/xcsift

name: xcsift
description: Use xcsift for all Swift and Xcode build commands. Pipe xcodebuild build, xcodebuild test, swift build, swift test through xcsift for structured TOON output with compile errors, warnings, test failures, code coverage, slow tests, and build timing. Essential for parsing Xcode build output, diagnosing compile errors, analyzing test results, and measuring code coverage in any Swift or Xcode project.

xcsift - Xcode Build Output Formatter

xcsift parses and formats xcodebuild/SPM output into token-efficient TOON format optimized for LLM consumption. It extracts compile errors, warnings, test failures, code coverage, and build timing from verbose Xcode output.

When to Use

**Always** pipe through xcsift when running:

• `xcodebuild build` / `xcodebuild test`
• `swift build` / `swift test`
• Any command that produces Xcode/SPM build output

When Not to Use

Informational commands print an answer, not a build log. xcsift discards that answer, so run them directly:

• `xcodebuild -version` / `-usage` / `-help`
• `xcodebuild -list` / `-showsdks` / `-showdestinations` / `-showTestPlans` / `-showBuildSettings`
• `xcodebuild -find-executable` / `-find-library` / `-create-xcframework`
• `swift build --show-bin-path`, `swift test --list-tests`, and any `--help` or `--version` command

Usage Pattern

Always redirect stderr and use TOON format:

# Build
xcodebuild build 2>&1 | xcsift -f toon
swift build 2>&1 | xcsift -f toon

# Test
swift test 2>&1 | xcsift -f toon
xcodebuild test 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 detailed per-file coverage
swift test --enable-code-coverage 2>&1 | xcsift -f toon -c --coverage-details

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

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

# Slow test detection
swift test 2>&1 | xcsift -f toon --slow-threshold 1.0

# Build info (per-target phases, timing, dependencies)
xcodebuild build 2>&1 | xcsift -f toon --build-info

Key Flags

| Flag | Description | |------|-------------| | `-f toon` | TOON format (30-60% fewer tokens than JSON) | | `-w` | Show detailed warnings list | | `-W` | Treat warnings as errors (Werror) | | `-q` | Quiet mode (no output on clean success) | | `-c` | Include code coverage summary | | `--coverage-details` | Per-file coverage breakdown (use with `-c`) | | `-e` | Include executable targets | | `-E` | Exit with non-zero code on build failure | | `--build-info` | Per-target phases, timing, and dependencies | | `--slow-threshold N` | Flag tests slower than N seconds | | `--config PATH` | Use custom config file (default: `.xcsift.toml`) | | `--init` | Generate `.xcsift.toml` template in current directory |

Interpreting TOON Output

TOON uses indentation-based structure with tabular arrays:

status: failed
summary:
  errors: 1
  warnings: 3
  failed_tests: 2
  passed_tests: 10
  build_time: 12.4s
  test_time: 5.2s
errors[1]{file,line,message}:
  main.swift,15,"use of undeclared identifier 'foo'"
warnings[3]{file,line,message,type}:
  Parser.swift,20,"unused variable 'result'",compile
  View.swift,42,"Publishing changes from background threads",swiftui
  Util.swift,10,"Custom warning message",runtime
failed_tests[2]{suite,test,file,line,message,duration}:
  MyTests,testExample,MyTests.swift,25,"XCTAssertEqual failed",0.123
  MyTests,testOther,MyTests.swift,30,"XCTAssertTrue failed",0.456

**Key patterns:**

• `status`: `succeeded` or `failed`
• `errors[N]{columns}:` — tabular array with N items, column names in braces
• `warnings` have `type`: `compile`, `runtime`, or `swiftui`
• `failed_tests` include file/line for navigation and duration
• `null` values mean the data wasn't available

Troubleshooting

| Problem | Solution | |---------|----------| | No errors shown but build failed | Add `2>&1` to capture stderr | | Coverage shows `null` | Add `--enable-code-coverage` (SPM) or `-enableCodeCoverage YES` (xcodebuild) | | "xcsift not found" | Install: `brew install xcsift` or build from source | | Coverage for wrong target | xcsift auto-filters to tested target; use `--coverage-path` to override | | Config not loading | Check `.xcsift.toml` in CWD or `~/.config/xcsift/config.toml` |

Important

• **Always use `2>&1`** to capture stderr (compiler errors and warnings go to stderr)
• TOON format reduces tokens by 30-60% compared to raw xcodebuild output
• When running build commands, always add `| xcsift -f toon` to the end
• Flaky test detection is automatic (no flag needed) — detects tests that both pass and fail