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. gitnexus_impact({target: "X", direction: "upstream"}) → What depends on this 2. READ gitnexus://repo/{name}/processes → Check affected execution flows 3. gitnexus_detect_changes() → Map current git changes to affected flows 4. Assess risk and report to user
If "Index is stale" → run
npx gitnexus analyzein terminal.
Checklist
- [ ] gitnexus_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 - [ ] gitnexus_detect_changes() for pre-commit check - [ ] Assess risk level and report to user
Understanding 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
gitnexus_impact — the primary tool for symbol blast radius:
gitnexus_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%]
gitnexus_detect_changes — git-diff based impact analysis:
gitnexus_detect_changes({scope: "staged"}) → Changed: 5 symbols in 3 files → Affected: LoginFlow, TokenRefresh, APIMiddlewarePipeline → Risk: MEDIUM
Example: "What breaks if I change validateUser?"
1. gitnexus_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
