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 react-router-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/react-router-code-review)<a href="https://agentmods.dev/skills/existential-birds/beagle/react-router-code-review"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/react-router-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/react-router-code-review"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/react-router-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 | $0.00043 | $0.00930 |
| Opus 5.5 | $0.00017 | $0.00372 |
| Sonnet 5.5 | $0.00009 | $0.00186 |
| Haiku 4.5 | $0.00004 | $0.00093 |
Grade A, and why
react-router-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 — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Router Code Review
Quick Reference
| Issue Type | Reference |
|---|---|
| useEffect for data, missing loaders, params | references/data-loading.md |
| Form vs useFetcher, action patterns | references/mutations.md |
| Missing error boundaries, errorElement | references/error-handling.md |
| navigate() vs Link, pending states | references/navigation.md |
Review Checklist
- Data loaded via
loadernotuseEffect - Route params accessed type-safely with validation
- Using
defer()for parallel data fetching when appropriate - Mutations use
<Form>oruseFetchernot manual fetch - Actions handle both success and error cases
- Error boundaries with
errorElementon routes - Using
isRouteErrorResponse()to check error types - Navigation uses
<Link>overnavigate()where possible - Pending states shown via
useNavigation()orfetcher.state - No navigation in render (only in effects or handlers)
Valid Patterns (Do NOT Flag)
These patterns are correct React Router usage - do not report as issues:
- useEffect for client-only data - Loaders run server-side; localStorage, window dimensions, and browser APIs must use useEffect
- navigate() in event handlers - Link is for declarative navigation; navigate() is correct for imperative navigation in callbacks/handlers
- Type annotation on loader data -
useLoaderData<typeof loader>()is a type annotation, not a type assertion - Empty errorElement at route level - Route may intentionally rely on parent error boundary
- Form without action prop - Posts to current URL by convention; explicit action is optional
- loader returning null - Valid when data may not exist; null is a legitimate loader return value
- Using fetcher.data without checking fetcher.state - May be intentional when stale data is acceptable during revalidation
What ships with it
4 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 · 87 lines · 43 tokens per session scan A 7ec906ac53e4
react-router-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 43 tokens to every session and 930 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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