Xcode Project Analyzer Agent Skill

Xcode Project Analyzer

Use this skill for project- and target-level build inefficiencies that are unlikely to be solved by source edits alone.

Core Rules

• Recommendation-first by default.
• Require explicit approval before changing project files, schemes, or build settings.
• Prefer measured findings tied to timing summaries, build logs, or project configuration evidence.
• Distinguish debug-only pain from release-only pain.

What To Review

• scheme build order and target dependencies
• debug vs release build settings against the build settings best practices
• run script phases and dependency-analysis settings
• derived-data churn or obviously invalidating custom steps
• opportunities for parallelization
• explicit module dependency settings and module-map readiness
• "Planning Swift module" time in the Build Timing Summary -- if it dominates incremental builds, suspect unexpected input modification or macro-related invalidation
• asset catalog compilation time, especially in targets with large or numerous catalogs
• ExtractAppIntentsMetadata time in the Build Timing Summary -- if this phase consumes significant time, record it as xcode-behavior (report the cost and impact, but do not suggest a repo-local optimization unless there is explicit Apple guidance)
• zero-change build overhead -- if a no-op rebuild exceeds a few seconds, investigate fixed-cost phases (script execution, codesign, validation, CopySwiftLibs)
• CocoaPods usage -- if a Podfile or Pods.xcodeproj exists, CocoaPods is deprecated; recommend migrating to SPM and do not attempt CocoaPods-specific optimizations (see project-audit-checks.md)
• Task Backtraces (Xcode 16.4+: Scheme Editor > Build > Build Debugging) to diagnose why tasks re-run unexpectedly in incremental builds

Build Settings Best Practices Audit

Every project audit should include a build settings checklist comparing the project's Debug and Release configurations against the recommended values in build-settings-best-practices.md. Present results using checkmark/cross indicators ([x]/[ ]). The scope is strictly build performance -- do not flag language-migration settings like SWIFT_STRICT_CONCURRENCY or SWIFT_UPCOMING_FEATURE_*.

Apple-Derived Checks

Review these items in every audit:

• target dependencies are accurate and not missing or inflated
• schemes build in Dependency Order
• run scripts declare inputs and outputs
• .xcfilelist files are used when scripts have many inputs or outputs
• DEFINES_MODULE is enabled where custom frameworks or libraries should expose module maps
• headers are self-contained enough for module-map use
• explicit module dependency settings are consistent for targets that should share modules

Typical Wins

• skip debug-time scripts that only matter in release
• add missing script guards or dependency-analysis metadata
• remove accidental serial bottlenecks in schemes
• align build settings that cause unnecessary module variants
• fix stale project structure that forces broader rebuilds than necessary
• identify linters or formatters that touch file timestamps without changing content, silently invalidating build inputs and forcing module replanning
• split large asset catalogs into separate resource bundles across targets to parallelize compilation
• use Task Backtraces to pinpoint the exact input change that triggers unnecessary incremental work

Reporting Format

For each issue, include:

• evidence
• likely scope
• why it affects clean builds, incremental builds, or both
• estimated impact
• approval requirement

If the evidence points to package graph or build plugins, hand off to spm-build-analysis by reading its SKILL.md and applying its workflow to the same project context.

Additional Resources

• For the detailed audit checklist, see references/project-audit-checks.md
• For build settings best practices, see references/build-settings-best-practices.md
• For the shared recommendation structure, see references/recommendation-format.md
• For Apple-aligned source summaries, see references/build-optimization-sources.md