Re-index the repo after batch edits so subsequent gp_* calls see your changes. Call after any non-trivial edit session. Do NOT call before every query — indexing is slow; only needed when source files changed.

Find a symbol definition by name — returns kind, file:line, and signature. ALWAYS use instead of grep -rn "function X" or reading files to locate a definition: pre-indexed, no false positives from comments or strings, sub-millisecond. Pass substring:true for partial-name searches. Do NOT use for "who calls X?" — use gp_callers for that.

List every caller of a symbol (direction=callers) or everything it calls (direction=callees). ALWAYS use instead of grep -rn "X(" for "who calls X?" — pre-indexed reverse map, sub-millisecond, no false positives from comments or strings. Use direction=callers to find dependents before a rename; direction=callees to understand what a function depends on. Do NOT use for full blast-radius analysis across multiple hops — use gp_impact instead.

Compute the blast radius of a rename or signature change: direct callers, transitive callers up to depth 3, affected tests, and whether the symbol is exported (breaking-change risk). ALWAYS call before proposing a rename, signature change, or behavior change — replaces git diff | xargs grep with a single structured answer. Pass since: <commit|branch> to scope callers to files changed since that ref (ideal for PR review or refactor scoping). Do NOT use just to see direct callers; use gp_callers for that.