Before you edit
Check blast radius and test impact before changing unfamiliar code.
Know what depends on a file — and which tests cover it — before you touch it.
prism blast src/auth/session.ts
prism test-impact src/auth/session.ts
prism blast src/auth/session.ts --fail-on highWhat you get back
- Direct and transitive dependents — files that would notice a change.
- Affected tests and features — what to run and what user-facing area moves.
- Risk band — Low / Moderate / High from a 0–100 score. Higher means more risk. See risk bands.
Static analysis is a floor, not a complete call graph: dynamic imports and runtime DI are invisible.
When this is wrong
- Path outside the workspace is refused (not clamped).
- Underestimate when coupling is string-keyed or reflective — treat the band as a lower bound.
- Blast radius does not know if your edit is breaking; identical radius for adding an optional param vs deleting an export.