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 serde-code-reviewgit 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/serde-code-review)<a href="https://agentmods.dev/skills/existential-birds/beagle/serde-code-review"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/serde-code-review/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/serde-code-review"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/serde-code-review.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 | $0.00058 | $0.01704 |
| Opus 5.5 | $0.00023 | $0.00682 |
| Sonnet 5.5 | $0.00012 | $0.00341 |
| Haiku 4.5 | $0.00006 | $0.00170 |
Grade A, and why
serde-code-review 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 — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Serde Code Review
Review Workflow
- Check Cargo.toml — Note serde features (
derive,rc), format crates (serde_json,toml,bincode, etc.), and Rust edition (2024 has breaking changes affecting serde code) - Check derive usage — Verify
SerializeandDeserializeare derived appropriately - Check enum representations — Enum tagging affects wire format compatibility and readability
- Check field attributes — Renaming, defaults, skipping affect API contracts
- Check edition 2024 compatibility — Reserved
genkeyword, RPIT lifetime capture changes,never_type_fallback - Verify round-trip correctness — Serialized data must deserialize back to the same value
Gates (before reporting findings)
Run in order. Do not write a finding until the step that applies has passed.
-
Serde context on disk — Pass when: You have read the relevant
Cargo.toml(crate or workspace root) and can state Rustedition,serde/serde_derivefeatures if non-default (derive,rc), and which format crates apply (serde_json,toml,bincode, etc.) for the code under review. Then apply edition-specific checklist items (e.g.gen, RPIT/never_type_fallback) only when that file supports them. -
Per-finding evidence — Pass when: Each issue cites
[FILE:LINE]from the current tree for thestruct/enum,Serialize/Deserializeimpl, or attribute block in question (not from memory, docs-only, or another branch). -
Category check vs protocol — Pass when: For the finding type (derive attrs, enum tagging,
flatten, custom impl, sqlx + serde alignment), you ran the matching checks from the review-verification-protocol skill (e.g. full type definition + serde attrs before “wrong representation”; confirmed edition inCargo.tomlbefore edition-2024-only findings). Then add the finding. -
Output shape — Pass when: The report lines match Output Format below (severity + description).
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.
- 1mo ago First seen · 120 lines · 58 tokens per session scan A 25b0bfd15d48
serde-code-review is a skill published in the GitHub repository existential-birds/beagle (82 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 58 tokens to every session and 1,704 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 2026-09-16.
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