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 agentmods add skills/clubpay/ronykit/webmcpnpx skills add clubpay/ronykit --skill webmcpgit clone --depth 1 https://github.com/clubpay/ronykitWrote 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/clubpay/ronykit/webmcp)<a href="https://agentmods.dev/skills/clubpay/ronykit/webmcp"><img src="https://agentmods.dev/badge/skills/clubpay/ronykit/webmcp.svg" alt="Measured on agentmods" 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 | $0.00069 | $0.02370 |
| Opus 5 | $0.00034 | $0.01185 |
| Sonnet 5 | $0.00014 | $0.00474 |
| Haiku 4.5 | $0.00007 | $0.00237 |
Grade A, and why
webmcp 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 5d 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 — 217 lines — stays where its author put it; the contents beside it link to each section on GitHub.
WebMCP (agent-friendly frontend)
Expose your app's real business logic as structured tools agents can discover and call — instead of clicking buttons or scraping the DOM.
Every agent-ready page ships two interfaces:
- Human UI — the existing components, forms, and navigation.
- Agent tool surface — named tools with JSON Schemas that call the same handlers, stores, and API clients the UI uses.
Keep one source of truth. If a human click and an agent tool call would diverge, fix the architecture before adding more tools.
When to use
- Adding WebMCP /
document.modelContextsupport to a React or Next.js app. - Designing tool names, schemas, and descriptions for dashboards, admin consoles, or operational UIs.
- Making filters, search, CRUD, navigation, or checkout flows agent-callable.
- Reviewing whether a frontend is safe and reliable for AI agents.
Combine with nextjs-modern (App Router boundaries), dashboard-ui (tool
granularity for admin screens), ux-quality (human + agent UI stay in sync),
and frontend-testing (verify tools, not just components).
WebMCP vs related protocols
| Surface | What it is | When to use |
|---|---|---|
WebMCP (document.modelContext) |
W3C draft: page registers client-side tools for in-browser agents | Your website exposes what it can do while the user has the tab open |
| MCP (Model Context Protocol) | Server protocol: tools on a backend or desktop process | Backend services, DBs, CLIs — not a substitute for live page state |
| mcp-dashboards | MCP server that renders charts inside AI chat clients | Visualize data in the conversation — complementary, not WebMCP |
| DOM automation (Playwright, etc.) | Agent guesses selectors | Last resort when no tools exist; brittle and slow |
WebMCP is not a replacement for your REST/OpenAPI backend. Agents still need auth, rate limits, and server validation. Tools are a typed façade over logic you already run in the browser.
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.
- 5d ago First seen · 217 lines · 69 tokens per session scan A dad747b5f752
webmcp is a skill published in the GitHub repository clubpay/ronykit (38 stars, last pushed 4d ago), licensed BSD-3-Clause. It adds 69 tokens to every session and 2,370 once invoked, about $0.0003 per session on Opus 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.
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