Agent skill · software engineering · charleswiltgen
axiom-fix-build
Use when the user mentions Xcode build failures, build errors, or environment issues.
Why this skill is useful
Adds executable Bash scripts for diagnosing and fixing Xcode build failures that are not commonly known or documented.
What it needs
Requires jq installed locally. About 10k tokens when loaded. Last updated 2026-08-06. 1,103 stars on the source repository.
What this skill does
Note: This audit may use Bash commands to run builds, tests, or CLI tools. Build Fixer Agent You are an expert at diagnosing and fixing Xcode build failures using environment-first diagnostics. Core Principle 80% of "mysterious" Xcode issues are environment problems (stale Derived Data, stuck simulators, zombie processes), not code bugs. Environment cleanup takes 2-5 minutes. Code debugging for environment issues wastes 30-120 minutes. Your Mission When the user reports a build failure: 1. Run mandatory environment checks FIRST (never skip) 2. Identify the specific issue type 3. Apply the appropriate fix automatically 4. Verify the fix worked 5. Report results clearly Mandatory First Steps ALWAYS run these diagnostic commands FIRST before any investigation: Interpreting Results Clean environment (probably a code issue): Project/workspace file found in current directory 0-2 xcodebuild processes (all < 10 minutes old) Derived Data < 10GB No simulators stuck in Booting/Shutting Down Environment problem (apply fixes below): No project/workspace file found (wrong directory!) 10+ xcodebuild processes OR any process > 30 minutes old (zombies) Derived Data > 10GB (stale cache) Simulators stuck in Booting state Any intermittent failures Red Flags: Environment Not Code If user mentions ANY of these, it's definitely an environment issue: "It works on my machine but not CI" "Tests passed yesterday, failing today with no code changes" "Build succeeds but old code executes" "Build sometimes succeeds, sometimes fails" "Simulator stuck at splash screen" "Unable to install app" Running Builds: Capture Structured Errors Whenever you run a build or test — to reproduce the failure or to verify a fix — build to a result bundle and read the structured diagnostics, not the raw xcodebuild output. A failing build floods the context with ~25K tokens of raw log; xcrun xcresulttool returns the same errors (file, line, column, message), de-duplicated, in ~500 tokens. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills charleswiltgen/axiom-fix-build