QMCP - Model Context Protocol Server

A spec-aligned Model Context Protocol (MCP) server built with FastAPI.

Features

• ✅ Tool Discovery - List available tools via /v1/tools
• ✅ Tool Invocation - Execute tools via /v1/tools/{name}
• ✅ Invocation History - Audit trail via /v1/invocations
• ✅ Human-in-the-Loop - Request human input via /v1/human/*
• ✅ Persistence - SQLite with SQLModel/aiosqlite
• ✅ Python Client - qmcp.client.MCPClient for workflows
• ✅ Metaflow Examples - Ready-to-use flow templates
• ✅ Agent Framework - SQLModel schemas + mixins for agent types/topologies
• ✅ Structured Logging - JSON logs with structlog
• ✅ Request Tracing - Correlation IDs across requests
• ✅ Metrics - Prometheus-compatible /metrics endpoint
• ✅ CLI Interface - Manage via qmcp command

Quick Start

# Install dependencies
uv sync

# Start the server
uv run qmcp serve

# Or with development reload
uv run qmcp serve --reload

See quickstart.md for a copy-paste walkthrough.

Adoption and Onboarding

Adoption checklist:

• Decide how the server is hosted (local, container, or VM) and who can reach it.
• Set QMCP_HOST, QMCP_PORT, and QMCP_DATABASE_URL for your environment.
• Standardize X-Correlation-ID values for audit trails across clients.
• Decide how humans submit HITL responses (UI or API).
• Wire /metrics into your monitoring stack.

Onboarding path:

1. uv sync --all-extras
2. Run the end-to-end tutorial below.
3. uv run qmcp serve for local exploration.

End-to-End Tutorial (HITL approval workflow)

This tutorial mirrors the end-to-end test tests/test_hitl.py::TestHITLWorkflow::test_complete_approval_workflow.

Copy and paste:

uv sync --all-extras
uv run pytest tests/test_hitl.py::TestHITLWorkflow::test_complete_approval_workflow -v

Client Library

from qmcp.client import MCPClient

with MCPClient(base_url="http://localhost:3333") as client:
    # List tools
    tools = client.list_tools()

    # Invoke a tool
    result = client.invoke_tool("echo", {"message": "Hello!"})
    print(result.result)

    # Human-in-the-loop
    request = client.create_human_request(
        request_id="approval-001",
        request_type="approval",
        prompt="Approve deployment?",
        options=["approve", "reject"]
    )
    response = client.wait_for_response("approval-001", timeout=3600)

See docs/client.md for full API documentation.

CLI Commands

# Start the server
qmcp serve [--host HOST] [--port PORT] [--reload]

# List registered tools
qmcp tools list

# Show configuration
qmcp info

# Run tests with auto setup/teardown
qmcp test [-v] [--coverage] [TEST_PATH]

API Endpoints

Endpoint	Method	Description
/health	GET	Health check
/v1/tools	GET	List available tools
/v1/tools/{name}	POST	Invoke a tool
/v1/invocations	GET	List invocation history
/v1/invocations/{id}	GET	Get single invocation
/v1/human/requests	POST	Create human request
/v1/human/requests	GET	List human requests
/v1/human/requests/{id}	GET	Get request with response
/v1/human/responses	POST	Submit human response
/metrics	GET	Prometheus metrics
/metrics/json	GET	Metrics as JSON

Built-in Tools

• echo - Echo input back (for testing)
• planner - Create execution plans
• executor - Execute approved plans
• reviewer - Review and assess results

Development

# Install dev dependencies
uv sync --all-extras

# Run tests (with auto cleanup)
uv run qmcp test -v

# Run tests with coverage
uv run qmcp test --coverage

# Run linter
uv run ruff check .

Architecture

See docs/architecture.md for the full architectural overview.

The system follows a three-plane architecture:

1. Client/Orchestration - Metaflow workflows (MCP client)
2. MCP Server - FastAPI service (this project)
3. Execution/Storage - Tools and database

Documentation

• Quickstart - Copy-paste setup and validation
• Overview - What and why
• Architecture - How and constraints
• Tools - Tool capabilities
• Client Library - Python client API
• Human-in-the-Loop - HITL guide
• Agent Framework - Agent schemas and mixins
• Deployment - Production deployment guide
• Contributing - Development guidelines
• Roadmap - Development phases

Example Flows

See examples/flows/ for Metaflow integration examples:

• simple_plan.py - Basic tool invocation
• approved_deploy.py - HITL approval workflow
• local_agent_chain.py - Local LLM plan -> review -> refine with SQLModel artifacts
• local_qc_gauntlet.py - Local LLM QC checklist/task/gate builder
• local_release_notes.py - Local LLM release notes and doc update suggestions

For local LLM flows, install extras with uv sync --extra flows. Start uv run qmcp serve when --use-mcp True to enable MCP calls. On Windows, prefer running flows in a Linux container to avoid platform-specific Metaflow dependencies.

Docker runner (recommended on Windows):

docker compose -f docker-compose.flows.yml build
docker compose -f docker-compose.flows.yml run --rm flow-runner \
  examples/flows/local_agent_chain.py run --use-mcp True --goal "..."

Set MCP_URL and LLM_BASE_URL (or pass --mcp-url / --llm-base-url) when running in Docker, e.g. http://host.docker.internal:3333.

License

MIT