProviderTests {
         let config = self.openAIConfig()
 
         let responsesModels: [LanguageModel.OpenAI] = [
+            .chatLatest,
             .gpt55,
             .gpt54,
             .gpt54Mini,
@@ -245,6 +247,25 @@ struct OpenAIResponsesProviderTests {
         }
     }
 
+    @Test
+    func `chat-latest Responses payload omits GPT-5 reasoning controls`() async throws {
+        let config = TachikomaConfiguration(loadFromEnvironment: false)
+        config.setAPIKey("live-openai", for: .openai)
+
+        try await self.withMockedSession { request in
+            let body = try #require(Self.bodyData(from: request))
+            let json = try JSONSerialization.jsonObject(with: body) as? [String: Any]
+            #expect(json?["model"] as? String == "chat-latest")
+            #expect(json?["reasoning"] == nil)
+            #expect(json?["text"] == nil)
+
+            return NetworkMocking.jsonResponse(for: request, data: Self.responsesPayload(text: "pong"))
+        } operation: { session in
+            let provider = try OpenAIResponsesProvider(model: .chatLatest, configuration: config, session: session)
+            _ = try await provider.generateText(request: self.sampleRequest)
+        }
+    }
+
     @Test
     func `Responses provider resolves OAuth access token`() async throws {
         try await self.withIsolatedAuthState {
@@ -497,6 +518,34 @@ struct OpenAIResponsesProviderTests {
         }
     }
 
+    @Test
+    func `chat-latest streams Responses event deltas`() async throws {
+        let config = TachikomaConfiguration(loadFromEnvironment: false)
+        config.setAPIKey("live-openai", for: .openai)
+
+        try await self.withMockedSession { request in
+            #expect(request.url?.path == "/v1/responses")
+            let payload = Self.responsesStreamPayload(chunks: [
+                Self.streamChunkJSON(content: "Hello", finishReason: nil),
+                Self.streamChunkJSON(content: " latest", finishReason: nil),
+                Self.streamChunkJSON(content: nil, finishReason: "stop"),
+            ])
+            return NetworkMocking.streamResponse(for: request, data: payload)
+        } operation: { session in
+            let provider = try OpenAIResponsesProvider(model: .chatLatest, configuration: config, session: session)
+            let stream = try await provider.streamText(request: self.sampleRequest)
+
+            var collected = ""
+            for try await delta in stream {
+                if case .textDelta = delta.type {
+                    collected.append(delta.content ?? "")
+                }
+            }
+
+            #expect(collected == "Hello latest")
+        }
+    }
+
     private var sampleRequest: ProviderRequest {
         ProviderRequest(
             messages: [ModelMessage(role: .user, content: [.text("ping")])],