Proms MCP Server

A lean MCP (Model Context Protocol) server that provides LLM agents with transparent access to multiple Prometheus instances for metrics analysis and SRE operations.

Overview

This server implements the MCP protocol using the modern FastMCP library, allowing LLM agents to query multiple Prometheus instances through a unified interface. It supports discovery, querying, and analysis of Prometheus metrics with built-in security validation and comprehensive observability.

Features

• Multiple Prometheus Support: Query multiple Prometheus instances through a single interface
• Bearer Token Authentication: Secure authentication using OpenShift bearer tokens
• Security Hardening: Basic PromQL query validation for safety
• Comprehensive Toolset: 8 MCP tools covering discovery, querying, and analysis using modern @tool decorators
• Observability: Structured logging for debugging and monitoring
• Production Ready: Designed for OpenShift/Kubernetes deployment
• Lean Architecture: Stateless, minimal dependencies (5 core dependencies), fail-fast design

MCP Tools

Discovery Tools

• list_datasources: List all available Prometheus datasources
• list_metrics: Get all available metric names from a datasource
• get_metric_metadata: Get metadata for a specific metric

Query Tools

• query_instant: Execute instant PromQL query
• query_range: Execute range PromQL query

Analysis Tools

• get_metric_labels: Get all label names for a specific metric
• get_label_values: Get all values for a specific label
• find_metrics_by_pattern: Find metrics matching a regex pattern

Quick Start

Prerequisites

• Python 3.11+
• uv for dependency management
• Docker/Podman for container development

Local Development

# Clone and setup
git clone <repository-url>
cd proms-mcp
make install

# 1. Login to your target cluster and get your token
oc login https://api.your-cluster.example.com:6443
export OPENSHIFT_TOKEN=$(oc whoami -t)

# 2. Create datasource config with your token
# this assumes your openshift token is valid to authenticate on prometheus
cat > local_config/datasources.yaml << EOF
datasources:
  - name: "my-prometheus"
    type: "prometheus"
    url: "https://prometheus.your-cluster.example.com"
    jsonData:
      httpHeaderName1: "Authorization"
    secureJsonData:
      httpHeaderValue1: "Bearer ${OPENSHIFT_TOKEN}"
EOF

# 3. Run the server with authentication enabled
make run-auth OPENSHIFT_API_URL=$(oc whoami --show-server)
# Or run the server without authentication - the connection to prometheus will still be authenticated
make run

# 4. Configure your MCP client (e.g. with Cursor and auth-enabled proms-mcp)
cat > .cursor/mcp.json << EOF
{
  "mcpServers": {
    "proms-mcp-local-auth": {
      "url": "http://localhost:8000/mcp/",
      "headers": {
        "Authorization": "Bearer ${OPENSHIFT_TOKEN}"
      }
    }
  }
}
EOF

Container Development

# Build container
podman build -t proms-mcp .

# Create datasource config (see Configuration section)
# Run with config
podman run -p 8000:8000 \
  -v ./datasources.yaml:/etc/grafana/provisioning/datasources/datasources.yaml:ro \
  proms-mcp

MCP Client Setup

Cursor Integration

The server supports two authentication modes:

Development (No Authentication):

{
  "mcpServers": {
    "proms-mcp-dev": {
              "url": "http://localhost:8000/mcp/",
      "description": "Development server - no authentication"
    }
  }
}

Production (Bearer Token Authentication):

{
  "mcpServers": {
    "proms-mcp": {
      "url": "https://proms-mcp.apps.cluster.example.com/mcp",
      "headers": {
        "Authorization": "Bearer your-openshift-token-here"
      },
      "description": "Production server with OpenShift bearer token auth"
    }
  }
}

⚠️ Security Note: Never commit .cursor/mcp.json with real tokens to git. It's already in .gitignore.

See .cursor/mcp-examples.json for complete configuration examples including:

• Development and production setups
• Service account token configuration
• Multi-environment configurations
• SSL verification scenarios

Other MCP Clients

The server exposes MCP over HTTP at:

• Endpoint: POST http://localhost:8000/mcp/ (or your deployed URL)
• Protocol: JSON-RPC 2.0 over HTTP
• Content-Type: application/json
• Accept: application/json, text/event-stream
• Authentication: Bearer token in Authorization header (when AUTH_MODE=active)

📝 Path Behavior: The server uses /mcp/ (with trailing slash) to avoid HTTP 307 redirects that can cause authentication issues in some MCP clients. Always use the trailing slash in your client configurations.

Configuration

Environment Variables

• PORT: MCP server port (default: 8000)
• HEALTH_METRICS_PORT: Health and metrics server port (default: 8080)
• LOG_LEVEL: Logging level (default: INFO)
• GRAFANA_DATASOURCES_PATH: Path to datasource config file (default: /etc/grafana/provisioning/datasources/datasources.yaml)
• QUERY_TIMEOUT: Query timeout in seconds (default: 30)

Authentication Configuration

The server supports two authentication modes:

• AUTH_MODE: Authentication mode (none or active, default: active)
• OPENSHIFT_API_URL: OpenShift API server URL (required for bearer token auth)
• OPENSHIFT_CA_CERT_PATH: Path to CA certificate file for SSL verification (optional, only needed for custom certificates)

No Authentication Mode (Development Only)

# Explicitly disable authentication for development
AUTH_MODE=none uv run python -m proms_mcp

Bearer Token Authentication Mode (Default)

# Run with bearer token authentication
AUTH_MODE=active \
OPENSHIFT_API_URL=https://api.cluster.example.com:6443 \
uv run python -m proms_mcp

# if you're authenticated on openshift already:
AUTH_MODE=active \
OPENSHIFT_API_URL=$(oc whoami --show-server) \
uv run python -m proms_mcp

# For self-signed certificates, you can provide the CA certificate (if needed for custom certificates):
OPENSHIFT_CA_CERT_PATH=/path/to/ca.crt uv run python -m proms_mcp

Authentication Implementation: The server uses Kubernetes TokenReview API with self-validation to authenticate OpenShift bearer tokens. Each user's token validates itself - no special RBAC permissions are needed. Authentication is handled by a custom TokenReviewVerifier that integrates with FastMCP's authentication system.

Datasource Configuration

Create a Grafana datasource provisioning YAML file. Only type: "prometheus" datasources are processed.

Example datasources.yaml:

apiVersion: 1
prune: true
datasources:
  - name: "prod-prometheus"
    type: "prometheus"
    url: "https://prometheus-prod.example.com"
    access: "proxy"
    editable: false
    jsonData:
      httpHeaderName1: "Authorization"
    secureJsonData:
      httpHeaderValue1: "Bearer prod-token"
  - name: "demo-prometheus"
    type: "prometheus"
    url: "https://demo.robustperception.io:9090"
    access: "proxy"
    editable: false

Security

PromQL Query Validation

The server implements basic security checks:

• Query Length: Limits to 10,000 characters
• Empty Query: Prevents empty or whitespace-only queries
• Input Sanitization: Basic parameter encoding via httpx

API Endpoints

• POST /mcp/: MCP JSON-RPC 2.0 endpoint (port 8000)
• GET /health: Health check (port 8080)
• GET /metrics: Prometheus metrics (port 8080)

Deployment

OpenShift Deployment

Deploy using the provided OpenShift template:

# Development deployment (no authentication)
oc process -f openshift/deploy.yaml \
  -p IMAGE=quay.io/app-sre/proms-mcp \
  -p IMAGE_TAG=latest \
  -p AUTH_MODE=none \
  | oc apply -f -

# Production deployment (bearer token authentication)
oc process -f openshift/deploy.yaml \
  -p IMAGE=quay.io/app-sre/proms-mcp \
  -p IMAGE_TAG=v1.0.0 \
  -p AUTH_MODE=active \
  -p OPENSHIFT_API_URL=https://api.cluster.example.com:6443 \
  | oc apply -f -

# No additional RBAC setup is needed - the server uses self-validation

Template Parameters:

• AUTH_MODE: none (development) or active (production, default)
• OPENSHIFT_API_URL: OpenShift API server URL (default: https://kubernetes.default.svc for in-cluster)
• OPENSHIFT_CA_CERT_PATH: CA certificate path (default: in-cluster service account CA)
• NAMESPACE: Target namespace (required)
• HOSTNAME: Route hostname (required)

MCP Client Configuration

Development Mode (No Authentication)

{
  "mcpServers": {
    "proms-mcp-dev": {
      "url": "http://localhost:8000/mcp"
    }
  }
}

Production Mode (Bearer Token)

{
  "mcpServers": {
    "proms-mcp": {
      "url": "https://proms-mcp.apps.cluster.example.com/mcp",
      "headers": {
        "Authorization": "Bearer ${OPENSHIFT_TOKEN}"
      }
    }
  }
}

Get your OpenShift token:

export OPENSHIFT_TOKEN=$(oc whoami -t)

RBAC Requirements

For production (bearer token authentication) deployments:

1. ServiceAccount: proms-mcp-server (created by template) - used only for pod identity
2. No special RBAC permissions needed: The server uses self-validation where each user's token validates itself
3. User Tokens: Users need valid OpenShift tokens (oc whoami -t)

The template creates the ServiceAccount for pod identity. No ClusterRoleBindings or special permissions are required because the authentication uses self-validation.

Development

Code Quality

make format          # Format code and fix imports
make lint            # Lint and type check code
make test            # Run tests with coverage

Project Structure

proms-mcp/
  proms_mcp/             # Main package
    auth.py                # TokenReview-based authentication with FastMCP integration
    server.py              # FastMCP server with 8 MCP tools
    client.py              # Prometheus API wrapper
    config.py              # Config parser with auth support
    monitoring.py          # Health/metrics endpoints  
    logging.py             # Structured logging configuration
  tests/                   # Test suite (mirrors package structure)
  openshift/deploy.yaml    # OpenShift template with RBAC support
  local_config/            # Local development configuration

Troubleshooting

Common Issues

1. No datasources loaded:
   • Check that GRAFANA_DATASOURCES_PATH points to your datasources file
   • Verify YAML syntax is valid (JSON format is also supported)
   • Ensure the file contains a datasources array with type: "prometheus" entries
   • Use make run which automatically sets the path to local_config/datasources.yaml
2. Authentication failures: Verify bearer tokens in secureJsonData
3. Query timeouts: Adjust QUERY_TIMEOUT environment variable
4. Query validation errors: Check query length and ensure non-empty queries
5. Client connection issues:
   • 400 Bad Request: Server restart - client will reconnect automatically
   • 406 Not Acceptable: Client must accept application/json, text/event-stream

Debug Mode

LOG_LEVEL=DEBUG make run

Health Checks

curl http://localhost:8080/health
curl http://localhost:8080/metrics | grep mcp_

Documentation

• SPECS.md - Technical specification and architecture
• LLM.md - Development guide for AI assistants
• TESTING.md - Local testing guide with bearer token examples

Contributing

1. Fork the repository
2. Create a feature branch
3. Make changes with tests
4. Run quality checks: make format lint test
5. Submit a pull request

License

Apache License 2.0