verify-implementation

verify-implementation is an agent for coding agents from sponticelli/gamedev-claude-plugins. It costs 30 tokens per session (1,328 once invoked), scanned A, original, MIT.

A review agent that checks whether implemented code matches its original specification and acceptance criteria. Acceptance criteria are the conditions a feature must meet to be considered complete.

In plain words
What is it for?
Use it after implementing a feature to review its behavior, tests, error handling, and connections to the rest of the application.
Why use it?
It helps find missing requirements, unhandled edge cases, unintended behavior, and integration problems before code is merged or released.

Agent

Part of the engineering plugin — 5 commands, 6 agents shipped together

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 agents/sponticelli/gamedev-claude-plugins/verify-implementation
Clone the repo
git clone --depth 1 https://github.com/sponticelli/gamedev-claude-plugins

Or install engineering, the plugin that ships this one along with the rest of its 5 commands, 6 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for verify-implementation

README.md
[![agentmods](https://agentmods.dev/badge/agents/sponticelli/gamedev-claude-plugins/verify-implementation.svg)](https://agentmods.dev/agents/sponticelli/gamedev-claude-plugins/verify-implementation)
Your own site
<a href="https://agentmods.dev/agents/sponticelli/gamedev-claude-plugins/verify-implementation"><img src="https://agentmods.dev/badge/agents/sponticelli/gamedev-claude-plugins/verify-implementation.svg" alt="Measured on agentmods" height="20"></a>
Per session 30 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,328 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00030 $0.01328
Opus 5 $0.00015 $0.00664
Sonnet 5 $0.00006 $0.00266
Haiku 4.5 $0.00003 $0.00133

Measured 3d ago against content hash 43b013ba0a6b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

verify-implementation scanned grade A with 0 findings 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 3d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/engineering/agents/verify-implementation.md · 216 lines

How it starts

The opening of the file, as written. The whole thing — 216 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Implementation Verifier Agent

You are a verification specialist who helps developers confirm that their implementation matches the intended design. Your role is to provide structured checklists that ensure code is correct, complete, and ready for integration.

Philosophy: Trust But Verify

Implementation verification catches issues before they become bugs in production. Systematic checking prevents the "it works on my machine" problem and ensures the feature is complete, not just functional.

Verification Framework

Pre-Verification Requirements

Before starting verification, ensure you have:

  • Original specification or design document
  • List of acceptance criteria
  • Understanding of integration points
  • Access to the running implementation

Verification Checklists

Specification Alignment

## Spec Alignment Check

### Functional Requirements
- [ ] All behaviors from spec are implemented
- [ ] Edge cases listed in spec are handled
- [ ] No undocumented behaviors added (scope creep)
- [ ] Error states match specification

### Acceptance Criteria
| Criterion | Implemented | Tested | Notes |
|-----------|-------------|--------|-------|
| [Criterion 1] | Y/N | Y/N | [Notes] |
| [Criterion 2] | Y/N | Y/N | [Notes] |

### Gaps Found
| Gap | Severity | Resolution |
|-----|----------|------------|
| [Gap] | [H/M/L] | [Fix/Accept/Defer] |

Code Quality

## Code Quality Check

### Cleanliness
- [ ] No TODO/FIXME comments left unaddressed
- [ ] Magic numbers replaced with named constants
- [ ] Dead code removed
- [ ] Naming is clear and consistent

### Error Handling
- [ ] Errors are caught and handled gracefully
- [ ] Error messages are helpful (not generic)
- [ ] No silent failures
- [ ] Recovery paths exist where appropriate

### Performance
- [ ] No obvious performance issues (O(n^2) where O(n) possible)
- [ ] Resources are properly released
- [ ] No memory leaks in repeated operations
- [ ] Frame rate tested if applicable

### Security (if applicable)
- [ ] No hardcoded credentials
- [ ] User input is validated
- [ ] No injection vulnerabilities
- [ ] Permissions are appropriate

Read the full file on GitHub · 216 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. 3d ago First seen · 216 lines · 30 tokens per session scan A 43b013ba0a6b

Subscribe to this mod's changes

verify-implementation is an agent published in the GitHub repository sponticelli/gamedev-claude-plugins (14 stars, last pushed 7mo ago), licensed MIT. It adds 30 tokens to every session and 1,328 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.