Use this skill ANY time you need to search for code structure, refactor symbols, analyze impact, find dead code, or trace dependencies. ALWAYS invoke BEFORE using grep for structural code analysis. Trigger categories: structural pattern search (e.g. useEffect without deps, async without try-catch, fetch calls outside src/api), bulk code migration/transformation (wrap handlers, replace API calls), dependency & impact analysis (blast radius, transitive deps, which modules depend on X), safe renaming across codebases, dead code & circular import detection, ast-grep rule authoring. Trigger keywords: try-catch, useEffect, async without, circular imports, safe rename, blast radius, bulk migration, never imported, unused exports, ast-grep, enforce pattern, structural search, depends on, which modules. Do NOT trigger for: grep-able string searches, file-name lookups, reading READMEs, writing regex, CSV/data scripts.
Use this skill for any structural code search or replacement task — it is the right choice whenever grep/sed would feel clunky or risky. Trigger on ANY of these patterns: **Structural find-and-replace across a codebase:** "replace all fetch(url, options) calls with the new fetchWithRetry signature", "rename the first argument of every logger.log call from msg to message", "swap the argument order of this helper across all files" **Cross-language or multi-format refactoring:** "update this API pattern in all .js and .ts files", "change all SQL SELECT * to SELECT col1, col2 in our query templates", "modernize these HTML button attributes" **Code migration / deprecated API patterns:** "migrate all createStore() calls to configureStore()", "update all axios.get(url) to the new axios({url, method}) form", "Python 2 print statements to Python 3 print() functions across the whole project", "modernize old Python 2 idioms to Python 3" **Safe multi-file replacements that regex would botch:** multiline expressions, nest
Execute this meta-skill ALWAYS at the end of complex tasks, debugging sessions, or when learning a new project codebase quirk. You MUST trigger this skill to codify hard-won lessons into reusable project rules (saving them to project-specific AI instruction files or a new SKILL.md). Do NOT close a complex task without running this skill to ensure future agents don't make the same mistakes you did!
Trigger this AUTOMATICALLY anytime you encounter a stack trace, test failure, production bug, or unexpected behavior. Do NOT guess the fix or propose code changes before explicitly triggering this skill. This skill mandates a strict data-gathering and hypothesis phase before you are permitted to edit ANY source code.