What is mcproxy CLAUDE.md?

A project-guidance document for mcproxy, a tool that sits between Claude Code and external tool servers and controls which tools are available.

Use it when building, testing, or changing mcproxy, especially its TypeScript source, configuration files, proxy behavior, or documentation.

It gives contributors the project’s commands, file layout, architecture, and naming rules in one place.

How team-attention/mcproxy configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to team-attention/mcproxy. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/team-attention/mcproxy/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/team-attention/mcproxy

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/team-attention/mcproxy/claude-md/github.svg)](https://agentmods.dev/instructions/team-attention/mcproxy/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/team-attention/mcproxy/claude-md"><img src="https://agentmods.dev/badge/instructions/team-attention/mcproxy/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/team-attention/mcproxy/claude-md"><img src="https://agentmods.dev/badge/instructions/team-attention/mcproxy/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 384 This file is loaded in full into every session.

When invoked 384 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00384	$0.00384
Opus 5.5	$0.00154	$0.00154
Sonnet 5.5	$0.00077	$0.00077
Haiku 4.5	$0.00038	$0.00038

Measured 2mo ago against content hash 7f09b45990d7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcproxy 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 2mo 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.

CLAUDE.md · 41 lines

What it actually says

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

MCP Proxy for Claude Code - intercepts MCP server requests and filters tools based on .mcproxy.json configuration. Allows users to enable/disable specific MCP tools to reduce token consumption.

Commands

npm run build      # Compile TypeScript to dist/
npm test           # Run tests in watch mode
npm test -- --run  # Run tests once
npm run dev        # Run with tsx (development)

Architecture

Message Flow:

Claude Code ←→ mcproxy (stdio) ←→ MCP Server (subprocess)
                  ↓
            .mcproxy.json (tool config)

Key Modules:

src/index.ts - CLI entry point using Commander
src/proxy/mcp-proxy.ts - Main proxy class, manages upstream subprocess and stdio streams
src/proxy/message-handler.ts - Intercepts tools/list (filters response) and tools/call (blocks disabled tools)
src/config/config-manager.ts - Manages .mcproxy.json file, auto-registers new tools with enabled: true
src/config/mcp-config-reader.ts - Reads .mcp.json to auto-detect server name for config keys
src/filter/tool-filter.ts - Simple filter logic using ConfigManager

Server Name Resolution: The proxy reads .mcp.json to find which server name (e.g., "linear", "github") matches the current upstream command, then uses that as the key in .mcproxy.json.

File Naming

Use kebab-case for all TypeScript files (e.g., mcp-proxy.ts, config-manager.ts).

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.

2mo ago First seen · 41 lines · 384 tokens per session scan A 7f09b45990d7

Subscribe to this mod's changes

mcproxy CLAUDE.md is an instructions file published in the GitHub repository team-attention/mcproxy (19 stars, last pushed 10mo ago), licensed MIT. It adds 384 tokens to every session, about $0.0015 per session on Opus 5.5. 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.

mcproxy CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
mcproxy CLAUDE.mdteam-attention/mcproxy	Instructions file	19	10mo ago	MIT	A	384	Claude Code
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vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	3,093	GitHub Copilot
vscode model-prompts.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	2,022	GitHub Copilot

mcproxy: Instructions file for Claude Code