code-deduplication

Maintain a CODE_INDEX.md file organized by capability that lists each function's location, purpose, and parameters. Before writing any new function, search the index and codebase for similar functionality, then reuse or extend existing code instead of reimplementing it.

A capability index is a Markdown file organized by what code does rather than where it lives. It groups functions into categories like Date/Time, Validation, and API Clients, with tables showing function name, file location with line number, plain-English purpose, and parameters.

Use a vector database like ChromaDB or LanceDB when a codebase exceeds roughly 200 files and a Markdown index becomes hard to search. For under 50 files a Markdown index alone suffices, and 50-200 files work with an index plus periodic audits.

Run a structured audit checking utility functions, API calls, validation logic, error handling, components, and hooks for overlap. Report findings by priority: high-priority items to merge immediately, medium-priority patterns to consolidate, and low-priority items to monitor.

A Markdown index requires manual or assisted updates after every code change and becomes unwieldy past a few hundred files. It also relies on keyword matching, so semantically similar functions with different naming may be missed without vector search.