verify-changes

A verification workflow that runs changed code to check that it actually works. It matches the test to the kind of change, such as reproducing a bug or running a build.

In plain words
What is it for?
Use it after fixing bugs, adding features, refactoring, changing APIs, updating interfaces, editing configuration, or changing build and infrastructure code.
Why use it?
It replaces assumptions based on code inspection or type checks with evidence from execution. This helps catch changes that look correct but fail when used.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/vudovn/ag-kit/verify-changes
Any agent
npx skills add vudovn/ag-kit --skill verify-changes
Clone the repo
git clone --depth 1 https://github.com/vudovn/ag-kit

Made for: Claude Code, Codex.

Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 918 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00038 $0.00918
Opus 5 $0.00019 $0.00459
Sonnet 5 $0.00008 $0.00184
Haiku 4.5 $0.00004 $0.00092

Measured 2d ago against content hash a4ab56f9b3e8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

verify-changes scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl http://localhost:3000/api/endpoint
.agents/skills/verify-changes/SKILL.md · 129 lines

How it starts

The opening of the file, as written. The whole thing — 129 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Verify Changes — Prove Code Works

"Code that exists" ≠ "Code that works." This skill ensures changes are verified through execution.

Core Principle

❌ Verification by inspection:  "I can see the function exists, it should work"
❌ Verification by assumption:  "The types check out, so it's correct"
✅ Verification by execution:   "I ran it, here's the output, it works because [evidence]"

Verification Protocol

Step 1: Identify What Changed

- Which files were modified?
- What behavior should be different now?
- What was the original bug/requirement?

Step 2: Determine Verification Method

Change Type Verification Method
Bug fix Reproduce the original bug scenario → confirm it no longer occurs
New feature Run the feature → confirm expected output
Refactor Run existing tests → confirm nothing broke
API change Call the endpoint → confirm response shape
UI change Render the component → confirm visual output
Config change Load the config → confirm values applied
Build/infra Run build command → confirm success

Step 3: Execute Verification

# For Node.js projects
npm run build          # Does it compile?
npm run test           # Do tests pass?
npm run dev            # Does it start?

# For specific files
node -e "require('./path/to/module'); console.log('✅ Loads correctly')"

# For API endpoints
curl http://localhost:3000/api/endpoint

# For scripts
python script.py --test

Step 4: Report Evidence

## Verification Report

### What was changed
- [File list and summary]

### How it was verified
- [Exact commands run]

### Evidence
- Build: ✅ Compiled without errors
- Tests: ✅ 42/42 passing
- Runtime: ✅ Server starts, endpoint returns expected JSON
- Edge case: ✅ Empty input handled correctly

### Not yet verified
- [Anything that couldn't be tested automatically]

Verification Checklist by Project Type

Web Application

  • npm run build — compiles without errors
  • npm run lint — no linting errors
  • npm run test — all tests pass
  • Dev server starts successfully
  • Changed pages render correctly
  • No console errors in browser

Read the full file on GitHub · 129 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 129 lines · 38 tokens per session scan A a4ab56f9b3e8

Subscribe to this mod's changes

verify-changes is a skill published in the GitHub repository vudovn/ag-kit (8,162 stars, last pushed 2d ago), licensed MIT. It adds 38 tokens to every session and 918 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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