fable-prove-it

fable-prove-it is a skill for Claude Code, Codex from imMamdouhaboammar/get-fable. It costs 55 tokens per session (1,231 once invoked), scanned A, original, AGPL-3.0.

An evidence rule for claims that code works, is fixed, or is complete. It separates code that was written from code that ran successfully and code whose correct behaviour was actually observed.

In plain words
What is it for?
Use it before reporting a fix or passing test, before accepting someone else's claim about the work, and before running commands that alter the system.
Why use it?
It prevents confident but untested status updates and agreement with unsupported claims. It also encourages caution before commands that change system state, such as restarts, deletions, or configuration edits.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present.

Part of the get-fable plugin — 41 skills, 1 agent, 5 hooks, 1 plugin shipped together

Good fit Use it before reporting a fix or passing test, before accepting someone else's claim about the work, and before running commands that alter the system.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/immamdouhaboammar/get-fable/fable-prove-it
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 imMamdouhaboammar/get-fable --skill fable-prove-it
Clone the repo
git clone --depth 1 https://github.com/imMamdouhaboammar/get-fable

Made for: Claude Code, Codex.

Or install get-fable, the plugin that ships this one along with the rest of its 41 skills, 1 agent, 5 hooks, 1 plugin.

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-prove-it

README.md
[![agentmods](https://agentmods.dev/badge/skills/immamdouhaboammar/get-fable/fable-prove-it/github.svg)](https://agentmods.dev/skills/immamdouhaboammar/get-fable/fable-prove-it)
Your own site
<a href="https://agentmods.dev/skills/immamdouhaboammar/get-fable/fable-prove-it"><img src="https://agentmods.dev/badge/skills/immamdouhaboammar/get-fable/fable-prove-it/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for fable-prove-it

Your own site · 80×15
<a href="https://agentmods.dev/skills/immamdouhaboammar/get-fable/fable-prove-it"><img src="https://agentmods.dev/badge/skills/immamdouhaboammar/get-fable/fable-prove-it.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,231 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 $0.00055 $0.01231
Opus 5.5 $0.00022 $0.00492
Sonnet 5.5 $0.00011 $0.00246
Haiku 4.5 $0.00006 $0.00123

Measured 1mo ago against content hash 40661d96f7c3, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

fable-prove-it 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 1mo 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/fable-prove-it/SKILL.md · 110 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Files

What ships with it

3 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. 1mo ago First seen · 110 lines · 55 tokens per session scan A 40661d96f7c3

Subscribe to this mod's changes

fable-prove-it is a skill published in the GitHub repository imMamdouhaboammar/get-fable (2 stars, last pushed yesterday), licensed AGPL-3.0. It adds 55 tokens to every session and 1,231 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-21.

Related

Other skills, from other repositories

exploiting-jwt-algorithm-confusion-attack

Exploits JWT algorithm confusion vulnerabilities where the server's token verification library accepts the algorithm specified in the JWT header rather than enforcing a fixed algorithm. The tester manipulates the alg header to switch from RS256 to HS256 (using the RSA public key as the HMAC secret), sets alg to none…

xalgorix/xalgorix · 116 tokens

performing-api-security-testing-with-postman

Uses Postman to perform structured API security testing by building collections that test for OWASP API Security Top 10 vulnerabilities including authentication bypass, authorization flaws, injection, and data exposure. The tester creates environments with multiple user roles, writes test scripts for automated…

xalgorix/xalgorix · 106 tokens

performing-graphql-introspection-attack

Performs GraphQL introspection attacks to extract the full API schema including types, queries, mutations, subscriptions, and field definitions from GraphQL endpoints. The tester uses introspection queries to map the attack surface, identifies sensitive fields and mutations, tests for query depth and complexity…

xalgorix/xalgorix · 111 tokens

performing-soap-web-service-security-testing

Perform security testing of SOAP web services by analyzing WSDL definitions and testing for XML injection, XXE, WS-Security bypass, and SOAPAction spoofing.

xalgorix/xalgorix · 41 tokens

testing-api-authentication-weaknesses

Tests API authentication mechanisms for weaknesses including broken token validation, missing authentication on endpoints, weak password policies, credential stuffing susceptibility, token leakage in URLs or logs, and session management flaws. The tester evaluates JWT implementation, API key handling, OAuth flows, and…

xalgorix/xalgorix · 102 tokens

testing-api-for-mass-assignment-vulnerability

Tests APIs for mass assignment (auto-binding) vulnerabilities where clients can modify object properties they should not have access to by including additional parameters in API requests. The tester identifies writable endpoints, adds undocumented fields to request bodies (role, isAdmin, price, balance), and checks if…

xalgorix/xalgorix · 114 tokens