Deterministic code navigation for Pi — three tools built on tree-sitter + SQLite that answer common exploration questions in one call instead of chains of rg + read.
def(name)— return a function/class/method/type body as one unit, with file path and precise line range.callers(name)— find every syntactic call site for a symbol via AST traversal.outline(file)— list symbols in a file or directory, with kind and line range. Nested members (e.g. class methods, interface members, inner types) are shown indented under their parents.
- Indexer (
src/indexer.ts) walks the repo, parses files, and extracts symbols & calls via tree-sitter tag queries. - Database (
src/db.ts) stores the graph in SQLite (in-memory), so structural queries are just JOINs. - File watcher (chokidar) keeps the index in sync after the initial startup re-index.
Currently supported languages: TypeScript/TSX, Python, Rust.
Both can answer the same questions, but with different accuracy-vs-availability trade-offs.
LSP gives semantically correct answers. It follows imports, resolves aliases, and respects type boundaries, so callers is accurate even when the same name is used in different modules or overloaded on different types. The cost is operational: one server per language, cold-start latency, stateful connections, and failure modes when the code does not compile or the server crashes.
Tree-sitter gives syntactically approximate answers instantly. It parses files in milliseconds, works on broken code, and uses the same library for every language. The downside is that cross-file relationships (imports, aliases, type-based dispatch) are invisible unless you rebuild a subset of the language's semantics yourself.
For def and outline the two approaches are roughly equivalent. For callers, LSP is strictly more accurate — but its answers can lag behind the file on disk, and it needs a compiling build and a running server. Tree-sitter reads exactly what is there, instantly. We chose predictability and zero-config operability over semantic precision.
- Syntax-tree navigation only — no LSP, no type resolution.
callersdoes not trace variable reassignments or resolve dynamic dispatch.