tomevault-io 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 testswift build/swift test- Any command that produces Xcode/SPM build output
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:succeededorfailederrors[N]{columns}:— tabular array with N items, column names in braceswarningshavetype:compile,runtime, orswiftuifailed_testsinclude file/line for navigation and durationnullvalues mean the data wasn't available (e.g.,build_time: nullif not parsed)
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 swift build -c release && cp .build/release/xcsift /usr/local/bin/ |
| 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>&1to capture stderr (compiler errors and warnings go to stderr) - TOON format reduces tokens by 30-60% compared to raw xcodebuild output
- The pre-tool hook automatically wraps build commands when the plugin is installed
- Flaky test detection is automatic (no flag needed) — detects tests that both pass and fail
Source: ldomaradzki/xcsift — distributed by TomeVault.