attestation-verifier

attestation-verifier is an agent for Claude Code from masanami/claude-harness. It costs 64 tokens per session (1,683 once invoked), scanned A, original, no licence file.

A skeptical verification agent for claims about dependencies shared across code repositories. It independently retrieves the dependency's source code and tries to disprove the stated assumptions and evidence.

In plain words
What is it for?
Use it to verify assumptions, supporting evidence, and claimed behavior in code that another repository depends on.
Why use it?
It reduces the risk of accepting a cross-repository dependency conclusion without checking the actual implementation.

Agent for Claude Code

Written for Claude Code: effort in frontmatter. Also seen: model in frontmatter.

Part of the claude-harness plugin — 23 skills, 22 agents, 1 hook shipped together

Good fit Use it to verify assumptions, supporting evidence, and claimed behavior in code that another repository depends on.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/masanami/claude-harness/attestation-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/masanami/claude-harness

Made for: Claude Code.

Or install claude-harness, the plugin that ships this one along with the rest of its 23 skills, 22 agents, 1 hook.

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 attestation-verifier

README.md
[![agentmods](https://agentmods.dev/badge/agents/masanami/claude-harness/attestation-verifier/github.svg)](https://agentmods.dev/agents/masanami/claude-harness/attestation-verifier)
Your own site
<a href="https://agentmods.dev/agents/masanami/claude-harness/attestation-verifier"><img src="https://agentmods.dev/badge/agents/masanami/claude-harness/attestation-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 attestation-verifier

Your own site · 80×15
<a href="https://agentmods.dev/agents/masanami/claude-harness/attestation-verifier"><img src="https://agentmods.dev/badge/agents/masanami/claude-harness/attestation-verifier.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 64 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,683 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 unknown 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 $0.00064 $0.01683
Opus 5 $0.00032 $0.00842
Sonnet 5 $0.00013 $0.00337
Haiku 4.5 $0.00006 $0.00168

Measured 9d ago against content hash fbc9574ace52, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

attestation-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 9d 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/attestation-verifier.md · 74 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 9d ago First seen · 74 lines · 64 tokens per session scan A fbc9574ace52

Subscribe to this mod's changes

attestation-verifier is an agent published in the GitHub repository masanami/claude-harness (5 stars, last pushed 2d ago), with no licence file. It adds 64 tokens to every session and 1,683 once invoked, about $0.0003 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 2026-08-31.

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