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

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:

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:

swift build 2>&1 | xcsift -f toon

If build fails, analyze the structured error output

Run tests with coverage:

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

For CI pipelines, use strict mode:

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