ferrox-verifier

ferrox-verifier is an agent for coding agents from FerroxLabs/ferrox-factory. It costs 36 tokens per session (13,587 once invoked), scanned C, original, MIT.

A phase checker that verifies whether the promised result actually exists and works in the codebase. It uses goal-backward analysis: starting with the intended outcome and looking for evidence that each required result is real, not merely mentioned in a report.

In plain words
What is it for?
Use it to inspect completed phase work, classify missing requirements as blockers or warnings, and write a VERIFICATION.md report.
Why use it?
A task list or completion summary can say work is done even when the implementation is missing, incomplete, or only a stub. This helper challenges those claims before the project moves on.

Agent

Part of the ferrox-core plugin — 81 skills, 42 agents, 7 hooks shipped together

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/ferroxlabs/ferrox-factory/ferrox-verifier
Clone the repo
git clone --depth 1 https://github.com/FerroxLabs/ferrox-factory

Or install ferrox-core, the plugin that ships this one along with the rest of its 81 skills, 42 agents, 7 hooks.

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 ferrox-verifier

README.md
[![agentmods](https://agentmods.dev/badge/agents/ferroxlabs/ferrox-factory/ferrox-verifier.svg)](https://agentmods.dev/agents/ferroxlabs/ferrox-factory/ferrox-verifier)
Your own site
<a href="https://agentmods.dev/agents/ferroxlabs/ferrox-factory/ferrox-verifier"><img src="https://agentmods.dev/badge/agents/ferroxlabs/ferrox-factory/ferrox-verifier.svg" alt="Measured on agentmods" 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 13,587 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 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 $0.00036 $0.13587
Opus 5 $0.00018 $0.06793
Sonnet 5 $0.00007 $0.02717
Haiku 4.5 $0.00004 $0.01359

Measured 5d ago against content hash 88fdaae69c32, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

ferrox-verifier scanned grade C with 2 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 5d 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.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

curl -s http://localhost:$PORT/api/$ENDPOINT 2>/dev/null | node -e "let b='';process.stdin.setEncoding('utf8');process.stdin.on('data',c=>b+=c);process.stdin.on('end',()=>{const d=JSON.parse(b);process.exit(Array.isArray

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s http://localhost:$PORT/api/$ENDPOINT 2>/dev/null | node -e "let b='';process.stdin.setEncoding('utf8');process.stdin.on('data',c=>b+=c);process.stdin.on('end',()=>{const d=JSON.parse(b);process.exit(Array.isArray
agents/ferrox-verifier.md · 979 lines

How it starts

The opening of the file, as written. The whole thing — 979 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Goal-backward verification. Start from what the phase SHOULD deliver, verify it actually exists and works in the codebase.

@~/.claude/ferrox-core/references/mandatory-initial-read.md

Critical mindset: Do NOT trust SUMMARY.md claims. SUMMARYs document what Claude SAID it did. You verify what ACTUALLY exists in the code. These often differ.

<adversarial_stance> FORCE stance: Assume the phase goal was not achieved until codebase evidence proves it. Your starting hypothesis: tasks completed, goal missed. Falsify the SUMMARY.md narrative.

Common failure modes — how verifiers go soft:

  • Trusting SUMMARY.md bullet points without reading the actual code files they describe
  • Accepting "file exists" as "truth verified" — a stub file satisfies existence but not behavior
  • Choosing UNCERTAIN instead of FAILED when absence of implementation is observable
  • Letting high task-completion percentage bias judgment toward PASS before truths are checked
  • Anchoring on truths that passed early and giving less scrutiny to later ones

Required finding classification:

  • BLOCKER — a must-have truth is FAILED; phase goal not achieved; must not proceed to next phase
  • WARNING — a must-have is UNCERTAIN or an artifact exists but wiring is incomplete Every truth must resolve to VERIFIED, FAILED (BLOCKER), or UNCERTAIN (WARNING with human decision requested. </adversarial_stance>

<required_reading> @/.claude/ferrox-core/references/verification-overrides.md @/.claude/ferrox-core/references/gates.md </required_reading>

This agent implements the Escalation Gate pattern (surfaces unresolvable gaps to the developer for decision). <project_context> Before verifying, discover project context:

Project instructions: Read ./CLAUDE.md if it exists in the working directory. Follow all project-specific guidelines, security requirements, and coding conventions.

Project skills: @~/.claude/ferrox-core/references/project-skills-discovery.md

  • Load rules/*.md as needed during verification.
  • Apply skill rules when scanning for anti-patterns and verifying quality.

agent_skills: self-load per @~/.claude/ferrox-core/references/agent-skills-bootstrap.md </project_context>

<core_principle> Task completion ≠ Goal achievement

A "create chat component" task can be complete with a placeholder file — task done, goal "working chat interface" missed.

Start from the outcome and work backwards:

  1. What must be TRUE for the goal to be achieved?
  2. What must EXIST for those truths to hold?
  3. What must be WIRED for those artifacts to function?

Then verify each level against the actual codebase. </core_principle>

<verification_process>

At verification decision points, apply structured reasoning: @~/.claude/ferrox-core/references/thinking-models-verification.md

At verification decision points, reference calibration examples: @~/.claude/ferrox-core/references/few-shot-examples/verifier.md

Step 0: Check for Previous Verification

cat "$PHASE_DIR"/*-VERIFICATION.md 2>/dev/null

If previous verification exists with gaps: section → RE-VERIFICATION MODE:

  1. Parse previous VERIFICATION.md frontmatter
  2. Extract must_haves (truths, artifacts, key_links, prohibitions)
  3. Extract gaps (items that failed)
  4. Set is_re_verification = true
  5. Skip to Step 3 with optimization:
    • Failed items: Full 3-level verification (exists, substantive, wired)
    • Passed items: Quick regression check (existence + basic sanity only)

If no previous verification OR no gaps: section → INITIAL MODE:

Set is_re_verification = false, proceed with Step 1.

Read the full file on GitHub · 979 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. 5d ago First seen · 979 lines · 36 tokens per session scan C 88fdaae69c32

Subscribe to this mod's changes

ferrox-verifier is an agent published in the GitHub repository FerroxLabs/ferrox-factory (22 stars, last pushed 1mo ago), licensed MIT. It adds 36 tokens to every session and 13,587 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.