Borrowing it
Nothing to install: this file belongs to agentcathq/webmcp-react. 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/agentcathq/webmcp-react/main/AGENTS.mdgit clone --depth 1 https://github.com/agentcathq/webmcp-reactWrote 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/agentcathq/webmcp-react/agents-md)<a href="https://agentmods.dev/instructions/agentcathq/webmcp-react/agents-md"><img src="https://agentmods.dev/badge/instructions/agentcathq/webmcp-react/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/agentcathq/webmcp-react/agents-md"><img src="https://agentmods.dev/badge/instructions/agentcathq/webmcp-react/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 | $0.01694 | $0.01694 |
| Opus 5.5 | $0.00678 | $0.00678 |
| Sonnet 5.5 | $0.00339 | $0.00339 |
| Haiku 4.5 | $0.00169 | $0.00169 |
Grade A, and why
webmcp-react 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 — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
This file is for AI agents contributing to the webmcp-react library. For integrating webmcp-react into your app, see the skills/ directory.
Reference
- WebMCP standard: https://github.com/webmachinelearning/webmcp — the W3C spec this library implements
- API reference:
docs/api.md— this library's full API docs
Commands
| Task | Command |
|---|---|
| Install | pnpm install |
| Build | pnpm build |
| Test | pnpm test |
| Test (watch) | pnpm test:watch |
| Test (single file) | pnpm test -- path/to/file.test.tsx |
| Type check | pnpm typecheck |
| Lint | pnpm lint |
| Lint + fix | pnpm lint:fix |
| Full check before PR | pnpm build && pnpm typecheck && pnpm lint && pnpm test |
Project Structure
src/ ← core library (your focus)
├── index.ts ← public API exports
├── types.ts ← all TypeScript types
├── context.tsx ← WebMCPProvider + useWebMCPStatus hook
├── hooks/
│ └── useMcpTool.ts ← main hook for tool registration
├── polyfill/ ← document.modelContext polyfill
│ ├── index.ts ← installPolyfill / cleanupPolyfill + polyfill marker
│ ├── registry.ts ← in-memory tool storage
│ ├── execute.ts ← shared execution engine (signals, serialization, errors)
│ ├── testing-shim.ts ← DEPRECATED wrapper over execute.ts (removed in 2.0.0)
│ └── validation.ts ← input validation against JSON Schema
└── utils/
├── schema.ts ← Zod → JSON Schema conversion + schema fingerprinting
└── warn.ts ← dev-only fire-once warnings
Other directories (don't modify unless explicitly asked):
extension/— Chrome extension that bridges web tools to desktop MCP clientsexamples/playground/— Wordle demo showcasing dynamic tool registrationexamples/nextjs/— Next.js integration exampleskills/— agent skills for consumers of the librarydocs/api.md— full API reference
Architecture Decisions — Don't "Fix" These
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 · +1 lines · +46 tokens per session ff673781d1bd
- 2mo ago Changed · +6 lines · +245 tokens per session 98eaa58cfe2c
- 2mo ago First seen · 104 lines · 1,403 tokens per session scan A c26e8abc6c4a
webmcp-react AGENTS.md is an instructions file published in the GitHub repository agentcathq/webmcp-react (92 stars, last pushed 10d ago), licensed MIT. It adds 1,694 tokens to every session, about $0.0068 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.
webmcp-react AGENTS.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| webmcp-react AGENTS.mdagentcathq/webmcp-react | Instructions file | 92 | 10d ago | MIT | A | 1,694 | Codex, OpenCode |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | yesterday | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |