What the server exposes
The Loggerhead MCP server is a small program, loggerhead-mcp. It speaks the Model Context Protocol over stdio to your coding tool, and it reads data from the Loggerhead engine over the local HTTP API. It never opens the database file itself.
| Tool | Purpose |
|---|---|
query_logs |
Search and filter log records by text, severity, and time. |
query_metrics |
Read time-series metrics by name pattern and time. |
query_traces |
Search traces by service, operation, duration, and time. |
get_trace |
Read every span of one trace by trace ID. |
get_receiver_info |
Report the effective OTLP ports of the root receiver, the conflict flags, and the addresses to send to. |
Resource
Section titled “Resource”| Resource | Content |
|---|---|
loggerhead://stats |
Total counts of logs, metrics, and spans in the database. |
What it cannot do
Section titled “What it cannot do”- It cannot write. No tool changes settings, deletes data, or sends telemetry.
- It cannot reach another machine. It talks to
127.0.0.1only. - It cannot see data that is not in Loggerhead. If a service does not send to the root, the tool cannot find it.
Why it goes through the engine
Section titled “Why it goes through the engine”DuckDB allows one process to hold the file. The engine holds it. The MCP server, the app, and any script all read through the engine’s API. That is what lets the app and your coding tool work at the same time.