QWED MCP: Model Context Protocol security and verification

Model Context Protocol (MCP) Server for QWED Verification PyPI version

QWED-MCP brings deterministic verification to Claude Desktop, VS Code, and any MCP-compatible AI assistant. Instead of trusting LLMs to compute correctly, QWED-MCP provides a sandboxed Python execution environment with access to all QWED SDK verification libraries. Use QWED-MCP when you need MCP security, tool call verification, skill supply chain protection, and deterministic enforcement around Model Context Protocol actions.

Why QWED-MCP?

The problem

LLMs are unreliable for:

Mathematical calculations - They approximate, don’t compute
Logical reasoning - They guess patterns, don’t prove
Code security - They miss edge cases, don’t analyze
SQL queries - They don’t validate, just generate

The solution

QWED-MCP exposes deterministic verification to AI assistants through a single execute_python_code tool. The LLM writes a Python script that imports the appropriate QWED SDK, and the MCP server runs it in a sandboxed subprocess.

Without QWED-MCP	With QWED-MCP
LLM-only math → ~95% correct	QWED-MCP executes Python via `qwed_new` math engine → 100% correct
LLM-only SQL → unverified for injection	Script uses `qwed_new` SQL analyzer → injection detected
LLM-only reasoning → unverified	Z3 solver executed via SDK → formally proven
LLM-only code → unverified for safety	AST check script executed → security checked

How it works

┌─────────────────────────────────────────────────────────────┐
│                    Your AI Application                       │
│  ┌─────────────────┐        ┌─────────────────────────────┐ │
│  │  Claude Desktop │        │        VS Code + Copilot    │ │
│  │  or any MCP     │        │        or any MCP Client    │ │
│  │  compatible     │        │                             │ │
│  └────────┬────────┘        └──────────────┬──────────────┘ │
└───────────┼─────────────────────────────────┼───────────────┘
            │                                 │
            │         MCP Protocol            │
            │       (JSON-RPC over stdio)     │
            ▼                                 ▼
┌──────────────────────────────────────────────────────────────┐
│                     QWED-MCP Server (v0.2.0)                 │
├──────────────────────────────────────────────────────────────┤
│                                                              │
│  ┌────────────────────────────────────────────────────────┐  │
│  │          RiskBasedExecutionGateway                     │  │
│  │  └─► Policy lookup → Argument validation →            │  │
│  │      Code safety (AST) → Admin policy enforcement     │  │
│  ├────────────────────────────────────────────────────────┤  │
│  │              execute_python_code                       │  │
│  │  ├─► Synchronous Execution (30s timeout)               │  │
│  │  └─► Background Execution (background=true)            │  │
│  │       └─► Async Job Queue (up to 5 concurrent)         │  │
│  │           └─► Native QWED library execution            │  │
│  │               ├── qwed_new (math, logic, code, SQL)    │  │
│  │               ├── qwed_legal (deadlines, citations,..) │  │
│  │               ├── qwed_finance (banking, ISO 20022)    │  │
│  │               └── qwed_ucp (commerce verification)     │  │
│  ├────────────────────────────────────────────────────────┤  │
│  │              verification_status                       │  │
│  │  └─► Poll background job results by job_id             │  │
│  └────────────────────────────────────────────────────────┘  │
│                                                              │
└──────────────────────────────────────────────────────────────┘

Available tools

Tool	Description	Use case
`execute_python_code`	Subprocess execution	The primary entry point for all QWED capabilities. Executes dynamically generated Python code with access to all QWED SDK libraries. Supports optional `background=true` for async execution.
`verification_status`	Job status polling	Check the status and results of background verification jobs dispatched via `execute_python_code` with `background=true`.

All tool calls pass through the RiskBasedExecutionGateway before dispatch. The gateway validates arguments, runs code safety analysis, and enforces admin policy. The gateway blocks unknown tools by default.

In v0.1.x, QWED-MCP exposed individual tools like verify_math, verify_logic, verify_code, and verify_sql. These were consolidated into execute_python_code in v0.2.0 to solve context bloat (RFC-9728 compatibility). See migration guide.

Installation

From PyPI (recommended)

pip install qwed-mcp

From source

git clone https://github.com/QWED-AI/qwed-mcp.git
cd qwed-mcp
pip install -e .

Verify installation

qwed-mcp --version
# qwed-mcp 0.2.0

Quick start

Claude Desktop setup

Find your config file:
- Windows: %APPDATA%\Claude\claude_desktop_config.json
- macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
- Linux: ~/.config/Claude/claude_desktop_config.json
Add QWED-MCP server:

{
  "mcpServers": {
    "qwed-verification": {
      "command": "qwed-mcp",
      "env": {
        "QWED_MCP_TRUSTED_CODE_EXECUTION": "true"
      }
    }
  }
}

Restart Claude Desktop
Test it! Ask Claude:
“Write a Python script that verifies a $10,000 investment at 7.5% for 5 years using the compound interest formula, and run it using execute_python_code.”

VS Code setup

Install MCP extension (if not already)
Add to settings.json:

{
  "mcp.servers": {
    "qwed-verification": {
      "command": "qwed-mcp",
      "env": {
        "QWED_MCP_TRUSTED_CODE_EXECUTION": "true"
      }
    }
  }
}

Restart VS Code

Python client

You can also use QWED-MCP programmatically:

import asyncio
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client

async def main():
    server_params = StdioServerParameters(
        command="qwed-mcp",
        env={"QWED_MCP_TRUSTED_CODE_EXECUTION": "true"}
    )
    
    async with stdio_client(server_params) as (read, write):
        async with ClientSession(read, write) as session:
            await session.initialize()
            
            # List available tools
            tools = await session.list_tools()
            print(f"Available tools: {[t.name for t in tools.tools]}")
            # Output: Available tools: ['execute_python_code', 'verification_status']
            
            # Run a verification script
            result = await session.call_tool(
                "execute_python_code",
                arguments={
                    "code": (
                        "from sympy import symbols, diff\n"
                        "x = symbols('x')\n"
                        "print(f'd/dx(x^3) = {diff(x**3, x)}')"
                    )
                }
            )
            print(result)

asyncio.run(main())

Configuration

Environment variables

Variable	Description	Default
`QWED_MCP_TRUSTED_CODE_EXECUTION`	Enable `execute_python_code` tool (`true`/`false`)	`false`
`QWED_LOG_LEVEL`	Logging level (`DEBUG`, `INFO`, `WARNING`, `ERROR`)	`INFO`
`QWED_TIMEOUT`	Synchronous tool execution timeout in seconds	`30`
`QWED_MCP_BACKGROUND_TIMEOUT`	Background worker timeout in seconds for jobs dispatched with `background=true`. Clamped to a hard ceiling of `600`. Non-numeric or non-positive values fall back to the default	`120`
`QWED_SKILL_MANIFEST`	Path to a skill manifest JSON file. When set, the server validates the manifest at startup using `SkillProvenanceGuard` and refuses to start if verification fails	Not set

Set QWED_MCP_TRUSTED_CODE_EXECUTION to true to enable code execution. The executed code runs with server privileges — ensure inputs are from trusted sources.

Example with environment variables

Windows (PowerShell):

$env:QWED_MCP_TRUSTED_CODE_EXECUTION = "true"
$env:QWED_LOG_LEVEL = "DEBUG"
qwed-mcp

macOS/Linux:

QWED_MCP_TRUSTED_CODE_EXECUTION=true QWED_LOG_LEVEL=DEBUG qwed-mcp

Use cases

1. Financial calculations

Verify that AI-generated financial calculations are correct:

User: Calculate compound interest for $10,000 at 5% for 3 years

Claude: Let me verify this calculation.
        [Calls execute_python_code with a script using Decimal math]
        
        STDOUT: Future value = $11576.25
        ✅ Verified using deterministic decimal arithmetic.

2. Research validation

Ensure scientific claims are logically valid:

User: If all mammals are warm-blooded, and dolphins are mammals,
      are dolphins warm-blooded?

Claude: [Calls execute_python_code with a Z3 solver script]
        
        STDOUT: The conclusion logically follows from the premises.
        ✅ Verified via Z3 SMT solver.

3. Secure coding

Check AI-generated code for security issues:

User: Write a function to execute user commands

Claude: def run_command(cmd):
            os.system(cmd)
        
        [Calls execute_python_code with a CodeGuard script]
        
        STDOUT: Verified: False
          - Dangerous pattern: os.system
        
        ⚠️ Security issue detected. Here's a safer alternative...

4. SQL security

Prevent SQL injection in generated queries:

User: Generate a query to find user "admin' OR '1'='1"

Claude: [Calls execute_python_code with a SQLGuard script]
        
        STDOUT: Verified: False
          - SQL injection pattern detected
        
        ❌ Injection detected. Use parameterized queries instead.

MCP Server

Open Responses

UCP (Commerce)

QWED MCP: Model Context Protocol security and verification

Why QWED-MCP?

The problem

The solution

How it works

Available tools

Installation

From PyPI (recommended)

From source

Verify installation

Quick start

Claude Desktop setup

VS Code setup

Python client

Configuration

Environment variables

Example with environment variables

Use cases

1. Financial calculations

2. Research validation

3. Secure coding

4. SQL security

Links

MCP Server

Open Responses

UCP (Commerce)

Documentation Index

​Why QWED-MCP?

​The problem

​The solution

​How it works

​Available tools

​Installation

​From PyPI (recommended)

​From source

​Verify installation

​Quick start

​Claude Desktop setup

​VS Code setup

​Python client

​Configuration

​Environment variables

​Example with environment variables

​Use cases

​1. Financial calculations

​2. Research validation

​3. Secure coding

​4. SQL security

​Links

Why QWED-MCP?

The problem

The solution

How it works

Available tools

Installation

From PyPI (recommended)

From source

Verify installation

Quick start

Claude Desktop setup

VS Code setup

Python client

Configuration

Environment variables

Example with environment variables

Use cases

1. Financial calculations

2. Research validation

3. Secure coding

4. SQL security

Links