Borrowing it
Nothing to install: this file belongs to JoviDeCroock/preact-mcp. 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/JoviDeCroock/preact-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/JoviDeCroock/preact-mcpWrote 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/jovidecroock/preact-mcp/claude-md)<a href="https://agentmods.dev/instructions/jovidecroock/preact-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/jovidecroock/preact-mcp/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 5.1 | $0.01392 | $0.01392 |
| Opus 5 | $0.00696 | $0.00696 |
| Sonnet 5 | $0.00278 | $0.00278 |
| Haiku 4.5 | $0.00139 | $0.00139 |
Grade A, and why
preact-mcp 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 8d 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 — 202 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Claude Documentation - Preact MCP Server
This document contains technical details and learnings about the Preact MCP Server implementation for Claude Code.
Project Overview
The Preact MCP Server is a Model Context Protocol implementation that provides Claude with access to Preact ecosystem documentation. It aggregates information from multiple Preact repositories to answer questions about Preact, Preact-ISO, and Signals.
Architecture
Core Components
1. MCP Server (src/index.ts)
- Purpose: Main server implementation using the MCP SDK
- Key Features:
- Stdio transport for communication with Claude
- Tool registration and request handling
- Error handling and validation
- Tools Exposed:
query_preact_docs: Multi-repository documentation searchget_preact_readme: Repository-specific README retrievallist_preact_repositories: Available repository enumeration
2. Data Source (src/datasource.ts)
- Purpose: Handles data fetching and caching from GitHub
- Key Features:
- HTTP caching with 5-minute TTL to respect rate limits
- Text search with context extraction
- Error handling for network failures
- Support for multiple repository sources
Repository Sources
The server queries these Preact ecosystem repositories:
-
preact/preact: Core Preact library
- README:
https://raw.githubusercontent.com/preactjs/preact/refs/heads/main/README.md - Description: Fast 3kB React alternative
- README:
-
preact/preact-iso: Isomorphic utilities
- README:
https://raw.githubusercontent.com/preactjs/preact-iso/refs/heads/main/README.md - Description: SSR and hydration utilities
- README:
-
preact/signals: Reactive state management
- README:
https://raw.githubusercontent.com/preactjs/signals/refs/heads/main/README.md - Description: Fine-grained reactivity system
- README:
Technical Implementation Details
Search Algorithm
- Performs case-insensitive substring matching
- Returns context (2 lines before/after matches)
- Limits results to 10 matches per repository
- Formats results with markdown code blocks
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.
- 8d ago First seen · 202 lines · 1,392 tokens per session scan A 8eaf51cc0765
preact-mcp CLAUDE.md is an instructions file published in the GitHub repository JoviDeCroock/preact-mcp (2 stars, last pushed 1y ago), licensed MIT. It adds 1,392 tokens to every session, about $0.0070 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
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langchain AGENTS.md
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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.