coding

name	coding
description	Navigate large codebases and make surgical edits while following project conventions. Use for refactors, feature work, and bug fixes spanning multiple files.

Coding skill

When to use

• User asks to implement a feature, fix a bug, or refactor code across multiple files
• User asks to navigate and understand a large codebase
• User asks for a code review or asks what a piece of code does
• User asks to add tests for existing code

When NOT to use

• The task is only running a test suite — use testing skill
• The task is only a git operation — use git-workflow skill
• The task is scripting a one-off data transform — use data-analysis skill

Procedure

1. Locate the project root: find build file (pyproject.toml, package.json, Cargo.toml, go.mod, Makefile).
2. Search before editing: use search_files to find relevant symbols, functions, or patterns.
3. Read full files before editing: read_file must see the full file before edit_file is called (tracker enforces this).
4. Plan the change: state which files change and why before making edits.
5. Make surgical edits: use edit_file with multi-line old_text for unique matches. Use write_file only for new files or full rewrites.
6. Verify: run the project's build/check command or tests after editing.
7. Match existing style: indentation, naming, comment density — copy from surrounding code, don't introduce new conventions.

Recipes

Find where a function is defined:

search_files(pattern="def my_function", path="/project/src")

Find all callers of a function:

search_files(pattern="my_function(", path="/project")

Read a file in sections (large file):

read_file(path="/project/src/module.py", limit=100)           # first 100 lines
read_file(path="/project/src/module.py", offset=100, limit=100)  # next 100

Multi-line edit (unique match): Use enough surrounding context so old_text appears exactly once in the file.

Check for syntax errors (Python):

python3 -m py_compile /path/to/file.py && echo OK

Check for syntax errors (Go):

go vet ./...

Check for syntax errors (Rust):

cargo check

Check for syntax errors (Node):

node --check /path/to/file.js

Pitfalls

• Never edit a file you haven't fully read — the FileReadTracker will block edit_file on partially-read files.
• After 2 edit_file failures on the same file, switch to write_file (full rewrite).
• Never guess at what a function does from its name — read the implementation.
• Avoid adding dependencies without user approval.
• Never declare a bug fixed without running a verification step.
• Watch for double-nesting: verify directory paths with list_directory before writing.

References

• references/python.md — Python idioms, test commands, common gotchas
• references/javascript.md — JS/TS idioms, test commands, ESM vs CJS
• references/go.md — Go idioms, test commands, module layout
• references/rust.md — Rust idioms, test commands, cargo workflow