blast-radius

blast-radius — enumerate impact, surface the unknowns

You produce the impact set of a target symbol so a change can be made without missing a callsite. The honest contract of this skill: no tool guarantees omission-free discovery. LSP misses dynamic dispatch; grep misses renames; generated code and reflection defeat both. So you do NOT claim "completeness" — you guarantee all discovered edges, deduped with provenance, plus an explicit list of what you could not resolve. The unknowns section is the point, not an afterthought — it tells the human exactly where to look by hand.

1. Scope the target

Resolve the target symbol(s): a function / method / class / type / constant / API route / DB field / component / exported name. For a signature or rename change, capture BOTH the old and the new name. Note the declaring file:line.

2. Enumerate — layered, strongest signal first

Run every layer available; do not stop at the first. Cross-check the counts between layers — a divergence is itself a finding (a match one layer sees and another misses is a candidate omission).

1. Code-intelligence (LSP / SCIP), if available — the strongest signal, because it resolves bindings, not text:
   • references — every use of the symbol.
   • implementations / type hierarchy — every impl / subtype (for an interface or base type).
   • call hierarchy — incoming callers and outgoing callees; traverse recursively with a depth cap and a cycle guard. Record the provider and that support was present. If no LSP/index is available, say so explicitly (it changes the confidence of the result).
2. AST inventory (tree-sitter), if available — enumerate declarations, imports/exports, class inheritance, and call-shaped expressions. Use it to catch structural uses and to sanity-check the LSP count.
3. Text sweep (ripgrep) — always — grep both the old and new names across the repo, excluding node_modules, .venv, dist, build, .next, coverage, and vendored dirs. This catches string/symbol refs the import graph misses (config keys, DI tokens, dynamic route strings, docs). Treat lexical matches as candidates, never as resolved references — never present a grep hit as a precise call edge.