Pincer

Name: Pincer
Author: VouchlyAI

by VouchlyAIversion 0.1.5i★ –iRuns on your computer

Registry nameio.github.VouchlyAI/pincer

Install

Overview

Description from the maker (original English)

Secure grip for your agent's secrets - security-hardened MCP gateway with proxy token architecture

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Cybersecurity
You need to fill in: PINCER_PROXY_TOKEN

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: PINCER_PROXY_TOKEN, OPENWEBUI_URL, OPENAI_COMPATIBLE_URL, AUDIT_LOG_PATH

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "pincer": {
      "command": "npx",
      "args": [
        "-y",
        "pincer-mcp"
      ],
      "env": {
        "PINCER_PROXY_TOKEN": "your-value",
        "OPENWEBUI_URL": "your-value",
        "OPENAI_COMPATIBLE_URL": "your-value",
        "AUDIT_LOG_PATH": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add pincer --env PINCER_PROXY_TOKEN=your-value --env OPENWEBUI_URL=your-value --env OPENAI_COMPATIBLE_URL=your-value --env AUDIT_LOG_PATH=your-value -- npx -y pincer-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "pincer": {
      "command": "npx",
      "args": [
        "-y",
        "pincer-mcp"
      ],
      "env": {
        "PINCER_PROXY_TOKEN": "your-value",
        "OPENWEBUI_URL": "your-value",
        "OPENAI_COMPATIBLE_URL": "your-value",
        "AUDIT_LOG_PATH": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "pincer": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "pincer-mcp"
      ],
      "env": {
        "PINCER_PROXY_TOKEN": "your-value",
        "OPENWEBUI_URL": "your-value",
        "OPENAI_COMPATIBLE_URL": "your-value",
        "AUDIT_LOG_PATH": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

PINCER_PROXY_TOKEN secret required env
Proxy token for agent authentication (generated via 'pincer agent add')
OPENWEBUI_URL env
Optional: Base URL for OpenWebUI instance
OPENAI_COMPATIBLE_URL env
Optional: Base URL for OpenAI-compatible instance
AUDIT_LOG_PATH env
Optional: Custom path for audit logs (default: ~/.pincer/audit.jsonl)

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 8, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account VouchlyAI, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Cybersecurityi

More stars than 0% of the other 995 servers in this category
Published to the registry more recently than 3% of the other 995 servers in this category
Basic checks equal to or better than 100% of the other 995 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Pincer safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: PINCER_PROXY_TOKEN

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.5) reached the registry 9 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: WatchGuard MCP, ipdata MCP by usefulapi, MaxMind minFraud MCP by usefulapi

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Pincer MCP 🦀

Pincer-MCP is a security-hardened Model Context Protocol (MCP) gateway that eliminates the "Lethal Trifecta" vulnerability in agentic AI systems. By acting as a stateless intermediary, Pincer ensures agents never see your real API keys.

🔒 The Problem

Current AI agents store long-lived API keys in plain-text .env files or local databases. If compromised via prompt injection or host intrusion, attackers gain direct access to your:

Database passwords
Third-party API keys

✨ The Solution: Proxy Token Architecture

Pincer implements a "blindfold" security model:

Agent knows: Only a unique proxy token (pxr_abc123...)
Pincer knows: Mapping of proxy tokens → real API keys (encrypted in OS keychain)
Agent never sees: The actual credentials

sequenceDiagram

participant Agent participant Pincer participant Vault (OS Keychain) participant External API

Agent->>Pincer: tools/call + proxy_token: pxr_abc123 Pincer->>Vault: Decrypt real API key Vault-->>Pincer: gemini_api_key: AIzaSy... Pincer->>External API: API call with real key External API-->>Pincer: Response Pincer->>Pincer: Scrub key from memory Pincer-->>Agent: Response (no credentials)

## 📦 Available Tools

gemini_generate: Secure Google Gemini API calls.
openai_chat: Chat completions with OpenAI GPT models (gpt-4o, gpt-4-turbo, gpt-3.5-turbo, etc.).
openai_list_models: List all available OpenAI models.
openai_compatible_chat: Chat completions with any OpenAI-compatible API (Azure OpenAI, Ollama, vLLM, etc.).
openai_compatible_list_models: List models from custom OpenAI-compatible endpoints.
claude_chat: Chat completions with Anthropic Claude models (Claude 3.5 Sonnet, Opus, Haiku).
openrouter_chat: Unified API access to 100+ models from multiple providers (OpenAI, Anthropic, Google, Meta, etc.).
openrouter_list_models: List all available models across OpenRouter providers.
openwebui_chat: OpenAI-compatible interface for self-hosted LLMs.
openwebui_list_models: Discover available models on an OpenWebUI instance.
gpg_sign_data: Sign data or files using a GPG/PGP private key stored in Pincer's vault. *(Keyless Execution — agent never sees the key)*
gpg_decrypt: Decrypt PGP-encrypted data using a vault-stored private key.

🔑 GPG Key Management

# Generate a new GPG keypair (private key stored in vault)

pincer key generate --name "Release Signing" --email dev@example.com

Import an existing PGP private key

pincer key import ./my-key.asc --passphrase "my-passphrase"

List all stored GPG keys

pincer key list

Export public key (safe to share)

pincer key export

Authorize an agent for signing

pincer agent authorize mybot gpg_sign_data --key

*(More callers coming soon!)*

🚀 Quick Start

Prerequisites

Node.js 18+
macOS, Windows, or Linux with native keychain support

Installation

Option 1: Global Installation (Recommended)

npm install -g pincer-mcp

Now 'pincer' command is available system-wide

Option 2: Local Development

git clone https://github.com/VouchlyAI/Pincer-MCP.git

cd Pincer-MCP npm install npm run build npm link # Makes 'pincer' command available locally

Setup Vault

# 1. Initialize vault (creates master key in OS keychain)

pincer init

2. Store your real API keys (encrypted)

pincer set gemini_api_key "AIzaSyDpxPq..." pincer set openai_api_key "sk-proj-..."

3. Register an agent and generate proxy token

pincer agent add openclaw

Output: 🎫 Proxy Token: pxr_V1StGXR8_Z5jdHi6B-myT

4. Authorize the agent for specific tools

pincer agent authorize openclaw gemini_generate

Multi-Key Support

Store multiple keys for the same tool and assign them to different agents:

# Store two different Gemini API keys

pincer set gemini_api_key "AIzaSy_KEY_FOR_CLAWDBOT..." --label key1 pincer set gemini_api_key "AIzaSy_KEY_FOR_MYBOT..." --label key2

View all stored keys

pincer list

Assign specific keys to each agent

pincer agent add clawdbot pincer agent authorize clawdbot gemini_generate --key key1

pincer agent add mybot pincer agent authorize mybot gemini_generate --key key2

View agent permissions

pincer agent list

Result: clawdbot uses key1, mybot uses key2 - perfect for rate limiting or cost tracking!

Run the Server

npm run dev

Configure Your Agent

Give your agent the proxy token (not the real API key):

export PINCER_PROXY_TOKEN="pxr_V1StGXR8_Z5jdHi6B-myT"

Tool-to-Secret Name Mappings

When storing secrets, you must use the correct secret name for each tool. See the [Tool Mappings Guide](docs/TOOL_MAPPINGS.md) for a complete reference.

When you run pincer agent authorize myagent gemini_generate, Pincer will inject the gemini_api_key secret when that tool is called.

Make a Tool Call

Your agent sends requests with the proxy token in the body:

"jsonrpc": "2.0", "method": "tools/call", "params": { "name": "gemini_generate", "arguments": { "prompt": "Hello world", "model": "gemini-2.0-flash" }, "_meta": { "pincer_token": "pxr_V1StGXR8_Z5jdHi6B-myT" } } }

Pincer maps the proxy token to the real API key and executes the call securely.

🏗️ Architecture

Two-Tiered Vault System

Tier 1: Master Key (OS Keychain)

Stored in macOS Keychain, Windows Credential Manager, or GNOME Keyring
Never touches the filesystem
Accessed only for encryption/decryption

Tier 2: Encrypted Store (SQLite)

Database at ~/.pincer/vault.db
Three tables:
secrets: Real API keys (AES-256-GCM encrypted)
proxy_tokens: Proxy token → Agent ID mappings
agent_mappings: Agent ID → Tool authorization

Authentication Flow

Request (_meta.pincer_token: pxr_xxx)

↓ Gatekeeper: Extract proxy token from body ↓ Vault: Resolve pxr_xxx → agent_id → tool_name → real_api_key ↓ Injector: JIT decrypt & inject real key ↓ Caller: Execute external API call ↓ Scrubber: Overwrite key in memory with zeros ↓ Audit: Log to tamper-evident chain

🔐 Security & Compliance

Pincer is built for enterprise-grade security:

Hardware-Backed Cryptography: Master encryption keys never leave the OS-native keychain.
Proxy Token Isolation: Agents only handle ephemeral pxr_ tokens; they never touch real credentials.
JIT Decryption: Secrets are decrypted only for the duration of the API call.
Zero-Footprint Memory: Sensitive data is scrubbed (zeroed out) from memory immediately after use.
Fine-Grained Authorization: Strict per-agent, per-tool access control policies.
Tamper-Evident Audit Log: Append-only tool call history with SHA-256 chain-hashing.
Hardened Execution: Schema validation on all inputs and protected environment execution.
Stdio Compatible: Fully compatible with the standard Model Context Protocol transport.

🔍 Audit Logs

Every tool call is logged to ~/.pincer/audit.jsonl with both UTC and Local timestamps, plus character counts and estimated token usage:

"agentId": "openclaw", "tool": "gemini_generate", "duration": 234, "status": "success", "input_chars": 156, "output_chars": 423, "estimated_input_tokens": 39, "estimated_output_tokens": 106, "timestamp_utc": "2026-02-05T08:32:00.000Z", "timestamp_local": "2/5/2026, 2:02:45 PM", "chainHash": "a1b2c3d4e5f6g7h8", "prevHash": "0000000000000000" }

Token Estimation: Pincer automatically estimates token usage using a 4:1 character-to-token ratio (~4 characters per token average). This provides consistent cost tracking across all AI providers without relying on provider-specific APIs.

Chain hashes provide tamper detection - any modification breaks the SHA-256 chain.

🧪 Development

# Install dependencies

npm install

Run tests

npm test

Run with watch mode

npm run dev

Build for production

npm run build

📚 Documentation

[Setup Guide](docs/SETUP.md) - Getting started with Pincer-MCP
[IDE Integration](docs/IDE_INTEGRATION.md) - Use Pincer with VSCode, Claude Desktop, Cursor, and more
[OpenClaw Integration](docs/OPENCLAW_INTEGRATION.md) - Integrate Pincer with OpenClaw agents
[Testing Guide](docs/TESTING.md) - Comprehensive test suite documentation
[Capabilities Reference](docs/CAPABILITIES.md) - Full API and feature documentation
[Security Policy](SECURITY.md) - Vulnerability reporting and security best practices
[CHANGELOG](CHANGELOG.md) - Version history and release notes

🤝 Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

📄 License

BSL 1.1 (Business Source License) — See LICENSE for details. Converts to Apache 2.0 on 2028-04-01.

Model Context Protocol - The standard for AI tool integration.
keytar - Secure cross-platform keychain access.
better-sqlite3 - High-performance local persistence.

Built with ❤️ for a more secure AI future.

Pincer

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Cybersecurityi

Common questions

Alternatives

WatchGuard MCP

ipdata MCP by usefulapi

MaxMind minFraud MCP by usefulapi

README from the maker

Pincer MCP 🦀

🔒 The Problem

✨ The Solution: Proxy Token Architecture

🔑 GPG Key Management

Import an existing PGP private key

List all stored GPG keys

Export public key (safe to share)

Authorize an agent for signing

🚀 Quick Start

Prerequisites

Installation

Now 'pincer' command is available system-wide

Setup Vault

2. Store your real API keys (encrypted)

3. Register an agent and generate proxy token

Output: 🎫 Proxy Token: pxr_V1StGXR8_Z5jdHi6B-myT

4. Authorize the agent for specific tools

Multi-Key Support

View all stored keys

Assign specific keys to each agent

View agent permissions

Run the Server

Configure Your Agent

Tool-to-Secret Name Mappings

Make a Tool Call

🏗️ Architecture

Two-Tiered Vault System

Authentication Flow

🔐 Security & Compliance

🔍 Audit Logs

🧪 Development

Run tests

Run with watch mode

Build for production

📚 Documentation

🤝 Contributing

📄 License