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

Flag	Description
`-f toon`	TOON format (30-60% fewer tokens)
`-w`	Show detailed warnings
`-W`	Treat warnings as errors
`-q`	Quiet mode (no output on success)
`-c`	Include code coverage
`-e`	Include executable targets
`-E`	Exit with failure on build failure
`--build-info`	Per-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 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

•
Build the project:
bash
```
swift build 2>&1 | xcsift -f toon
```
•
If build fails, analyze the structured error output

•

Run tests with coverage:

bash

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

•

For CI pipelines, use strict mode:

bash

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