Deno is a runtime that executes JavaScript, TypeScript, and WebAssembly programs outside a browser. Developers use it for applications such as web servers, and the catalogue add-ons provide workflows and guidance for Deno projects.
Borrowing it
Nothing to install: this file belongs to denoland/deno. 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/denoland/deno/main/.claude/skills/fmt/SKILL.mdgit clone --depth 1 https://github.com/denoland/denoWrote 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/denoland/deno/fmt)<a href="https://agentmods.dev/skills/denoland/deno/fmt"><img src="https://agentmods.dev/badge/skills/denoland/deno/fmt/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/denoland/deno/fmt"><img src="https://agentmods.dev/badge/skills/denoland/deno/fmt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Snyk pass
- 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 | $0.00018 | $0.00071 |
| Opus 5.5 | $0.00007 | $0.00028 |
| Sonnet 5.5 | $0.00004 | $0.00014 |
| Haiku 4.5 | $0.00002 | $0.00007 |
Grade A, and why
fmt 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.
What it actually says
Format Code
Run the Deno code formatter:
./x fmt
If any files were changed, stage and report them.
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.
- 1mo ago First seen · 17 lines · 18 tokens per session scan A edcdabf67eae
fmt is a skill published in the GitHub repository denoland/deno (108,724 stars, last pushed today), licensed MIT. It adds 18 tokens to every session and 71 once invoked, about $0.0001 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.
Other skills, from other repositories
ax-rust-signature
Use when writing Rust code with axllm for string signatures, field descriptors, JSON schema output, validation, and typed tool argument shapes.
ax-rust-llm
Use when writing Rust code with axllm for using the generated Ax package, factory functions, package docs, examples, and API reference.
ax-rust-gepa
Use when writing Rust code with axllm for GEPA, Pareto tradeoffs, reflection clients, metric budgets, optimizer state, and artifacts.
ax-rust-agent-context
Use when writing Rust code with axllm for deciding between context maps, trajectory context policy, offline optimization (ACE/GEPA), and memory recall for long-context agents.
ax-rust-refine
Use when writing Rust code with axllm for reward-scored generation, iterative candidate improvement, evaluator feedback, and optimizer-backed refinement patterns.
ax-rust-ai
Use when writing Rust code with axllm for named deployment profiles, generic provider clients, model selection, OpenAI-compatible calls, Responses, Gemini, Anthropic, routers, and balancers.