Query Loki Logs with LogQL

Simple Loki MCP Server

Loki MCP Server is a Model Context Protocol (MCP) interface for querying Grafana Loki logs using logcli. The server enables AI assistants to access and analyze log data from Loki directly.

Features

• Query Loki logs with full LogQL support
• Get label values and metadata
• Authentication and configuration support via environment variables or config files
• Provides formatted results in different output formats (default, raw, JSON lines)
• Automatic fallback to HTTP API when logcli is not available in the environment

Prerequisites

• Node.js v16 or higher
• TypeScript
• (Optional) Grafana Loki logcli installed and accessible in your PATH. If logcli is not available, the server will automatically use the Loki HTTP API instead
• Access to a Loki server instance

Installation

Installing via Smithery

To install Simple Loki MCP Server for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @ghrud92/simple-loki-mcp --client claude

for MCP

{
  "mcpServers": {
    "simple-loki": {
      "command": "npx",
      "args": ["-y", "simple-loki-mcp"],
      "env": {
        "LOKI_ADDR": "https://loki.sup.band"
      }
    }
  }
}

npm

1. Clone the repository:

git clone https://github.com/ghrud92/loki-mcp.git
cd loki-mcp

2. Install dependencies:

npm install

3. Build the project:

npm run build

Available MCP Tools

query-loki

Query logs from Loki with filtering options.

Parameters:

• query (required): Loki query string (LogQL)
• from: Start timestamp (e.g. "2023-01-01T12:00:00Z")
• to: End timestamp (e.g. "2023-01-01T13:00:00Z")
• limit: Maximum number of logs to return
• batch: Batch size for query results
• output: Output format ("default", "raw", or "jsonl")
• quiet: Suppress query metadata
• forward: Display results in chronological order

get-label-values

Retrieve all values for a specific label.

Parameters:

• label (required): Label name to get values for

get-labels

Retrieve all available labels.

No parameters required.

Configuration

You can configure Loki access using:

Environment Variables

• LOKI_ADDR: Loki server address (URL)
• LOKI_USERNAME: Username for basic auth
• LOKI_PASSWORD: Password for basic auth
• LOKI_TENANT_ID: Tenant ID for multi-tenant Loki
• LOKI_BEARER_TOKEN: Bearer token for authentication
• LOKI_BEARER_TOKEN_FILE: File containing bearer token
• LOKI_CA_FILE: Custom CA file for TLS
• LOKI_CERT_FILE: Client certificate file for TLS
• LOKI_KEY_FILE: Client key file for TLS
• LOKI_ORG_ID: Organization ID for multi-org setups
• LOKI_TLS_SKIP_VERIFY: Skip TLS verification ("true" or "false")
• LOKI_CONFIG_PATH: Custom path to config file
• DEBUG: Enable debug logging

Note: When the client is using the HTTP API mode (when logcli is not available), the same configuration parameters are used to authenticate and connect to the Loki server.

Config Files

Alternatively, create a logcli-config.yaml file in one of these locations:

• Custom path specified by LOKI_CONFIG_PATH
• Current working directory
• Your home directory (~/.logcli-config.yaml)

Example config file:

addr: https://loki.example.com
username: user
password: pass
tenant_id: mytenant

Usage

Start the server:

npm start

For development:

npm run dev

Implementation Details

Automatic Fallback to HTTP API

The server will automatically check if logcli is installed and available in the environment:

1. If logcli is available, it will be used for all queries, providing the full functionality of the CLI tool
2. If logcli is not available, the server will automatically fall back to using the Loki HTTP API:
   • No additional configuration is needed
   • The same authentication parameters are used for the HTTP API
   • Response formatting is consistent with the CLI output
   • Default limit of 1000 logs per query is applied in both modes

This automatic detection ensures that the server works seamlessly in different environments without manual configuration.

Development

# Run linter
npm run lint

# Fix linting issues
npm run lint:fix

# Run tests
npm run test