React Router is a routing system for React applications that maps URLs to the interface shown on screen. Developers use it either as a small library within their own application structure or as part of a full React framework.
Borrowing it
Nothing to install: this file belongs to remix-run/react-router. 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/remix-run/react-router/main/AGENTS.mdgit clone --depth 1 https://github.com/remix-run/react-routerWrote 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/instructions/remix-run/react-router/agents-md)<a href="https://agentmods.dev/instructions/remix-run/react-router/agents-md"><img src="https://agentmods.dev/badge/instructions/remix-run/react-router/agents-md/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/instructions/remix-run/react-router/agents-md"><img src="https://agentmods.dev/badge/instructions/remix-run/react-router/agents-md.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 | $0.01820 | $0.01820 |
| Opus 5.5 | $0.00728 | $0.00728 |
| Sonnet 5.5 | $0.00364 | $0.00364 |
| Haiku 4.5 | $0.00182 | $0.00182 |
Grade A, and why
react-router AGENTS.md 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 — 159 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Router Development Guide
Commands
- Build:
pnpm build(all packages) orpnpm run --filter <package> build(single package) - Test (Jest):
pnpm test(all packages),pnpm test packages/<package>/(single package),pnpm test packages/react-router/__tests__/router/fetchers-test.ts(single file), orpnpm test -- -t "action fetch"(tests matching name) - Integration tests (Playwright):
pnpm test:integration --project chromium(build + test all),pnpm test:integration:run --project chromium(test only, all),pnpm test:integration:run integration/middleware-test.ts --project chromium(single file), orpnpm test:integration:run --project chromium -g "middleware"(tests matching name) - Typecheck:
pnpm run typecheck - Lint:
pnpm run lint - Docs generation:
pnpm run docs(regenerates API docs from JSDoc) - Type generation:
pnpm run typegen(Framework Mode only) - Clean:
pnpm run clean(git clean -fdX)
Modes
Five distinct modes: Declarative, Data, Framework, RSC Data (unstable), RSC Framework (unstable). Always identify which mode(s) a feature applies to.
- Declarative:
<BrowserRouter>,<Routes>,<Route> - Data:
createBrowserRouter()withloader/action,<RouterProvider> - Framework: Vite plugin +
routes.ts+ Route Module API (route exports likeloader,action,default) + type generation + SSR/SPA - RSC Data (unstable): RSC runtime APIs, manual bundler setup, runtime route config
- RSC Framework (unstable): Framework Mode with
unstable_reactRouterRSCVite plugin
RSC mode differences:
- RSC Framework:
unstable_reactRouterRSCplugin,@vitejs/plugin-rsc, different entry points/format - RSC Data: Manual bundler, runtime route config typically in
src/routes.ts,unstable_RSCRouteConfig, different runtime APIs,setupRscTestinintegration/rsc/
Architecture
- Monorepo: pnpm workspace, packages in
packages/ - Key packages:
react-router: Core (all modes) -lib/components.tsx,lib/hooks.tsx,lib/router/,lib/dom/,lib/rsc/@react-router/dev: Framework tooling -vite/plugin.ts(Framework),vite/rsc/plugin.ts(RSC Framework),typegen/@react-router/node,@react-router/cloudflare,@react-router/express: Server adapters@react-router/serve: Minimal server for Framework Mode@react-router/fs-routes: File-system routing (flatRoutes())
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 · 159 lines · 1,820 tokens per session scan A 26d0b881712b
react-router AGENTS.md is an instructions file published in the GitHub repository remix-run/react-router (56,622 stars, last pushed today), licensed MIT. It adds 1,820 tokens to every session, about $0.0073 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 instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).