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 score language-migration settings like SWIFT_STRICT_CONCURRENCY or SWIFT_UPCOMING_FEATURE_* as performance findings. They are enforced by the project baseline (lacquer audit, CI Baseline job) instead.
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 outputsDEFINES_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
Source: AvdLee/Xcode-Build-Optimization-Agent-Skill, adapted.
1---2name: xcode-project-analyzer3description: Audit Xcode project configuration, build settings, scheme behavior, and script phases to find build-time improvements with explicit approval gates. Use when a developer wants project-level build analysis, slow incremental builds, guidance on target dependencies, build settings review, run script phase analysis, parallelization improvements, or module-map and DEFINES_MODULE configuration.4---56# Xcode Project Analyzer78Use this skill for project- and target-level build inefficiencies that are unlikely to be solved by source edits alone.910## Core Rules1112- Recommendation-first by default.13- Require explicit approval before changing project files, schemes, or build settings.14- Prefer measured findings tied to timing summaries, build logs, or project configuration evidence.15- Distinguish debug-only pain from release-only pain.1617## What To Review1819- scheme build order and target dependencies20- debug vs release build settings against the [build settings best practices](references/build-settings-best-practices.md)21- run script phases and dependency-analysis settings22- derived-data churn or obviously invalidating custom steps23- opportunities for parallelization24- explicit module dependency settings and module-map readiness25- "Planning Swift module" time in the Build Timing Summary -- if it dominates incremental builds, suspect unexpected input modification or macro-related invalidation26- asset catalog compilation time, especially in targets with large or numerous catalogs27- `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)28- zero-change build overhead -- if a no-op rebuild exceeds a few seconds, investigate fixed-cost phases (script execution, codesign, validation, CopySwiftLibs)29- 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](references/project-audit-checks.md))30- Task Backtraces (Xcode 16.4+: Scheme Editor > Build > Build Debugging) to diagnose why tasks re-run unexpectedly in incremental builds3132## Build Settings Best Practices Audit3334Every 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](references/build-settings-best-practices.md). Present results using checkmark/cross indicators (`[x]`/`[ ]`). The scope is strictly build performance -- do not score language-migration settings like `SWIFT_STRICT_CONCURRENCY` or `SWIFT_UPCOMING_FEATURE_*` as performance findings. They are enforced by the project baseline (`lacquer audit`, CI `Baseline` job) instead.3536## Apple-Derived Checks3738Review these items in every audit:3940- target dependencies are accurate and not missing or inflated41- schemes build in `Dependency Order`42- run scripts declare inputs and outputs43- `.xcfilelist` files are used when scripts have many inputs or outputs44- `DEFINES_MODULE` is enabled where custom frameworks or libraries should expose module maps45- headers are self-contained enough for module-map use46- explicit module dependency settings are consistent for targets that should share modules4748## Typical Wins4950- skip debug-time scripts that only matter in release51- add missing script guards or dependency-analysis metadata52- remove accidental serial bottlenecks in schemes53- align build settings that cause unnecessary module variants54- fix stale project structure that forces broader rebuilds than necessary55- identify linters or formatters that touch file timestamps without changing content, silently invalidating build inputs and forcing module replanning56- split large asset catalogs into separate resource bundles across targets to parallelize compilation57- use Task Backtraces to pinpoint the exact input change that triggers unnecessary incremental work5859## Reporting Format6061For each issue, include:6263- evidence64- likely scope65- why it affects clean builds, incremental builds, or both66- estimated impact67- approval requirement6869If the evidence points to package graph or build plugins, hand off to [`spm-build-analysis`](../spm-build-analysis/SKILL.md) by reading its SKILL.md and applying its workflow to the same project context.7071## Additional Resources7273- For the detailed audit checklist, see [references/project-audit-checks.md](references/project-audit-checks.md)74- For build settings best practices, see [references/build-settings-best-practices.md](references/build-settings-best-practices.md)75- For the shared recommendation structure, see [references/recommendation-format.md](references/recommendation-format.md)76- For Apple-aligned source summaries, see [references/build-optimization-sources.md](references/build-optimization-sources.md)7778Source: [AvdLee/Xcode-Build-Optimization-Agent-Skill](https://github.com/AvdLee/Xcode-Build-Optimization-Agent-Skill), adapted.
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