Platform Detection Engine

Runs once at the start of any feature-marker workflow and caches the result. All subsequent phases read from the cached platform-context.json — never re-detect.

When to run

• First time: Phase 0 (Inputs Gate) if platform-context.json does not exist in state dir
• Skip: If platform-context.json already exists — use the cached result
• Force re-detect: If user passes --redetect or deletes the file manually

Detection logic

Scan the project root for the following signals, in priority order:

🍎 iOS / Swift

Detected when ANY of:

• *.xcodeproj found (up to 3 levels deep)
• *.xcworkspace found (up to 3 levels deep)
• Package.swift found in root

Subtype disambiguation:

• xcworkspace → CocoaPods/multi-target workspace
• xcodeproj → single Xcode project
• swift-package → Swift Package Manager (Package.swift, no .xcodeproj)

iOS confirmation (vs macOS/watchOS):

• IPHONEOS_DEPLOYMENT_TARGET in any .pbxproj
• UIRequiredDeviceCapabilities in any Info.plist

Test framework detection:

• Any *Tests.swift with import Testing → swift-testing
• Only import XCTest in test files → xctest
• No test files → default to swift-testing

Tool availability checks:

• command -v swiftlint → capabilities.swiftlint_available
• ~/.claude/skills/xcodebuildmcp/SKILL.md exists → capabilities.xcodebuildmcp_available

🟨 Node.js / TypeScript

Detected when: package.json exists in root

Package manager detection from lockfiles:

• pnpm-lock.yaml → pnpm
• yarn.lock → yarn
• bun.lockb → bun
• package-lock.json or none → npm

Subtype:

• next.config.{js,ts,mjs} → nextjs
• react-native in package.json deps → react-native
• nest-cli.json → nestjs
• else → node

Test runner:

• jest.config.{js,ts} or "jest" in package.json → jest
• vitest.config.{ts,js} or "vitest" in package.json → vitest
• else → {pm} test

🦀 Rust

Detected when: Cargo.toml exists in root

🐍 Python

Detected when ANY of: pyproject.toml, setup.py, requirements.txt

🐹 Go

Detected when: go.mod exists in root

Multi-stack / Monorepo

If signals from 2+ platforms detected → set is_monorepo: true. Map each detected platform to its sub-directory when possible.

Manual override

Check .feature-marker.json for manual platform override:

{ "platform": "ios" }

If present, use that as primary_platform (overrides auto-detection).

Output: platform-context.json

Save to .claude/feature-state/{slug}/platform-context.json:

{
  "primary_platform": "ios",
  "platforms": [
    {
      "type": "ios",
      "subtype": "swift-package",
      "path": ".",
      "confidence": "high",
      "signals": ["Package.swift found", ".swift files present (47)", "IPHONEOS_DEPLOYMENT_TARGET detected"],
      "test_command": "swift test --parallel",
      "build_command": "xcodebuild build",
      "lint_command": "swiftlint",
      "test_framework": "swift-testing",
      "capabilities": {
        "swiftlint_available": true,
        "xcodebuildmcp_available": true,
        "swift_testing_available": true
      }
    }
  ],
  "is_monorepo": false,
  "detected_at": "2026-03-01T12:00:00Z"
}

Node.js example:

{
  "primary_platform": "nodejs",
  "platforms": [
    {
      "type": "nodejs",
      "subtype": "nextjs",
      "path": ".",
      "confidence": "high",
      "signals": ["package.json found", "next.config found", "pnpm-lock.yaml found"],
      "package_manager": "pnpm",
      "package_manager_lock": "pnpm-lock.yaml",
      "test_command": "jest --findRelatedTests",
      "build_command": "pnpm run build",
      "lint_command": "pnpm run lint"
    }
  ],
  "is_monorepo": false,
  "detected_at": "2026-03-01T12:00:00Z"
}

Confidence scoring

User output

After detection, always display:

✅ Platform detected: iOS (Swift Package) — swift test + SwiftLint + XcodeBuildMCP

Or for Node.js:

✅ Platform detected: Node.js / Next.js (pnpm) — jest + pnpm run lint

If unknown:

⚠️ Platform not detected. No known config files found.
   Running without platform-specific commands. Use .feature-marker.json to override.

Usage by other phases