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Interpreting vg impact Output

Learn how to read vg impact results — the reverse-reachability blast radius and decay confidence — so you can tell a contained change from a risky one and act accordingly.

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vg impact gives you a blast radius, but the value is in reading it correctly. This article explains what the output means and how to translate it into decisions.

What the output represents

vg impact computes the blast radius of changing a node using reverse reachability: it walks backward through the call graph from your target to find everything that could be affected. The result is the set of dependent nodes, weighted by decay confidence — closer dependents carry more confidence than distant ones.

Because the computation is structural and deterministic, the output is repeatable: the same code and node always yield the same radius.

Reading the radius

  • Size: how many nodes are reachable backward. A small set means the change is contained; a large set means it is far-reaching.
  • Distance: how directly each dependent connects. Direct callers are the most likely to be affected; distant ones less so.
  • Confidence: the decay weighting tells you where to focus. High-confidence, nearby dependents deserve attention first.

Turning output into action

  1. Small radius, high confidence: proceed; verify the direct dependents and ship.
  2. Large radius: consider splitting the change, adding tests, or staging the rollout.
  3. Surprising dependents: if a node appears that you did not expect, trace the connection with vg path to understand why.

Pair it with tests

The output becomes a concrete checklist when you add the tests flag — it surfaces exactly the tests that exercise the affected code:

vg impact --tests

Keep it accurate

Impact only reflects the graph at build time. If the code changed, rebuild before trusting the radius:

vg build
vg impact

Common misreadings

  • Treating a large radius as a blocker rather than a planning signal.
  • Ignoring confidence and treating every distant dependent as equally likely to break.
  • Running impact on a stale graph and acting on outdated dependents.

Related

See the articles on impact analysis before a change, test impact with --tests, and finding a dependency path with vg path.

Vibgrate CLI

See a real scan run

A replay of the actual CLI running against our test repositories — live progress, real findings, a genuine DriftScore. Nothing executes in your browser.

Replay
demo@vibgrate — bash
npx @vibgrate/cli scan
 
╭──────────────────────────────────────────╮
Vibgrate Drift Report
╰──────────────────────────────────────────╯
 
── node-turborepo (node) .
Runtime: >=18.0.0 (6 majors behind)
Frameworks:
Turbo: 1.13.4 → 2.10.12 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
1 current 1 1-behind 3 2+ behind 1 unknown
 
── @repo/admin (node) apps/admin
Frameworks:
TanStack Query: 5.102.5 → 5.102.5 (current)
React: 18.3.1 → 19.2.8 (1 behind)
React DOM: 18.3.1 → 19.2.8 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Vite: 5.4.21 → 8.2.2 (3 behind)
Dependencies:
3 current 9 1-behind 3 2+ behind 4 unknown
 
── @repo/api (node) apps/api
Frameworks:
Express: 4.22.2 → 5.2.1 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Vitest: 1.6.1 → 4.1.11 (3 behind)
Dependencies:
7 current 5 1-behind 3 2+ behind 4 unknown
 
── @repo/web (node) apps/web
Frameworks:
Next.js: 14.2.35 → 16.3.3 (2 behind)
React: 18.3.1 → 19.2.8 (1 behind)
React DOM: 18.3.1 → 19.2.8 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
2 current 6 1-behind 3 2+ behind 5 unknown
 
── @repo/config (node) packages/config
Frameworks:
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
2 current 2 1-behind 5 2+ behind 0 unknown
 
── @repo/database (node) packages/database
Frameworks:
Prisma: 5.22.0 → 7.10.0 (2 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
1 current 0 1-behind 3 2+ behind 1 unknown
 
── @repo/types (node) packages/types
Frameworks:
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Dependencies:
0 current 0 1-behind 1 2+ behind 1 unknown
 
── @repo/ui (node) packages/ui
Frameworks:
React: 18.3.1 → 19.2.8 (1 behind)
TypeScript: 5.9.3 → 7.0.2 (2 behind)
React: 18.3.1 → 19.2.8 (1 behind)
Dependencies:
1 current 4 1-behind 1 2+ behind 1 unknown
 
── @repo/utils (node) packages/utils
Frameworks:
TypeScript: 5.9.3 → 7.0.2 (2 behind)
Vitest: 1.6.1 → 4.1.11 (3 behind)
Dependencies:
0 current 1 1-behind 2 2+ behind 1 unknown
 
Tech Stack
Frontend: React, React DOM
Meta-frameworks: Next.js
Bundlers: tsx, Turbo, Vite
CSS / UI: Autoprefixer, PostCSS, Tailwind CSS
Backend: Express
ORM / Database: Prisma, Prisma Client
Testing: Vitest
Lint & Format: ESLint, ESLint Prettier, ESLint React, Prettier, typescript-eslint
 
Services & Integrations
Auth: JWT 9.0.3
Databases: Prisma 5.22.0
 
TypeScript
v5.3.3 · strict ✔ · MIXED · target: ES2022
 
Build & Deploy
Package Managers: pnpm
Monorepo: npm-workspaces, pnpm-workspaces, turbo
 
Product Purpose Signals
Frameworks: react, nextjs
Evidence: 177
Top Signals:
- [heading] Dashboard (apps/admin/src/pages/Dashboard.tsx)
- [title] Revenue Overview (apps/admin/src/pages/Dashboard.tsx)
- [copy] workspace:* (packages/ui/package.json)
- [copy] ./dist (packages/ui/tsconfig.json)
- [copy] ./src/index.ts (packages/ui/package.json)
- [copy] @repo/config/tsconfig-base.json (packages/ui/tsconfig.json)
- [copy] @repo/ui (packages/ui/package.json)
- [copy] #3b82f6 (apps/admin/src/pages/Dashboard.tsx)
Unknowns:
- No pricing or billing evidence found.
- No integrations/connectors evidence found.
- No route structure evidence found.
 
Security Posture
Lockfile ✖ · .env ✔ · node_modules ✔
 
Platform
Native modules: turbo
 
Code Quality
Files: 36 · Functions: 183 · Avg complexity: 2.62 · Avg length: 21.13 lines
Max nesting: 2 · Circular deps: 0 · Dead code: 0%
God files: apps/admin/src/pages/Products (448 lines)
 
Database Schema
postgresql · 8 models · 1 enum
Models: Address, CartItem, Category, Order, OrderItem (+3 more)
 
Findings (16 errors, 11 warnings)
Node.js runtime ">=18.0.0" reached end-of-life on 2025-04-30 (latest: 24.0.0).
vibgrate/runtime-eol in .
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in .
60% of dependencies are 2+ major versions behind in node-turborepo.
vibgrate/dependency-rot in .
@types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).
vibgrate/dependency-major-lag in .
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in apps/admin
Vite is 3 major versions behind (current: 5.4.21, latest: 8.2.2).
vibgrate/framework-major-lag in apps/admin
vite is 3 major versions behind (spec: ^5.0.12, latest: 8.2.2).
vibgrate/dependency-major-lag in apps/admin
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in apps/api
Vitest is 3 major versions behind (current: 1.6.1, latest: 4.1.11).
vibgrate/framework-major-lag in apps/api
@types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).
vibgrate/dependency-major-lag in apps/api
vitest is 3 major versions behind (spec: ^1.2.1, latest: 4.1.11).
vibgrate/dependency-major-lag in apps/api
Next.js is 2 major versions behind (current: 14.2.35, latest: 16.3.3).
vibgrate/framework-major-lag in apps/web
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in apps/web
@types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).
vibgrate/dependency-major-lag in apps/web
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/config
56% of dependencies are 2+ major versions behind in @repo/config.
vibgrate/dependency-rot in packages/config
eslint-plugin-react-hooks is 3 major versions behind (spec: ^4.6.0, latest: 7.1.1).
vibgrate/dependency-major-lag in packages/config
Prisma is 2 major versions behind (current: 5.22.0, latest: 7.10.0).
vibgrate/framework-major-lag in packages/database
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/database
75% of dependencies are 2+ major versions behind in @repo/database.
vibgrate/dependency-rot in packages/database
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/types
100% of dependencies are 2+ major versions behind in @repo/types.
vibgrate/dependency-rot in packages/types
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/ui
TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).
vibgrate/framework-major-lag in packages/utils
Vitest is 3 major versions behind (current: 1.6.1, latest: 4.1.11).
vibgrate/framework-major-lag in packages/utils
67% of dependencies are 2+ major versions behind in @repo/utils.
vibgrate/dependency-rot in packages/utils
vitest is 3 major versions behind (spec: ^1.2.1, latest: 4.1.11).
vibgrate/dependency-major-lag in packages/utils
 
╭──────────────────────────────────────────╮
Top Priority Actions
╰──────────────────────────────────────────╯
 
1. Upgrade EOL runtime in node-turborepo
End-of-life runtimes no longer receive security patches and block ecosystem upgrades.
./.
>=18.0.0 → 24.0.0 (6 majors behind)
Impact: −10 drift points (runtime & EOL)
 
2. Fix security posture: no lockfile found
Without a lockfile, installs are non-deterministic. Run the install command to generate one and commit it.
./
Missing: package-lock.json, pnpm-lock.yaml, or yarn.lock
 
3. Upgrade Vite 5.4.21 → 8.2.2 in @repo/admin (+2 more)
3 major versions behind. Major framework drift increases breaking change risk and blocks access to security fixes and performance improvements.
./apps/admin
Vite: 5.4.21 → 8.2.2 (3 majors behind)
./apps/api
Vitest: 1.6.1 → 4.1.11 (3 majors behind)
./packages/utils
Vitest: 1.6.1 → 4.1.11 (3 majors behind)
Impact: −5–15 drift points
 
4. Reduce dependency rot in @repo/types (100% severely outdated)
1 of 1 dependencies are 2+ majors behind. Run `npm outdated` and prioritise packages with known CVEs or breaking API changes.
./packages/types
typescript: 5.9.3 → 7.0.2 (2 majors behind)
Impact: −5–10 drift points
 
5. Reduce dependency rot in @repo/database (75% severely outdated)
3 of 4 dependencies are 2+ majors behind. Run `npm outdated` and prioritise packages with known CVEs or breaking API changes.
./packages/database
@prisma/client: 5.22.0 → 7.10.0 (2 majors behind)
prisma: 5.22.0 → 7.10.0 (2 majors behind)
typescript: 5.9.3 → 7.0.2 (2 majors behind)
Impact: −5–10 drift points
 
╭──────────────────────────────────────────╮
Architecture Layers
╰──────────────────────────────────────────╯
 
Archetype: nextjs (80% confidence)
Files classified: 24 (11 unclassified)
Folders classified: 8
apps/admin/src presentation 100% 4 files
apps/admin/src/pages presentation 100% 2 files
apps/api/src/middleware middleware 100% 2 files
apps/api/src/routes routing 100% 2 files
apps/web/src/app presentation 100% 4 files
apps/web/src/app/products presentation 100% 2 files
apps/web/src/app/products/[id] presentation 100% 1 file
packages/ui/src presentation 100% 6 files
Unclassified source (sample): 11
 
presentation 15 files drift ████████████████████ 100 risk high
routing 4 files drift ████████████████████ 100 risk high
middleware 2 files drift ███████▍░░░░░░░░░░░░ 37 risk moderate
config 2 files drift ░░░░░░░░░░░░░░░░░░░░ 0 risk none
shared 1 file drift ████████████████████ 100 risk high
 
╭──────────────────────────────────────────╮
DriftScore Summary
╰──────────────────────────────────────────╯
 
DriftScore: 66/100
Risk Level: HIGH
Projects: 9
Classified: 8 nano · 1 micro · 0 small · 0 standard
Billable: 0.42 · 9 detected → 0.42 billable projects (micro-project pricing)
0.1 micro · 0.32 nano
These fractions add up across repositories, then round down to whole billable projects.
 
Score Breakdown
Runtime: ████████████████████ 100
Frameworks: █████████▏░░░░░░░░░░ 46
Dependencies: ██████▏░░░░░░░░░░░░░ 31
EOL Risk: ████████████████████ 100
 
Scanned at 2026-08-26T09:08:28.481Z · 7.1s · 286 files scanned · 56 workspace files · 27 dirs
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