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/mcp-plugins/mcp-proxy-wrapper/claude-mdgit clone --depth 1 https://github.com/mcp-plugins/mcp-proxy-wrapperWhat 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 | $0.00749 | $0.00749 |
| Opus 5 | $0.00375 | $0.00375 |
| Sonnet 5 | $0.00150 | $0.00150 |
| Haiku 4.5 | $0.00075 | $0.00075 |
Grade A, and why
mcp-proxy-wrapper 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 2d 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 — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Project Overview
This is the MCP Proxy Wrapper - a TypeScript library that provides a hook system for intercepting and modifying tool calls in Model Context Protocol (MCP) servers. The library wraps existing MCP server instances without requiring backend infrastructure changes.
Core Architecture
Main Components
src/proxy-wrapper.ts: Core wrapper functionality that intercepts MCP server tool registrationssrc/interfaces/proxy-hooks.ts: TypeScript interfaces for hooks and configurationsrc/utils/logger.ts: Logging utility with configurable levels and colored outputsrc/index.ts: Main entry point that exports all public APIs
Hook System
The proxy wrapper implements a hook system with two main phases:
- beforeToolCall: Executes before tool calls, can modify arguments or short-circuit execution
- afterToolCall: Executes after tool calls, can modify results
The wrapper intercepts the server.tool() method to inject hook execution around the original tool handlers.
Development Commands
Build and Test
npm run build # Compile TypeScript to dist/
npm test # Run Jest test suite
npm run lint # Run ESLint on TypeScript files
npm run format # Format code with Prettier
Running Individual Tests
npm test -- src/proxy-wrapper.test.ts # Run specific test file
node src/proxy-wrapper.simple.test.js # Run JavaScript test directly
Development Workflow
npm run prepare # Runs build automatically
npm run prepublishOnly # Runs tests and lint before publishing
Key Technical Details
Module System
- Uses ES modules (
"type": "module"in package.json) - TypeScript config targets ES2022 with NodeNext module resolution
- Jest configured for ESM with ts-jest transform
Dependencies
- Runtime:
@modelcontextprotocol/sdk,zod - Development: TypeScript, Jest, ESLint, Prettier
- Peer Dependencies:
@modelcontextprotocol/sdk(must be provided by consuming application)
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.
- 2d ago First seen · 89 lines · 749 tokens per session scan A 5de64db4fccb
mcp-proxy-wrapper CLAUDE.md is an instructions file published in the GitHub repository mcp-plugins/mcp-proxy-wrapper (5 stars, last pushed 1y ago), licensed MIT. It adds 749 tokens to every session, about $0.0037 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.
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