Assess Impact
HARD GATE — Run this skill before
plan-workwhenever a change touches an existing module, symbol, or file used by more than one caller. Skip only for net-new code with no existing dependents.
Find the blast radius of the proposed change before a single line is written.
Modes
- Default: full impact analysis (dependents + affected stories + test coverage mapping)
- --lightweight: Fast fan-in/fan-out only (<10s). Maps callers and imports without test coverage mapping. Used by build-epic step 2 as a pre-plan gate. Risk score > 7 triggers a mandatory grill-me session before proceeding.
Process
1. Identify the target
Name the symbol, module, or file being changed. If the user hasn't specified, ask one question: "What exactly are you changing?"
2. Find dependents
grep -rn "[symbol-name]" . --include="*.ts" | grep -v node_modules git log --oneline -10 -- [file-path]
→ verify: test -f specs/IMPACT_LATEST.md || test -d specs/bugs
3. Map to release plan stories
Read specs/release-plan.yaml + epic capsule directories (if it exists). For each dependent found in Step 2, identify which story owns that module. List stories that will be affected by the change.
→ verify: test -f specs/release-plan.yaml && grep -ci "stor" specs/release-plan.yaml
4. List test coverage
Find tests that exercise the target:
grep -rn "[symbol-name]" . --include="*.test.*" --include="*.spec.*"
→ verify: test -d specs/epics || test -d skills
5. Classify risk
| Level | Condition |
|---|---|
| Low | ≤ 2 callers, all covered by tests |
| Medium | 3–10 callers, partial test coverage |
| High | > 10 callers, or shared API/interface, or no tests |
6. Write specs/IMPACT_LATEST.md
## Target [symbol or file being changed] ## Dependents ([count]) - [file]: [caller or usage] ## Affected Stories - Story [X.Y]: [title] ## Test Coverage - [test file]: covers [scenario] - Gap: [untested behavior] ## Risk: Low / Medium / High [One-sentence rationale] ## Recommended action [Proceed / Add tests first / Discuss design]
→ verify: grep "Risk:" specs/IMPACT_LATEST.md
Suggest plan-work once risk is understood and any test gaps are noted.
Risk score gating
In --lightweight mode (used by build-epic step 2), assign a numeric risk score (1–10):
- Fan-in (how many callers): 0–4 points
- Fan-out (how many dependencies the module itself uses): 0–3 points
- Recent churn (git log --oneline -5 count): 0–3 points
Risk score > 7: Gate — require a grill-me session before proceeding to implementation. Document the grill-me result in the impact report at specs/IMPACT-<epic>-<story>.md.
