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 instructions/cgaspard/webappmcp/claude-mdgit clone --depth 1 https://github.com/cgaspard/webappmcpWrote 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/cgaspard/webappmcp/claude-md)<a href="https://agentmods.dev/instructions/cgaspard/webappmcp/claude-md"><img src="https://agentmods.dev/badge/instructions/cgaspard/webappmcp/claude-md.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 | $0.02786 | $0.02786 |
| Opus 5 | $0.01393 | $0.01393 |
| Sonnet 5 | $0.00557 | $0.00557 |
| Haiku 4.5 | $0.00279 | $0.00279 |
Grade A, and why
webappmcp CLAUDE.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 4d 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 — 359 lines — stays where its author put it; the contents beside it link to each section on GitHub.
WebApp MCP Server - Development Guide
Project Overview
This project creates an MCP (Model Context Protocol) server that enables AI assistants to interact with web applications through a comprehensive set of tools. The server acts as a bridge between AI models and web applications, providing DOM inspection, user interaction simulation, and application state management capabilities.
Core Architecture
1. MCP Server Component
- Node.js-based MCP server that exposes tools for web application interaction
- Communicates with both backend Express middleware and frontend client
- Manages WebSocket connections for real-time DOM access
2. Express Middleware
- Installable as npm package dependency
- Integrates with existing Express applications
- Handles MCP server requests and routes them to appropriate handlers
- Manages WebSocket server for client connections
3. Frontend Client Library
- Framework-agnostic JavaScript library
- Supports React, Vue, Angular, and vanilla JS applications
- Establishes WebSocket connection to backend
- Executes DOM operations requested by MCP server
- Captures and transmits application state
Key Features
DOM Inspection Tools
- Query elements using CSS selectors
- Get element properties, attributes, and computed styles
- Traverse DOM tree (parents, children, siblings)
- Get text content and HTML structure
- Monitor DOM mutations
User Interaction Simulation
- Click elements
- Type text into input fields
- Submit forms
- Hover over elements
- Scroll page or elements
- Drag and drop operations
Application State Access
- Read JavaScript object properties
- Access component state (framework-specific)
- Monitor console logs
- Intercept network requests
- Access local storage and session storage
Visual Capture
- Take full page screenshots
- Capture specific element screenshots
- Record user interaction sequences
- Get element bounding boxes and positions
Implementation Details
Package Structure
webappmcp/
├── packages/
│ ├── server/ # MCP server implementation
│ ├── middleware/ # Express middleware
│ └── client/ # Frontend client library
├── examples/ # Example applications
└── docs/ # Documentation
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.
- 4d ago First seen · 359 lines · 2,786 tokens per session scan A 0a7f59b09d05
webappmcp CLAUDE.md is an instructions file published in the GitHub repository cgaspard/webappmcp (0 stars, last pushed 6mo ago), licensed MIT. It adds 2,786 tokens to every session, about $0.0139 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.
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).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
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.