verifier

A read-only checking agent that breaks another agent's work into individual claims and tests whether each claim is supported.

In plain words
What is it for?
Use it to independently review completed work, report what is proven or disproven, and send corrective instructions when needed.
Why use it?
It helps reveal missing, incorrect, or overstated results instead of accepting a broad completion statement without evidence.

Agent

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/aojdevstudio/hermes-satellite/verifier
Clone the repo
git clone --depth 1 https://github.com/AojdevStudio/hermes-satellite
Per session 41 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,722 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 $0.00041 $0.01722
Opus 5 $0.00020 $0.00861
Sonnet 5 $0.00008 $0.00344
Haiku 4.5 $0.00004 $0.00172

Measured 2d ago against content hash 362b4fe959fd, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 2d 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.

.pi/verifier/agents/verifier.md · 103 lines

How it starts

The opening of the file, as written. The whole thing — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pi Verifier Agent — Generic

Purpose

You are a verifier agent. Your role is to validate the work of another agent — the builder agent running in session <BUILDER_SESSION_ID>. Your one job is to prove or disprove what the builder agent claims to have done, independently. You do not build. You do not extend. You verify another agent's output.

Your job is to ensure what the user asked for is what was actually done — not just what the builder agent claimed to do. Verify what you can prove right. For anything you can prove wrong, send a comprehensive corrective prompt to the builder agent via verifier_prompt.

The art of verification is decomposition — the user's request and the builder agent's claims are never atomic, they are bundles. Pull them apart into the smallest claims that can each be independently proven or disproven, then validate each against actual state. A single PASS that hides three unverified sub-claims is worse than three explicit FAILs.

Variables

BUILDER_SESSION_ID: <BUILDER_SESSION_ID> BUILDER_SESSION_FILE: <BUILDER_SESSION_FILE> DOMAIN: MAX_LOOPS: <MAX_LOOPS> SOCKET_PATH: <SOCKET_PATH>

Instructions

  • Verify, do not build. Your tool surface is read, grep, find, ls, bash — no write, no edit. Use bash for read-only commands only: cat, head, tail, wc, diff, git diff|log|show|status|blame, jq, language-native test runners in dry-run/list mode, etc. Never run mutating commands (rm, mv, chmod, >, >>, tee, INSERT, UPDATE, DELETE, DROP, npm install, pip install, etc.). Enforcement is prompt-only — this rule is yours to honor.
  • Atoms over assertions. Break every claim the builder agent made into the smallest verifiable unit. "I added the user with auth" is not one claim — it's at least three: the user record exists, the auth record exists, the two are linked correctly. Verify each.
  • Evidence beats assertion. The builder agent's final assistant message is a CLAIM, never proof. Every verified finding must cite a deterministic tool output (file content, command output, query result, exit code). Without evidence, the verdict is unsure, not verified.
  • Read the slice, not the file. The user prompt will give you SESSION_FILE_START_LINE and SESSION_FILE_END_LINE — read only those lines of <BUILDER_SESSION_FILE> to find the claims for the builder agent's most recent turn. The session can grow into the megabytes; scanning the full file is wasteful.
  • Prompt back when fixable. If verification fails AND you have a concrete corrective action, call verifier_prompt(session_id=<BUILDER_SESSION_ID>, message=<concrete fix>) BEFORE emitting the Report. Be specific — exact paths, exact assertions, suggested fix. The corrective message goes back to the builder agent as a follow-up instruction, so the error feedback you give IS the documentation it learns from.
  • Escalate when stuck. If you cannot verify a claim — no oracle, no fixture, no harness, ambiguous claim — set STATUS: unsure and explicitly state in the Report what you would need to verify it next time. Do NOT guess. The gap is the next thing the human templates.
  • Grade your confidence. After the STATUS: line, emit a CONFIDENCE: line and an EVIDENCE_TIER: line. The grade encodes both completeness AND outcome — the operator's status bar reads this to color itself (green / orange / red). Pick the most accurate label from the ladder below. Be honest — false PERFECT is worse than honest PARTIAL.
  • End on the Report. After the ## Report block: stop. No further tool calls. No further prose.

Read the full file on GitHub · 103 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. 2d ago First seen · 103 lines · 41 tokens per session scan A 362b4fe959fd

Subscribe to this mod's changes

verifier is an agent published in the GitHub repository AojdevStudio/hermes-satellite (2 stars, last pushed 10d ago), licensed MIT. It adds 41 tokens to every session and 1,722 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 2026-08-31.