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-check/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-check)<a href="https://agentmods.dev/skills/fizzbee-io/fizzbee/fizz-check"><img src="https://agentmods.dev/badge/skills/fizzbee-io/fizzbee/fizz-check/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-check"><img src="https://agentmods.dev/badge/skills/fizzbee-io/fizzbee/fizz-check.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 117 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 | $0.00045 | $0.02479 |
| Opus 5.5 | $0.00018 | $0.00992 |
| Sonnet 5.5 | $0.00009 | $0.00496 |
| Haiku 4.5 | $0.00005 | $0.00248 |
Grade A, and why
fizz-check 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 — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.
FizzBee Model Checker
Installation
brew tap fizzbee-io/fizzbee && brew install fizzbee
Running
fizz spec.fizz # full model checking (exhaustive)
fizz -x --max_runs 1 --seed 42 spec.fizz # simulation (single random path)
Note: fizz is the installed binary. If building from source, use ./fizz (wrapper script in the repo root).
All Flags
| Flag | Default | Description |
|---|---|---|
-x / --simulation |
off | Simulation mode: single random path, fast |
--seed N |
0 | Random seed for reproducible simulation / random exploration |
--max_runs N |
0 (unlimited) | Number of simulation runs (simulation mode only) |
--exploration_strategy |
bfs |
State exploration: bfs, dfs, or random (model checking) |
--trace "line1\nline2" |
— | Guided trace: follow specific action sequence |
--trace-file FILE |
— | Load guided trace from file |
--trace-extend N |
0 | After trace, explore N more steps (shows enabled actions) |
--preinit-hook "STMT" |
— | Override constants before Init runs |
--preinit-hook-file FILE |
— | Load preinit hook from .cfg file |
--output-dir DIR |
auto-timestamped | Where to write output |
--no-copy-ast |
off | Don't copy AST to output dir |
--experimental_processed_queue |
off | EXPERIMENTAL: queue holds processed yield-points instead of unprocessed action-starts. Dedupes successors before they enter the queue → smaller peak queue memory (~10× on BFS, ~3× on DFS). State space and assertion outcomes unchanged under BFS. Under DFS / Random with max_actions set, exploration order differs and may visit a different subset within the bound — see Gotchas. |
Understanding Output
Model checking specs/counter.json
StateSpaceOptions: options:{max_actions:100 max_concurrent_actions:2}
Nodes: 12, queued: 0, elapsed: 2.1ms
Valid Nodes: 12 Unique states: 8
IsLive: true
PASSED: Model checker completed successfully
- Nodes: total graph nodes explored
- Valid Nodes: nodes that passed all safety assertions
- Unique states: distinct system states (after symmetry reduction)
- IsLive: liveness assertions passed
- PASSED / FAILED: overall result
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 · 247 lines · 45 tokens per session scan A 1233fafbdfa3
fizz-check is a skill published in the GitHub repository fizzbee-io/fizzbee (366 stars, last pushed yesterday), licensed Apache-2.0. It adds 45 tokens to every session and 2,479 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 2026-08-30.
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