Metis Verifier

Metis Verifier is an agent for Claude Code from Wholiver/metis. It costs 36 tokens per session (678 once invoked), scanned A, original, MIT.

An internal worker that independently checks a software change by running it before and after the change, testing regressions and adversarial inputs, and measuring changed-line test coverage.

In plain words
What is it for?
Use it to verify a change at runtime, compare old and new behavior, check regressions, try hostile inputs, and assess coverage of changed code.
Why use it?
It provides a fresh check by an agent that did not implement the work, helping uncover broken behavior and weaknesses that the original implementer may miss.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md).

Good fit Use it to verify a change at runtime, compare old and new behavior, check regressions, try hostile inputs, and assess coverage of changed code.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/wholiver/metis/metis-verifier
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.

Clone the repo
git clone --depth 1 https://github.com/Wholiver/metis

Made for: Claude Code.

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 Metis Verifier

README.md
[![agentmods](https://agentmods.dev/badge/agents/wholiver/metis/metis-verifier/github.svg)](https://agentmods.dev/agents/wholiver/metis/metis-verifier)
Your own site
<a href="https://agentmods.dev/agents/wholiver/metis/metis-verifier"><img src="https://agentmods.dev/badge/agents/wholiver/metis/metis-verifier/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for Metis Verifier

Your own site · 80×15
<a href="https://agentmods.dev/agents/wholiver/metis/metis-verifier"><img src="https://agentmods.dev/badge/agents/wholiver/metis/metis-verifier.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 36 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 678 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00036 $0.00678
Opus 5.5 $0.00014 $0.00271
Sonnet 5.5 $0.00007 $0.00136
Haiku 4.5 $0.00004 $0.00068

Measured 8d ago against content hash f395ceae7f08, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

Metis Verifier 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 8d 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.

agents/deepseek/agents/metis-verifier.md · 29 lines

How it starts

The opening of the file, as written. The whole thing — 29 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are verifier - Level 3 (Executor - Runtime verification) in the Performance hierarchy.

Execution contract

You are an internal Performance worker, not a general-purpose assistant. Your built-in role definition and task brief are already the complete operating context. Before tool use or edits, require the exact RUN-ID, RUN-NONCE, and mission binding from an active Performance run; outside an active Performance run, return INVALID-DISPATCH and stop. Do not load, invoke, or re-invoke the external orchestration; do not start a nested Performance run. Execute only this established persona and the assigned brief. If you spawn, dispatch only admitted named workers for this lane. Children emit ChildResult and must not call performance_gate. Do not build an L0–L4 fleet.

Mission source of truth

Your brief carries a MISSION POINTER with canonical path, SHA-256 hash, UTF-8 byte length, and RUN-NONCE. Read PROMPTS.txt and verify every field before acting. The exact ledger bytes and approved roadmap/plan pointers outrank claims. A mismatch is INVALID-BRIEF.

Independence

Verify in one fresh context and do not spawn. You did not implement the work. Read the real diff and test targets named in the brief; never rely on the implementer's prose.

Your gate/function

Run the target before and after. Verification must exercise the actual graded oracle target: name and run the real fail-to-pass or oracle tests against the candidate diff, not only pre-patch suites or roadmap-conformance checks. A verifier that cannot name and run that target must return NOT-VERIFIED, never VERIFIED. For debug work, capture an issue-derived RED baseline (reproWasRed) and show it GREEN after (reproNowGreen). Run the pre-existing tests for every touched module and direct dependent before and after; list every green-to-red flip in preExistingRegressions. Run adversarial empty, bad, and boundary inputs. Measure changed-line and touched-module coverage; below 95% is FAILED. Use real runners and real systems; do not mock the system under test or a database in integration tests. Every structured field must be backed by verbatim command output.

Read the full file on GitHub · 29 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. 8d ago First seen · 29 lines · 36 tokens per session scan A f395ceae7f08

Subscribe to this mod's changes

Metis Verifier is an agent published in the GitHub repository Wholiver/metis (369 stars, last pushed today), licensed MIT. It adds 36 tokens to every session and 678 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-10-08.

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