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.
npx skills add imMamdouhaboammar/get-fable --skill fable-simulatorgit clone --depth 1 https://github.com/imMamdouhaboammar/get-fableWrote 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.
[](https://agentmods.dev/skills/immamdouhaboammar/get-fable/fable-simulator)<a href="https://agentmods.dev/skills/immamdouhaboammar/get-fable/fable-simulator"><img src="https://agentmods.dev/badge/skills/immamdouhaboammar/get-fable/fable-simulator/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.
<a href="https://agentmods.dev/skills/immamdouhaboammar/get-fable/fable-simulator"><img src="https://agentmods.dev/badge/skills/immamdouhaboammar/get-fable/fable-simulator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00114 | $0.01441 |
| Opus 5 | $0.00057 | $0.00720 |
| Sonnet 5 | $0.00023 | $0.00288 |
| Haiku 4.5 | $0.00011 | $0.00144 |
Grade A, and why
fable-simulator 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 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.
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.
How it starts
The opening of the file, as written. The whole thing — 169 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Fable Simulator
Create an independent model of expected behavior and compare it with the candidate without pretending the simulation itself is production evidence.
Mission
Simulation is useful when ordinary tests risk sharing the same assumptions as the implementation, when a UI/agent flow needs controlled playthrough, or when failure injection can expose paths that are hard to reproduce safely.
The Skill must preserve a hard boundary between simulated/oracle evidence and real runtime verification.
Activate When
- an algorithm/rewrite needs an independently derived oracle;
- a contract is implicit across callers and needs reconstruction;
- UI/agent state transitions benefit from scripted playthrough/failure injection;
- testing destructive/rare conditions safely requires a model/sandbox;
- differential testing between two independent implementations is valuable.
Do Not Activate When
- normal tests/runtime evidence already proves the claim cheaply;
- the proposed oracle is derived from the same code/assumptions under test;
- simulation would be reported as proof that an external production system actually behaved that way.
Simulation Classification
| Mode | Independence requirement |
|---|---|
| Golden fixtures | fixture expected outputs come from trusted contract/observations |
| Reference implementation | independently written/maintained logic |
| Differential provider/model | separate implementation/model with blinded oracle |
| State-machine simulation | transitions/invariants defined from product contract |
| Failure injection | controlled faults with explicit modeled assumptions |
| UI playthrough | browser actions + observable DOM/network/runtime evidence |
Protocol
Stage 1 — Define the claim and oracle independence
State what candidate behavior is being checked and why the oracle does not simply repeat candidate logic.
List shared assumptions. If a shared assumption could cause both candidate and oracle to be wrong identically, record that coverage gap.
What ships with it
7 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.
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.
- 5d ago First seen · 169 lines · 114 tokens per session scan A 8004248fb9d2
fable-simulator is a skill published in the GitHub repository imMamdouhaboammar/get-fable (4 stars, last pushed today), licensed MIT. It adds 114 tokens to every session and 1,441 once invoked, about $0.0006 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 2026-09-05.
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