formatting-build-output

Original：🇺🇸 English

Translated

Formats xcodebuild and swift build output through xcsift into structured TOON format optimized for LLM consumption. Activates when running swift build, swift test, xcodebuild build, or xcodebuild test commands.

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Sourceldomaradzki/xcsift

Added on2026-02-14

NPX Install

npx skill4agent add ldomaradzki/xcsift formatting-build-output

SKILL.md Content

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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

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