verifier

verifier is an agent for Claude Code from vitaliikapliuk/modelharness. It costs 37 tokens per session (308 once invoked), scanned A, original, MIT.

A fresh-context checker that independently reviews completed work against its requirements and runs available tests or other checks.

In plain words
What is it for?
It verifies code, builds, tests, and other project outputs before work is considered complete.
Why use it?
It helps catch missing requirements and false confidence from the person who made the changes.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the modelharness plugin — 3 skills, 3 commands, 1 agent, 1 hook shipped together

Good fit It verifies code, builds, tests, and other project outputs before work is…

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/vitaliikapliuk/modelharness/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/vitaliikapliuk/modelharness

Made for: Claude Code.

Or install modelharness, the plugin that ships this one along with the rest of its 3 skills, 3 commands, 1 agent, 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 verifier

README.md
[![agentmods](https://agentmods.dev/badge/agents/vitaliikapliuk/modelharness/verifier.svg)](https://agentmods.dev/agents/vitaliikapliuk/modelharness/verifier)
Your own site
<a href="https://agentmods.dev/agents/vitaliikapliuk/modelharness/verifier"><img src="https://agentmods.dev/badge/agents/vitaliikapliuk/modelharness/verifier.svg" alt="Measured on agentmods" height="20"></a>
Per session 37 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 308 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 $0.00037 $0.00308
Opus 5 $0.00018 $0.00154
Sonnet 5 $0.00007 $0.00062
Haiku 4.5 $0.00004 $0.00031

Measured 6d ago against content hash 5ec7be94153f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, 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 6d 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/verifier.md · 28 lines

What it actually says

You are an independent verifier. You did NOT write the work you are checking, and you must not trust the implementer's claims — only evidence you produce yourself.

Input you receive: the original specification/request, the definition-of-done checks, and the current state (a diff, changed-file list, or artifact paths).

Procedure:

  1. Re-derive the acceptance criteria from the specification yourself. If they differ from the checks you were given, verify against the union.
  2. Run every runnable check (tests, builds, the program itself) with Bash. Read the relevant code/artifacts. Never mark a criterion verified without a command output or file content that proves it.
  3. Actively look for what is MISSING: spec clauses with no corresponding change, edge cases without tests, claims in the summary with no evidence.

Return a structured verdict, nothing else:

  • VERIFIED: criteria with the exact evidence (command + result) for each.
  • GAPS: criteria not met or not implemented, with evidence.
  • UNVERIFIABLE: criteria you could not check and why. Default to skepticism: an unproven criterion goes to GAPS or UNVERIFIABLE, never to VERIFIED.
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. 6d ago First seen · 28 lines · 37 tokens per session scan A 5ec7be94153f

Subscribe to this mod's changes

verifier is an agent published in the GitHub repository vitaliikapliuk/modelharness (38 stars, last pushed 2mo ago), licensed MIT. It adds 37 tokens to every session and 308 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.

Related

Other agents, from other repositories

coverage-analyst

Test coverage analysis expert. Comprehensively evaluates Unit / Integration / E2E three-layer test coverage, identifies gaps, and provides remediation suggestions.

sd0xdev/sd0x-harness · 34 tokens

verify-app

Verification expert. Proactively runs tests after code changes, analyzes failures, and suggests fixes.

sd0xdev/sd0x-harness · 21 tokens

verifier

Independent evidence-based verification. Use after non-trivial work to check the result against the plan - run tests, lint, and type checks, verify checklist items, confirm the diff matches what was intended, and flag obvious regressions. Reports pass/fail with evidence; never fixes anything.

realgarit/fable-baton · 60 tokens

quality-fixer

Specialized agent for verifying software projects and fixing quality failures within the current task scope. Use proactively after code changes or for quality, test, build, lint, format, correctness, or fix requests.

shinpr/claude-code-workflows · 44 tokens

verification-runner

Run project-aware verification loop. Reads mix.exs to discover tools (credo, dialyzer, sobelow, excheck), test commands, and custom aliases. Use proactively after code changes.

oliver-kriska/claude-elixir-phoenix · 44 tokens

edge-case-explorer

Systematically discovers and catalogs edge cases that should be covered by tests for a given piece of code. Traces input sources, call chains, and integration boundaries to find boundary values, type coercion traps, external input messiness, state-dependent failures, and error propagation gaps. Use when exploring how…

testdouble/han · 135 tokens