MCP Monitor

Transparent observability for agentic AI pipelines.

MCP Monitor intercepts every tool call made by an AI agent — whether the agent uses the Model Context Protocol (MCP) or calls Python functions directly — and surfaces metrics, session replays, and alerts through a local web dashboard.

Zero changes to your agent. Zero changes to your MCP servers.

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Features

• ⚡ Live Feed — Real-time SSE-powered stream of all tool calls with status badges and latency
• 📋 Session Replay — Browse sessions, view call timelines with a Gantt chart, expand any call to inspect arguments and responses
• 📊 Tool Analytics — P50/P95/P99 latency charts, call volume, and error rate trends via Chart.js
• 🖥️ Server Health — Per-server status cards (healthy / degraded / down) with auto-refresh
• 🔔 Alerts — Configurable P95 latency and error rate thresholds with cooldown-based alerting
• 🔒 Secret Sanitization — Automatically redacts tokens, passwords, API keys from stored arguments
• 🐍 Python SDK — Zero-dependency pip package to monitor any Python agent (QwenAgent, LangChain, custom)
• 💾 SQLite Storage — Single-file database with WAL mode for fast concurrent reads

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Architecture

Agent (Claude, Cursor, etc.)
    │
    ├── Multiplexer mode
    │     mcp-monitor serve
    │       ├── spawns Server A ──┐
    │       ├── spawns Server B ──┤── POST /api/ingest ──► Dashboard Server ──► SQLite
    │       └── spawns Server C ──┘         │
    │                                  EventBus.emit()
    ├── Per-server proxy mode                │
    │     mcp-monitor proxy             SSE push to
    │       └── spawns Server ──────►   Dashboard UI
    │
    └── Python SDK ──► POST /api/ingest

Multiplexer mode is the one approach: add one entry to your MCP config and monitor all servers. The serve command spawns every configured server, merges their tools, routes calls, and records everything.

Per-server proxy mode wraps a single server — useful when you want fine-grained control over which servers are monitored.

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Quick Start

Prerequisites

• Node.js 18+
• npm

Install via GitHub Packages

1. Authenticate to GitHub Packages: You need a Personal Access Token (classic) with the read:packages scope.
2. Tell npm where to find the package:

   echo "@partha-sust16:registry=https://npm.pkg.github.com" >> ~/.npmrc
   

3. Install the package globally:

   npm install -g @partha-sust16/mcp-monitor
   

You are now ready to run mcp-monitor start!

Install from Source

git clone https://github.com/Partha-SUST16/mcp_monitor.git
cd mcp_monitor

# Install backend dependencies
npm install

# Build the backend and the dashboard UI automatically
npm run build

# Link globally to use the 'mcp-monitor' command anywhere
npm link

# Start the dashboard server
mcp-monitor start

The dashboard will be available at http://localhost:4242.

Send a Test Event

curl -X POST http://localhost:4242/api/ingest \
  -H 'Content-Type: application/json' \
  -d '{
    "sessionId": "test-session",
    "agentType": "python-sdk",
    "serverName": "my-server",
    "toolName": "read_file",
    "method": "read_file",
    "arguments": {"path": "/tmp/test.txt"},
    "response": null,
    "status": "success",
    "latencyMs": 150,
    "timestamp": "2026-03-09T10:00:00Z"
  }'

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Connecting Agents

Multiplexer Mode

Monitor all MCP servers with a single config entry. No need to wrap each server individually.

Step 1. List your servers in mcp-monitor.config.json:

{
  "servers": [
    { "name": "filesystem", "transport": "stdio", "command": "npx @modelcontextprotocol/server-filesystem /tmp" },
    { "name": "github", "transport": "stdio", "command": "npx @modelcontextprotocol/server-github", "env": { "GITHUB_TOKEN": "$GITHUB_TOKEN" } }
  ],
  "dashboard": { "port": 4242 }
}

Step 2. Replace all MCP server entries in your agent config with one:

{
  "mcpServers": {
    "mcp-monitor": {
      "command": "mcp-monitor",
      "args": ["serve", "-c", "/absolute/path/to/mcp-monitor.config.json"]
    }
  }
}

Step 3. Start the dashboard server separately:

mcp-monitor start

The agent sees one MCP server with all tools combined. MCP Monitor spawns each real server internally, routes every tools/call to the correct child, and records the call.

Note on Tool Names: To prevent naming collisions between different MCP servers that happen to expose identical tools, the Multiplexer prefixes all tool names with their originating server's name. For example, if your filesystem server has a tool named read_file, the LLM will see it exposed as filesystem_read_file.

Per-Server Proxy Mode

Alternatively, wrap individual servers by replacing their command:

{
  "mcpServers": {
    "filesystem": {
      "command": "mcp-monitor",
      "args": ["proxy", "--name", "filesystem",
               "--cmd", "npx @modelcontextprotocol/server-filesystem /tmp"]
    }
  }
}

Python Agent (QwenAgent)

from agent_monitor import patch_qwen_agent

patch_qwen_agent(server_name="my-agent")  # call once before creating agent
# rest of agent code unchanged

Generic Python Tool

from agent_monitor import monitor

@monitor(server_name="my-tools")
def query_database(sql: str) -> dict:
    ...

Python SDK Installation

cd sdk/python
pip install -e .

The SDK has zero external dependencies — it uses only Python stdlib (urllib, threading, json).

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Configuration

Create mcp-monitor.config.json in the project root:

{
  "servers": [
    {
      "name": "filesystem",
      "transport": "stdio",
      "command": "npx @modelcontextprotocol/server-filesystem /tmp"
    },
    {
      "name": "github",
      "transport": "stdio",
      "command": "npx @modelcontextprotocol/server-github",
      "env": { "GITHUB_TOKEN": "$GITHUB_TOKEN" }
    },
    {
      "name": "remote-tools",
      "transport": "http",
      "targetUrl": "https://my-mcp-server.com",
      "listenPort": 4243
    }
  ],
  "dashboard": {
    "port": 4242
  },
  "alerts": {
    "latencyP95Ms": 2000,
    "errorRatePercent": 10,
    "cooldownMinutes": 5
  }
}

Environment variable substitution is supported in env fields — $VAR_NAME is replaced with process.env.VAR_NAME.

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CLI Commands

# Start dashboard server + alert engine
mcp-monitor start [-c path/to/config.json]

# Run as a multiplexing MCP server (add as single entry in agent config)
mcp-monitor serve [-c path/to/config.json] [--dashboard-url http://localhost:4242]

# Start a single MCP proxy (wrap one server)
mcp-monitor proxy --name filesystem --cmd "npx @modelcontextprotocol/server-filesystem /tmp"

# List recent sessions
mcp-monitor sessions [--limit 20]

# Replay a session's tool calls
mcp-monitor replay <session-id>

# Show per-tool stats
mcp-monitor stats [--sort latency_p95|error_rate|call_count] [--since 1h|6h|24h|7d]

# Export data
mcp-monitor export [--format json|csv] [--since 24h] [--output file.json]

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REST API

Endpoint	Description
GET /api/overview	Aggregated stats: total calls, error rate, avg/p95 latency, recent calls
GET /api/sessions	Paginated session list with call counts (?limit=20&offset=0)
GET /api/sessions/:id/calls	All tool calls for a session in chronological order
GET /api/tools/stats	Per-tool latency percentiles and error rates (?since=24h)
GET /api/servers	Server health status derived from last 5 minutes of data
GET /api/alerts	Fired alert history (?limit=50&offset=0)
GET /api/stream	SSE endpoint — pushes tool_call and alert events in real time
POST /api/ingest	Accepts CollectorEvent JSON (used by Python SDK)

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Project Structure

mcp-monitor/
├── src/
│   ├── types.ts                          # All shared TypeScript interfaces
│   ├── config.ts                         # Config loader with env var substitution
│   ├── cli.ts                            # Commander.js entry point
│   ├── core/
│   │   ├── Store.ts                      # SQLite (better-sqlite3) CRUD
│   │   ├── Collector.ts                  # Sanitize → truncate → persist → emit
│   │   ├── RemoteCollector.ts           # HTTP POST to dashboard /api/ingest
│   │   ├── SessionManager.ts            # Session lifecycle + idle timeout
│   │   ├── EventBus.ts                  # Node.js EventEmitter singleton
│   │   └── AlertEngine.ts              # P95 latency & error rate monitoring
│   ├── ingestion/
│   │   ├── mcp/
│   │   │   ├── MuxServer.ts             # Multiplexing MCP server (aggregates all servers)
│   │   │   ├── ProtocolInterceptor.ts   # JSON-RPC request/response matching
│   │   │   ├── StdioProxy.ts            # MCP stdio transport proxy
│   │   │   └── HttpProxy.ts            # MCP HTTP reverse proxy
│   │   └── IngestEndpoint.ts            # POST /api/ingest handler
│   └── dashboard/
│       ├── server.ts                     # Express + SSE + static serving
│       ├── routes/                       # API route handlers
│       └── ui/                           # React + Vite dashboard
│           └── src/pages/
│               ├── LiveFeed.tsx
│               ├── SessionReplay.tsx
│               ├── ToolAnalytics.tsx
│               ├── ServerHealth.tsx
│               └── Alerts.tsx
├── sdk/python/
│   ├── pyproject.toml
│   └── agent_monitor/
│       ├── __init__.py
│       ├── collector.py                  # Fire-and-forget POST to /api/ingest
│       └── decorators.py                # patch_qwen_agent() + @monitor
├── mcp-monitor.config.json
├── package.json
└── tsconfig.json

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Tech Stack

Layer	Technology
MCP Proxy	TypeScript (child_process, JSON-RPC parsing)
Core	TypeScript + Express 5
Database	SQLite via better-sqlite3 (WAL mode)
Dashboard UI	React 19 + Vite + Chart.js
Real-time Push	Server-Sent Events (SSE)
Python SDK	Python 3.9+ (stdlib only)
CLI	Commander.js

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Session Management

Sessions are created and managed automatically:

• MCP connections: A new session starts on every initialize JSON-RPC message
• Idle timeout: If 5+ minutes pass between tool calls, a new session is created
• Explicit session ID: Set MCP_MONITOR_SESSION_ID env var for deterministic session grouping
• Python SDK: Each Python process gets a unique UUID session, or set AGENT_MONITOR_SESSION_ID
• Session end: Marked when the proxied process exits or the connection closes

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Alert System

The AlertEngine is fully event-driven — no polling. It listens to every tool_call event from the EventBus and evaluates thresholds in real time:

• P95 Latency per tool → fires if above latencyP95Ms threshold
• Error Rate per tool → fires if above errorRatePercent threshold (requires ≥5 calls)

Cooldown logic prevents the same alert from re-firing within cooldownMinutes (default: 5 min). Alerts are persisted to SQLite and pushed to the dashboard via SSE.

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License

MIT