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 thewolffish/wolffish-app --skill filesystemgit clone --depth 1 https://github.com/thewolffish/wolffish-appWrote 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/thewolffish/wolffish-app/filesystem)<a href="https://agentmods.dev/skills/thewolffish/wolffish-app/filesystem"><img src="https://agentmods.dev/badge/skills/thewolffish/wolffish-app/filesystem/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/thewolffish/wolffish-app/filesystem"><img src="https://agentmods.dev/badge/skills/thewolffish/wolffish-app/filesystem.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 | $0.00013 | $0.01478 |
| Opus 5 | $0.00006 | $0.00739 |
| Sonnet 5 | $0.00003 | $0.00296 |
| Haiku 4.5 | $0.00001 | $0.00148 |
Grade A, and why
filesystem 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 8d 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.
What it actually says
Filesystem
Interface
- Tools:
file_read,file_write,file_patch,image_view - Paths may use
~for the user's home directory. - Writes always create parent directories as needed.
Rules
- Verify before reading. Before calling
file_read, confirm the file exists — use a directory listing,file_readon the parent dir, or prior context that proves the path is real. Skip the check only when you have high certainty the file exists (e.g. you just created it, it appeared in a recent directory listing, or the user pasted its path). Never guess a path and attempt the read blind. - Read before you write. Use
file_readto see what's there before editing. - Prefer
file_patchfor surgical edits — it preserves the rest of the file exactly as the user wrote it. - For
file_patch, thefindstring must match exactly (whitespace included). - Never write to system paths (
/etc/,/usr/,/private/) without asking — the safety gate will prompt the user, but be transparent about what you're doing first. - When showing file contents back to the user, format them as a code block.
What ships with it
2 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.
- 8d ago First seen · 194 lines · 13 tokens per session scan A ad8d79e6bb30
filesystem is a skill published in the GitHub repository thewolffish/wolffish-app (5 stars, last pushed 2d ago), licensed MIT. It adds 13 tokens to every session and 1,478 once invoked, about $0.0001 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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