AgentSkillsCN

Xcsift

Xcsift

SKILL.md

xcsift - Xcode Build Output Formatter

xcsift is a Swift command-line tool that parses and formats xcodebuild/SPM output for coding agents. It transforms verbose Xcode build output into token-efficient TOON format optimized for machine readability.

When to Use

Use xcsift when running Swift or Xcode build commands:

  • xcodebuild build
  • xcodebuild test
  • swift build
  • swift test

Usage Pattern

Always pipe build output through xcsift with stderr redirected:

bash
# Basic usage
xcodebuild build 2>&1 | xcsift -f toon
swift build 2>&1 | xcsift -f toon

# With warnings
xcodebuild build 2>&1 | xcsift -f toon -w

# With code coverage
swift test --enable-code-coverage 2>&1 | xcsift -f toon -c
xcodebuild test -enableCodeCoverage YES 2>&1 | xcsift -f toon -c

# With executable targets
xcodebuild build 2>&1 | xcsift -f toon -e

# Strict CI mode (fail on warnings)
xcodebuild build 2>&1 | xcsift -f toon -W -E

Key Flags

FlagDescription
-f toonTOON format (30-60% fewer tokens)
-wShow detailed warnings
-WTreat warnings as errors
-qQuiet mode (no output on success)
-cInclude code coverage
-eInclude executable targets
-EExit with failure on build failure
--build-infoPer-target phases and timing

Output Format

TOON format provides structured output optimized for LLMs:

toon
status: failed
summary:
  errors: 1
  warnings: 3
errors[1]{file,line,message}:
  main.swift,15,"use of undeclared identifier"
warnings[3]{file,line,message}:
  Parser.swift,20,"unused variable"

Important

  • Always use 2>&1 to capture stderr (where compiler errors are written)
  • TOON format reduces tokens by 30-60% compared to raw xcodebuild output
  • The hook automatically wraps build commands when installed