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 analyze in 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