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:

# 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

Output Format

TOON format provides structured output optimized for LLMs:

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 Notes

• Always use 2>&1 to capture stderr (where compiler errors are written)
• TOON format reduces tokens by 30-60% compared to raw xcodebuild output
• When running build commands, always add | xcsift -f toon to the end

Example Workflow

1. Build the project:

   swift build 2>&1 | xcsift -f toon
   

2. If build fails, analyze the structured error output

3. Run tests with coverage:

   swift test --enable-code-coverage 2>&1 | xcsift -f toon -c
   

4. For CI pipelines, use strict mode:

   xcodebuild build 2>&1 | xcsift -f toon -W -E