Swiftblade — Swift Specialist LoRA

Adapter codename: swiftblade Agent: build-swift Base model: Qwen/Qwen3.5-27B

Objective

Teach the model Swift/Apple-idiomatic code generation aligned with the build-swift agent's system prompt. The adapter should internalize:

Swift 6 strict concurrency (@Sendable, sending, @MainActor)
SwiftUI first, UIKit only when necessary
guard for early exits, proper optional binding
Value types over reference types where appropriate
URLSession for networking (no Alamofire)
swift build → swift test verification cycle
Architecture detection (MVVM, TCA, MV)

Current Status

build-swift currently runs on anthropic/claude-sonnet-4-6 as a quality backstop. The swiftblade adapter is intended as a local replacement, but deployment depends on evaluation results. If quality is insufficient, keep Claude as primary and swiftblade as cost-saving alternative for simple tasks.

Data Sources

Session extraction (~20–40 examples)

Swift sessions are rare. Classify by:

File paths: .swift, Package.swift, *.xcodeproj, project.yml
Bash commands: swift build, swift test, xcodebuild, swift-format
Error patterns: swiftc diagnostics, error:, cannot convert, protocol conformance

Git repo mining (~30–60 examples)

Target repos:

madcat-os/madcat-apple — iOS/macOS app
Any Swift packages in madcat-os org

Extract patterns:

SwiftUI view implementations
@Observable / ObservableObject view model patterns
async/await networking with URLSession
Swift Package Manager configuration
Actor-based state isolation

Synthetic (~80–150 examples)

Swift is the most synthetic-heavy adapter:

Swift 6 concurrency: actors, @Sendable, TaskGroup, structured concurrency
SwiftUI: @State, @Binding, @Environment, custom modifiers
Navigation: NavigationStack, NavigationSplitView, navigation paths
Data flow: @Observable macro (Swift 5.9+), @Bindable
Platform-specific: #available, multi-platform targets
Swift Testing framework (@Test, #expect, @Suite) vs XCTest
Combine → async/await migration patterns
Widget/extension development

Example Format

{
  "messages": [
    {
      "role": "system",
      "content": "<build-swift agent system prompt>"
    },
    {
      "role": "user",
      "content": "Add a settings view with toggle for dark mode and notification preferences"
    },
    {
      "role": "assistant",
      "content": null,
      "tool_calls": [
        {
          "type": "function",
          "function": {
            "name": "glob",
            "arguments": {"pattern": "Sources/**/*.swift"}
          }
        }
      ]
    },
    {
      "role": "tool",
      "content": "<file list showing existing views>"
    },
    {
      "role": "assistant",
      "content": null,
      "tool_calls": [
        {
          "type": "function",
          "function": {
            "name": "read",
            "arguments": {"filePath": "Sources/Views/ContentView.swift"}
          }
        }
      ]
    },
    {
      "role": "tool",
      "content": "<existing SwiftUI view pattern>"
    },
    {
      "role": "assistant",
      "content": null,
      "tool_calls": [
        {
          "type": "function",
          "function": {
            "name": "write",
            "arguments": {
              "filePath": "Sources/Views/SettingsView.swift",
              "content": "import SwiftUI\n\nstruct SettingsView: View {\n    @AppStorage(\"darkMode\") private var darkMode = false\n    ..."
            }
          }
        }
      ]
    },
    {
      "role": "tool",
      "content": "File written"
    },
    {
      "role": "assistant",
      "content": null,
      "tool_calls": [
        {
          "type": "function",
          "function": {
            "name": "bash",
            "arguments": {"command": "swift build 2>&1"}
          }
        }
      ]
    },
    {
      "role": "tool",
      "content": "Build complete!"
    },
    {
      "role": "assistant",
      "content": "SettingsView created. Uses `@AppStorage` for persistence, `Toggle` for dark mode and notifications. Follows existing MVVM pattern. Builds clean."
    }
  ]
}

Evaluation Criteria

swift build passes with no warnings
Swift 6 concurrency: correct @Sendable, actor isolation
SwiftUI-first (no UIKit unless justified)
Proper optional handling (guard let, if let, no force-unwrap)
Value types where appropriate
Architecture matches project (MVVM/TCA/MV detection)
Tool call sequence: explore → read patterns → implement → build → test

Training Config Overrides

MAX_SEQ = 8192
LR      = 5e-5

Estimated Size

100–200 examples (mostly synthetic)
~0.8M tokens
Training time: ~1 hr on H100
Adapter size: ~305 MB

Risk: Quality Gap vs Claude

Claude Sonnet excels at Swift due to Apple's partnership data. Swiftblade on Qwen3.5-27B may underperform on:

Complex generics and associated types
Protocol-oriented design patterns
Platform-specific API knowledge (Core Data, CloudKit, etc.)

Mitigation: keep Claude as fallback, use swiftblade for simpler tasks (UI, boilerplate, tests). Evaluate before full switchover.

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