webmcp

webmcp is a skill for Claude Code, Codex from webmaxru/is-ai-native. It costs 87 tokens per session (1,603 once invoked), scanned A, original, MIT.

A way for web applications to expose actions that an AI agent can call through the browser. It supports JavaScript or TypeScript apps and can connect those actions to HTML forms.

In plain words
What is it for?
Use it to expose browser tools, connect agent requests to form flows, handle agent-invoked submissions, and check whether WebMCP works in a web app.
Why use it?
It gives an agent a defined route into browser features instead of requiring it to guess how the page works. It also helps developers inspect and troubleshoot the connection between agent requests and form submissions.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/webmaxru/is-ai-native/webmcp
Any agent
npx skills add webmaxru/is-ai-native --skill webmcp
Clone the repo
git clone --depth 1 https://github.com/webmaxru/is-ai-native

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for webmcp

README.md
[![agentmods](https://agentmods.dev/badge/skills/webmaxru/is-ai-native/webmcp.svg)](https://agentmods.dev/skills/webmaxru/is-ai-native/webmcp)
Your own site
<a href="https://agentmods.dev/skills/webmaxru/is-ai-native/webmcp"><img src="https://agentmods.dev/badge/skills/webmaxru/is-ai-native/webmcp.svg" alt="Measured on agentmods" height="20"></a>
Per session 87 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,603 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00087 $0.01603
Opus 5 $0.00044 $0.00801
Sonnet 5 $0.00017 $0.00321
Haiku 4.5 $0.00009 $0.00160

Measured 3d ago against content hash c966dd40a881, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 3d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (assets/model-context-registry.template.ts, scripts/find-webmcp-targets.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.agents/skills/webmcp/SKILL.md · 71 lines

How it starts

The opening of the file, as written. The whole thing — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.

WebMCP

Procedures

Step 1: Identify the browser integration surface

  1. Inspect the workspace for browser entry points, UI handlers, and any existing app state or form handling layer.
  2. Execute node scripts/find-webmcp-targets.mjs . to inventory likely frontend files and existing WebMCP markers when a Node runtime is available.
  3. If a Node runtime is unavailable, inspect the nearest package.json, HTML entry point, and framework bootstrap files manually to identify the browser app boundary.
  4. If the workspace contains multiple frontend apps, prefer the app that contains the active route, component, or user-requested feature surface.
  5. If the inventory still leaves multiple plausible frontend targets, stop and ask the user which app should receive the WebMCP integration.
  6. If the project is not a browser web app, stop and explain that this skill does not apply.

Step 2: Choose the WebMCP shape

  1. Read references/webmcp-reference.md before writing code.
  2. Read references/declarative-api.md when the feature can be expressed as an HTML form flow or needs agent-invoked submit handling.
  3. Read references/compatibility.md when native availability, Chrome preview setup, or draft-versus-preview behavior matters.
  4. Read references/troubleshooting.md when registration, schema serialization, or agent-driven form execution fails.
  5. Verify that the integration runs in a secure window browsing context.
  6. If the feature must run on the server, in a worker, or headlessly without a visible browsing context, stop and explain the platform limitation.
  7. Choose the imperative API when the tool wraps existing JavaScript logic, requires dynamic registration, or needs ModelContextClient.requestUserInteraction().
  8. Choose the declarative API when the user flow already maps cleanly to a form submission and the page can keep the human-visible form in sync with agent activity.
  9. Keep tool names, descriptions, and parameters explicit and positive, and prefer atomic tools over overlapping variants.

Read the full file on GitHub · 71 lines

Files

What ships with it

6 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.

Changes

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.

  1. 3d ago First seen · 71 lines · 87 tokens per session scan A c966dd40a881

Subscribe to this mod's changes

webmcp is a skill published in the GitHub repository webmaxru/is-ai-native (5 stars, last pushed 12d ago), licensed MIT. It adds 87 tokens to every session and 1,603 once invoked, about $0.0004 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 2026-08-31.