File Analysis Skill for Claude

File Analysis

When To Use

• Before architecture reviews to understand module boundaries and file organization.
• When exploring unfamiliar codebases to map structure before making changes.
• As input to scope estimation for refactoring or migration work.

When NOT To Use

• General code exploration - use the Explore agent
• Searching for specific patterns - use Grep directly

Required TodoWrite Items

• file-analysis:root-identified
• file-analysis:structure-mapped
• file-analysis:patterns-detected
• file-analysis:hotspots-noted

Mark each item as complete as you finish the corresponding step.

Step 1: Identify Root (file-analysis:root-identified)

• Confirm the analysis root directory with pwd.
• Note any monorepo boundaries, workspace roots, or subproject paths.
• Capture the project type (language, framework) from manifest files (package.json, Cargo.toml, pyproject.toml, etc.).

Step 2: Map Structure (file-analysis:structure-mapped)

• Run tree -L 2 -d or find . -type d -maxdepth 2 to capture the top-level directory layout.
• Identify standard directories: src/, lib/, tests/, docs/, scripts/, configs/.
• Note any non-standard organization patterns that may affect downstream analysis.

Step 3: Detect Patterns (file-analysis:patterns-detected)

• Use find . -name "*.ext" -not -path "*/.venv/*" -not -path "*/__pycache__/*" -not -path "*/node_modules/*" -not -path "*/.git/*" | wc -l to count files by extension.
• Identify dominant languages and their file distributions.
• Note configuration files, generated files, and vendored dependencies.
• Run wc -l $(find . -not -path "*/.venv/*" -not -path "*/__pycache__/*" -not -path "*/node_modules/*" -not -path "*/.git/*" -name "*.py" -o -name "*.rs" | head -20) to sample file sizes.

Step 4: Note Hotspots (file-analysis:hotspots-noted)

• Identify large files (potential "god objects"): find . -type f -exec wc -l {} + | sort -rn | head -10.
• Flag deeply nested directories that may indicate complexity.
• Note files with unusual naming conventions or placement.

Exit Criteria

• TodoWrite items are completed with concrete observations.
• Downstream workflows (architecture review, refactoring) have structural context.
• File counts, directory layout, and hotspots are documented for reference.