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 jxoesneon/Ciel --skill rust-developmentgit clone --depth 1 https://github.com/jxoesneon/CielWrote 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/jxoesneon/ciel/rust-development)<a href="https://agentmods.dev/skills/jxoesneon/ciel/rust-development"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/rust-development/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/jxoesneon/ciel/rust-development"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/rust-development.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 | $0.00022 | $0.00448 |
| Opus 5.5 | $0.00009 | $0.00179 |
| Sonnet 5.5 | $0.00004 | $0.00090 |
| Haiku 4.5 | $0.00002 | $0.00045 |
Grade A, and why
rust-development 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
CIEL ADAPTATION: Rust Development (Safety & Performance)
This skill formalizes the development of high-integrity Rust applications. it prioritizes ownership-aware design and making illegal states unrepresentable.
Idiomatic Standards
- Ownership & Borrowing: Pass
&T(borrow) by default. Clone ONLY when ownership is required and cannot be moved. - Error Handling:
- Apps: Use
anyhowfor flexible error propagation with context. - Libraries: Use
thiserrorfor structured, typed error variants. - Hard Gate: Prohibit
.unwrap()or.expect()in production/library code. Use?orunwrap_or.
- Apps: Use
- Type-Driven Design: Use
enumand exhaustive matching to eliminate illegal states. Use the "Newtype" pattern for primitive safety.
Architecture & Traits
- Trait Bounds: Use
impl Traitfor inputs. UseBox<dyn Trait>only when dynamic dispatch is required. - Async (Tokio): Enforce
tokio::spawnfor concurrent tasks. Never block an async executor withstd::thread::sleep. - Visibility: Expose minimally. Prefer
pub(crate)overpub.
TDD & Verification
- Doc Tests: Include executable examples in doc comments for all public APIs.
- Property-Based Testing: Use
proptestfor input validation and complex state transitions. - LLVM Cov: Target 80%+ coverage using
cargo llvm-cov.
Anti-Patterns
- Wildcard Matching: Using
_ => {}in business-critical enums (hides new variants). - String over &str: Using
Stringfor read-only function parameters. - Unsafe Without Reason: Using
unsafewithout a// SAFETY:comment explaining the invariant.
What ships with it
1 file 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.
- 1mo ago Changed · -13 lines bd6fad44f53b
- 1mo ago First seen · 53 lines · 22 tokens per session scan A 9ab997092cdb
rust-development is a skill published in the GitHub repository jxoesneon/Ciel (1 stars, last pushed 2d ago), licensed Apache-2.0. It adds 22 tokens to every session and 448 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 2026-09-03.
Other skills, from other repositories
rust-testing
Rust testing patterns including unit tests, integration tests, async testing, property-based testing, mocking, and coverage. Follows TDD methodology.
java-testing-junit-mockito
Use when writing tests for Java (Quarkus or Spring) code - JUnit Jupiter structure, Mockito for collaborators, test slices, Testcontainers, and framework-native integration tests, test-first.
python-testing
Python testing strategies using pytest, TDD methodology, fixtures, mocking, parametrization, and coverage requirements.
rust-test
Enforce TDD workflow for Rust. Write tests first, then implement. Verify 80%+ coverage with cargo-llvm-cov.
rust-testing
Rust testing patterns including unit tests, integration tests, async testing, property-based testing, mocking, and coverage. Follows TDD methodology.
tdd-rust
TDD workflow for RTK filter development. Red-Green-Refactor with Rust idioms. Real fixtures, token savings assertions, snapshot tests with insta. Auto-triggers on new filter implementation.