verifier

verifier is a skill for Claude Code from taniwhaai/arai. It costs 122 tokens per session (3,428 once invoked), scanned A, original, Apache-2.0.

An independent checker for software work against a contract's acceptance criteria. Acceptance criteria are the specific conditions an implementation must meet.

In plain words
What is it for?
Reading contracts, writing separate tests, running them against existing implementations, and reporting which requirements pass or fail.
Why use it?
It reduces the risk that the person who wrote the code also defines and tests its interpretation of the requirements, leaving shared mistakes unnoticed.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: mentions subagents.

Good fit Reading contracts, writing separate tests, running them against existing implementations, and reporting which requirements pass or fail.

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Install with agentmods
npx agentmods add skills/taniwhaai/arai/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.

Any agent
npx skills add taniwhaai/arai --skill verifier
Clone the repo
git clone --depth 1 https://github.com/taniwhaai/arai

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 verifier

README.md
[![agentmods](https://agentmods.dev/badge/skills/taniwhaai/arai/verifier.svg)](https://agentmods.dev/skills/taniwhaai/arai/verifier)
Your own site
<a href="https://agentmods.dev/skills/taniwhaai/arai/verifier"><img src="https://agentmods.dev/badge/skills/taniwhaai/arai/verifier.svg" alt="Measured on agentmods" height="20"></a>
Per session 122 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,428 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 $0.00122 $0.03428
Opus 5 $0.00061 $0.01714
Sonnet 5 $0.00024 $0.00686
Haiku 4.5 $0.00012 $0.00343

Measured 8d ago against content hash e9589c7c077f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

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.

.claude/skills/verifier/SKILL.md · 173 lines

How it starts

The opening of the file, as written. The whole thing — 173 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Verifier

Verify that an implementation or composition satisfies its contract's acceptance criteria. You did not write this code. Your job is to read the contract independently, write your own tests against the acceptance criteria, run them against the implementation, and report what passed and what failed.

Why this skill exists

The implementor wrote the code and wrote tests for it. Both came from the same context, with the same assumptions, and the same potential blind spots. If the implementor misread the contract, the implementor's tests will misread it the same way, and they will pass. "Tests pass" therefore is not "contract satisfied" — it's "implementor's interpretation of the contract is internally consistent".

Verification breaks that loop by introducing a second interpreter. You read the contract from scratch. You write tests against acceptance criteria as you understand them, not as the implementor did. You run those tests against the existing source code. If your independent reading and the implementor's converge on the same behaviour, the contract is genuinely satisfied. If they diverge, that's a finding — possibly a bug in the implementation, possibly an ambiguity in the contract, possibly a misreading on either side.

This is also why the verifier role is mandatory and not optional. An orchestrator that asks the user to "skip verification" is removing the only structural check on contract satisfaction. The skip path doesn't exist; the only options are verify-now or verify-later (deferred verification with a clearly recorded debt).

What you have

You have been given exactly four things:

  1. The contract — the manifest the implementation claims to satisfy. This includes the acceptance criteria, which are the load-bearing part for your work.
  2. The shared vocabulary — data shapes and external systems the contract refers to.
  3. The project context — language, toolchain commands (test/build/format/lint), code style. Use project_context.toolchain.commands.test to run tests; never invent or re-derive language-specific test commands.
  4. The implementation manifest — gives you the source_paths of the files to verify, plus any notes the implementor left.

Read the full file on GitHub · 173 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 173 lines · 122 tokens per session scan A e9589c7c077f

Subscribe to this mod's changes

verifier is a skill published in the GitHub repository taniwhaai/arai (7 stars, last pushed 25d ago), licensed Apache-2.0. It adds 122 tokens to every session and 3,428 once invoked, about $0.0006 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.