Impact Analysis with GitNexus
When to Use
- "Is it safe to change this function?"
- "What will break if I modify X?"
- "Show me the blast radius"
- "Who uses this code?"
- Before making non-trivial code changes
- Before committing — to understand what your changes affect
Workflow
1. impact({target: "X", direction: "upstream"}) → What depends on this
2. READ gitnexus://repo/{name}/processes → Check affected execution flows
3. detect_changes() → Map current git changes to affected flows
4. Assess risk and report to userIf "Index is stale" → run
node .gitnexus/run.cjs analyzein terminal.
Checklist
- [ ] impact({target, direction: "upstream"}) to find dependents
- [ ] Review d=1 items first (these WILL BREAK)
- [ ] Check high-confidence (>0.8) dependencies
- [ ] READ processes to check affected execution flows
- [ ] detect_changes() for pre-commit check
- [ ] Assess risk level and report to userUnderstanding Output
| Depth | Risk Level | Meaning |
|---|---|---|
| d=1 | WILL BREAK | Direct callers/importers |
| d=2 | LIKELY AFFECTED | Indirect dependencies |
| d=3 | MAY NEED TESTING | Transitive effects |
Risk Assessment
| Affected | Risk |
|---|---|
| <5 symbols, few processes | LOW |
| 5-15 symbols, 2-5 processes | MEDIUM |
| >15 symbols or many processes | HIGH |
| Critical path (auth, payments) | CRITICAL |
Tools
impact — the primary tool for symbol blast radius:
impact({
target: "validateUser",
direction: "upstream",
minConfidence: 0.8,
maxDepth: 3
})
→ d=1 (WILL BREAK):
- loginHandler (src/auth/login.ts:42) [CALLS, 100%]
- apiMiddleware (src/api/middleware.ts:15) [CALLS, 100%]
→ d=2 (LIKELY AFFECTED):
- authRouter (src/routes/auth.ts:22) [CALLS, 95%]detect_changes — git-diff based impact analysis:
detect_changes({scope: "staged"})
→ Changed: 5 symbols in 3 files
→ Affected: LoginFlow, TokenRefresh, APIMiddlewarePipeline
→ Risk: MEDIUMExample: "What breaks if I change validateUser?"
1. impact({target: "validateUser", direction: "upstream"})
→ d=1: loginHandler, apiMiddleware (WILL BREAK)
→ d=2: authRouter, sessionManager (LIKELY AFFECTED)
2. READ gitnexus://repo/my-app/processes
→ LoginFlow and TokenRefresh touch validateUser
3. Risk: 2 direct callers, 2 processes = MEDIUM
