gitnexus-impact

name	gitnexus-impact
description	Blast radius analysis — what breaks if you change a symbol. Triggers: "impact analysis" | "what breaks if" | "blast radius" | "gitnexus impact" | "is it safe to change" | "dependencies of".

GitNexus Impact

Blast radius analysis: find what breaks if you change a symbol. Essential before refactoring.

Entry

/gitnexus-impact validateUser
/gitnexus-impact AuthService --direction downstream
/gitnexus-impact processOrder --depth 2

¬symbol → ask user provide a symbol name.

Step 0 — Pre-flight

gitnexus status

¬indexed → ask user run /gitnexus-analyze first.

Step 1 — Run Impact Analysis

gitnexus impact "$SYMBOL" $FLAGS

Flag	Effect
--direction upstream	Who depends on this (default)
--direction downstream	What this depends on
--depth N	Max relationship depth (default: 3)
--include-tests	Include test files
--repo <name>	Target specific repo

Step 2 — Parse JSON Output

{
  "target": "validateUser",
  "direction": "upstream",
  "callers": [
    {
      "name": "loginHandler",
      "file": "src/auth/login.ts",
      "line": 42,
      "depth": 1,
      "confidence": 1.0
    }
  ],
  "risk_level": "HIGH",
  "affected_processes": ["LoginFlow", "TokenRefresh"],
  "summary": {
    "d1_count": 2,
    "d2_count": 5,
    "d3_count": 12
  }
}

Step 3 — Present Results

Target: validateUser

Direction: upstream (what depends on this)

Risk Level: HIGH

---

Depth 1 — WILL BREAK (direct callers):

Symbol	File	Line
loginHandler	src/auth/login.ts	42
apiMiddleware	src/api/middleware.ts	15

Depth 2 — LIKELY AFFECTED:

Symbol	File
authRouter	src/routes/auth.ts
sessionManager	src/auth/session.ts

Depth 3 — MAY NEED TESTING:

12 transitive dependencies...

---

Affected Processes: LoginFlow, TokenRefresh

Step 4 — 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

HIGH or CRITICAL risk → warn user before proceeding with edits.

Step 5 — Recommendation

• LOW: Safe to edit, verify tests pass
• MEDIUM: Review d=1 items, update them, run integration tests
• HIGH: Draft plan, update all d=1 callers, full test suite
• CRITICAL: Flag to user — may need broader coordination

$ARGUMENTS