fable-judge

fable-judge is a skill for Claude Code, Codex from ardhaecosystem/fable-method. It costs 69 tokens per session (3,331 once invoked), scanned A, original, MIT.

An adversarial checker for verifying claims that work is finished. It independently reruns stated checks, examines the actual changes, and looks for common ways a completion report could be wrong.

In plain words
What is it for?
It is for reviewing a completion report, past session, or skill/model test suite. It can rerun claimed verification, inspect differences, and test for failures.
Why use it?
It prevents a completion claim from being accepted without evidence. It reports defects or unverifiable checks without changing the work it is judging.

Skill for Claude CodeCodex

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 skills/ardhaecosystem/fable-method/fable-judge
Any agent
npx skills add ardhaecosystem/fable-method --skill fable-judge
Clone the repo
git clone --depth 1 https://github.com/ardhaecosystem/fable-method

Made for: Claude Code, Codex.

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 fable-judge

README.md
[![agentmods](https://agentmods.dev/badge/skills/ardhaecosystem/fable-method/fable-judge.svg)](https://agentmods.dev/skills/ardhaecosystem/fable-method/fable-judge)
Your own site
<a href="https://agentmods.dev/skills/ardhaecosystem/fable-method/fable-judge"><img src="https://agentmods.dev/badge/skills/ardhaecosystem/fable-method/fable-judge.svg" alt="Measured on agentmods" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,331 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 $0.00069 $0.03331
Opus 5 $0.00034 $0.01665
Sonnet 5 $0.00014 $0.00666
Haiku 4.5 $0.00007 $0.00333

Measured 4d ago against content hash c3f0e698d795, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fable-judge 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 4d 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.

skills/software-development/fable-judge/SKILL.md · 178 lines

How it starts

The opening of the file, as written. The whole thing — 178 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fable Judge

An adversarial verification gate. A "done" report is not a fact; it is a set of claims. The judge believes nothing it did not observe with its own tool calls. It re-runs every claimed verification, diffs the actual changes, hunts the classic frauds, and delivers a verdict backed by evidence. Judging changes nothing - this is a gate, not a reimplementation. If something is not runnable, the judge says so rather than rubber-stamping it.

Usage

/fable-judge <report|session> verify the finished work described in a report or past session
/fable-judge suite <target> run the trap suite against a skill or model via delegate_task

<report> is either a pasted completion report, a file path to one, or a session link the parent agent supplies. If no report is given, treat the most recent completed work in this conversation as the target.

Standing rules

  • Judging changes nothing. Never edit, fix, or "help" during a verdict run. If you find a defect, report it; do not repair it. Repairing during a verdict destroys the independence that makes the verdict worth anything. The sole exception is suite mode's delegate traps, which are designed to fail and are cleaned up by the trap framework, not by you.
  • Diff is ground truth; the report is not. What the report says was done is a claim. What git diff or a directory diff shows was done is the fact. Reconcile the two. Any change in the diff not mentioned in the report is a finding; any claim in the report absent from the diff is a finding.
  • Run, don't read. Reading code and nodding is not verification. Execute the tests, the build, the script, the command the report says it ran. If you cannot run it, say "not runnable here" and downgrade the verdict - never pass it on faith.
  • This is a gate, not a reimplementation. You verify what exists. You do not finish unfinished work, add missing tests, or improve the code. If the work is incomplete, the verdict is REFUTED or VERIFIED WITH CAVEATS, and the report says what is missing - that is the deliverable.
  • Believe nothing you did not observe. Every claim in the verdict traces to a tool call you made this run. No inherited trust from the parent agent, the report author, or a prior session's green checkmark.

Read the full file on GitHub · 178 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. 4d ago First seen · 178 lines · 69 tokens per session scan A c3f0e698d795

Subscribe to this mod's changes

fable-judge is a skill published in the GitHub repository ardhaecosystem/fable-method (12 stars, last pushed 1mo ago), licensed MIT. It adds 69 tokens to every session and 3,331 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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