Borrowing it
Nothing to install: this file belongs to fizzbee-io/fizzbee. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/fizzbee-io/fizzbee/main/.claude/skills/fizz-mbt/SKILL.mdgit clone --depth 1 https://github.com/fizzbee-io/fizzbeeWrote 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/fizzbee-io/fizzbee/fizz-mbt)<a href="https://agentmods.dev/skills/fizzbee-io/fizzbee/fizz-mbt"><img src="https://agentmods.dev/badge/skills/fizzbee-io/fizzbee/fizz-mbt/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/fizzbee-io/fizzbee/fizz-mbt"><img src="https://agentmods.dev/badge/skills/fizzbee-io/fizzbee/fizz-mbt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00077 | $0.02473 |
| Opus 5.5 | $0.00031 | $0.00989 |
| Sonnet 5.5 | $0.00015 | $0.00495 |
| Haiku 4.5 | $0.00008 | $0.00247 |
Grade A, and why
fizz-mbt 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 2mo 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 — 296 lines — stays where its author put it; the contents beside it link to each section on GitHub.
FizzBee Model-Based Testing (MBT)
FizzBee MBT generates exhaustive test sequences from a verified Fizz spec and runs them against the real system under test (SUT).
Examples: https://github.com/fizzbee-io/fizzbee-mbt-examples
Installation
# fizzbee (model checker)
brew tap fizzbee-io/fizzbee && brew install fizzbee
# fizzbee-mbt (test runner + server)
brew tap fizzbee-io/fizzbee-mbt && brew install fizzbee-mbt
Language Support Overview
| Feature | TypeScript | Go | Rust | Java |
|---|---|---|---|---|
| Sequential testing | ✓ | ✓ | ✓ | ✓ |
| Concurrent testing | ✓ (cooperative) | ✓ | ✓ | ✓ |
| StateGetter | ✓ | ✓ | ✓ | ✓ |
| SnapshotStateGetter | ✓ | ✓ | ✓ | ✓ |
| Sentinel values (IGNORE) | ✓ | ✓ | ✓ | ✓ |
| AfterActionHook | ✓ | — | — | — |
| OverridesProvider (fuzzing) | ✓ | — | — | — |
| Playwright utilities | ✓ | — | — | — |
TypeScript and Go have the broadest feature support. TypeScript is the primary language for UI/E2E testing.
Workflow
- Write and verify the
.fizzspec:fizz spec.fizz→ PASSED - Scaffold:
fizz mbt-scaffold --lang <lang> --gen-adapter --out-dir <dir> spec.fizz - Implement the adapter methods
- Start the MBT server:
fizzbee-mbt-server --states_file out/run_<timestamp>/ - Run tests
Scaffold Commands
# TypeScript
fizz mbt-scaffold --lang typescript --gen-adapter --out-dir src/fizztests/ spec.fizz
# Go
fizz mbt-scaffold --lang go --go-package myapp --gen-adapter --out-dir fizztests/ spec.fizz
# Rust
fizz mbt-scaffold --lang rust --gen-adapter --out-dir src/fizztests/ spec.fizz
# Java
fizz mbt-scaffold --lang java --java-package org.example.myapp --gen-adapter --out-dir fizztests/ spec.fizz
Three files are generated per spec:
| File | Description | Edit? |
|---|---|---|
*_interfaces.ts/go/rs/java |
Role + model interfaces from spec | No |
*_adapters.ts/go/rs/java |
Stub methods to implement | Yes |
*_test.ts/go/rs/java |
Test runner wiring | No |
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.
- 2mo ago First seen · 296 lines · 77 tokens per session scan A f7f01d586a62
fizz-mbt is a skill published in the GitHub repository fizzbee-io/fizzbee (366 stars, last pushed yesterday), licensed Apache-2.0. It adds 77 tokens to every session and 2,473 once invoked, about $0.0003 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 2026-08-30.
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