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 existential-birds/beagle --skill rust-best-practicesgit clone --depth 1 https://github.com/existential-birds/beagleWrote 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/existential-birds/beagle/rust-best-practices)<a href="https://agentmods.dev/skills/existential-birds/beagle/rust-best-practices"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/rust-best-practices/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/existential-birds/beagle/rust-best-practices"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/rust-best-practices.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 | $0.00091 | $0.02704 |
| Opus 5.5 | $0.00036 | $0.01082 |
| Sonnet 5.5 | $0.00018 | $0.00541 |
| Haiku 4.5 | $0.00009 | $0.00270 |
Grade A, and why
rust-best-practices 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.
How it starts
The opening of the file, as written. The whole thing — 100 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Rust Best Practices
Guidance for writing idiomatic, performant, and safe Rust code. This is a development skill, not a review skill -- use it when building, not reviewing.
Quick Reference
| Topic | Key Rule | Reference |
|---|---|---|
| Ownership | Borrow by default, clone only when you need a separate owned copy | references/coding-idioms.md |
| Clippy | Run cargo clippy -- -D warnings on every commit; configure workspace lints |
references/clippy-config.md |
| Performance | Don't guess, measure. Profile with --release first. Watch monomorphization + cache-line alignment at scale |
references/performance.md |
| Generics | Static dispatch by default, dynamic dispatch when you need mixed types | references/generics-dispatch.md |
| Type State | Encode state in the type system when invalid operations should be compile errors | references/type-state-pattern.md |
| Documentation | // for why, /// for what and how, //! for module/crate purpose |
references/documentation.md |
| Pointers | Choose pointer types based on ownership needs and threading model | references/pointer-types.md |
| API Design | Unsurprising, flexible, obvious, constrained — encode invariants in types; watch hidden contracts (re-exports, auto-traits) | references/api-design.md |
| Wild Patterns | Drop guards, extension traits, index pointers, crate preludes — battle-tested idioms from mature crates | references/coding-idioms.md |
| Ecosystem | Evaluate crates, pick error handling strategy, stay current | references/ecosystem-patterns.md |
Gates
Short sequences with pass conditions before claiming outcomes that need evidence (not an internal “I checked”).
What ships with it
9 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.
- references/api-design.md 15 KB
- references/clippy-config.md 4.0 KB
- references/coding-idioms.md 14 KB
- references/documentation.md 5.5 KB
- references/ecosystem-patterns.md 5.5 KB
- references/generics-dispatch.md 9.9 KB
- references/performance.md 10 KB
- references/pointer-types.md 5.1 KB
- references/type-state-pattern.md 3.5 KB
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 · 100 lines · 91 tokens per session scan A 56682e1e6dc3
rust-best-practices is a skill published in the GitHub repository existential-birds/beagle (82 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 91 tokens to every session and 2,704 once invoked, about $0.0004 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 2026-09-16.
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