Loggerhead

Loggerhead MCP server

Your coding agent reads your app's logs, metrics, and traces.

Loggerhead is a native Mac app that receives OpenTelemetry logs, metrics, and traces from the software you run on your own Mac, and stores them in a DuckDB file on your disk. The MCP server runs inside the app. This repository holds loggerhead-mcp, the small bridge that connects Claude, Cursor, Codex, Windsurf, or any other MCP client to it.

The tools read the telemetry. Seven tools change the lint rules of a workspace, each with a reason that the user sees and can undo in the app. One tool marks a finding fixed after a code change. The endpoint listens on loopback only. Nothing leaves the Mac.

The Loggerhead app must be installed and running. Download it first. The bridge exits when the app is not running. The free tier includes the MCP server.

Install

Claude Desktop

Download loggerhead-mcp.mcpb from the latest release and open it. Claude Desktop installs the extension.

Claude Code

claude mcp add loggerhead -- "/Applications/Loggerhead.app/Contents/Resources/loggerhead-mcp"

Cursor, Codex, Windsurf, and other stdio clients

Every stdio client takes the same two values. The .mcp.json in this repository is the file to copy:

{
  "mcpServers": {
    "loggerhead": {
      "command": "/Applications/Loggerhead.app/Contents/Resources/loggerhead-mcp"
    }
  }
}

The app itself writes this entry for you: open Settings › AI and click Add beside your tool.

The bridge finds the app by itself on a fixed ladder of local ports. You set no port, and it needs no permission to read the app's files. Full instructions: Set up the MCP server.

Tools

Tool	Purpose
query_logs	Search log records by text, severity, and time.
query_metrics	Read time-series metrics by name and time range.
query_traces	Find traces by service, operation, duration, and time.
get_trace	Read every span of one trace.
list_environments	List every workspace and environment on this Mac, with the receiver ports.
get_receiver_info	Report the effective OTLP ports and the addresses to send telemetry to.
query_improvements	List the telemetry-lint findings: noisy logs, unbounded labels, secrets, lost trace context.
list_lint_rules	List the lint rules of a workspace with their state, thresholds, exceptions, ignored findings, and recent changes.
query_ai_findings	List the findings of the last AI analysis run. It does not start a run.
set_lint_rule_enabled	Switch a lint rule on or off for a workspace, with a reason.
set_lint_threshold	Set one threshold of a lint rule for a workspace, with a reason.
reset_lint_threshold	Put one threshold of a lint rule back to its default, with a reason.
add_lint_exception	Hide the findings of one lint rule for a service, metric, attribute key, operation, or log message, with a reason.
remove_lint_exception	Remove one lint rule exception, with a reason.
ignore_finding	Ignore one lint finding by its id, with a reason.
unignore_finding	Stop the ignore of one lint finding, with a reason.
mark_finding_fixed	Mark one lint finding fixed after a code change, so the app judges it by the telemetry after the fix.

One resource, loggerhead://stats, reports the total counts of logs, metrics, and spans. Every parameter is in the tools reference.

Privacy Policy

The bridge and the server read telemetry from the Loggerhead app on the same Mac and hand it to the MCP client you connected. They collect nothing about you, they store nothing of their own, they share nothing with a third party, and they open no network connection except to 127.0.0.1. Data retention is the app's: the telemetry lives in a DuckDB file on your disk for as long as the app's retention setting keeps it, and you can delete the file. The full policy of the publisher, Rubics Code, is at https://getloggerhead.com/privacy. Contact: [email protected].

Registry

The registry name of this server is com.getloggerhead/loggerhead.

• MCP Registry name: mcp-name: com.getloggerhead/loggerhead

Licence

The loggerhead-mcp bridge and the files in this repository are under the MIT licence.

The bridge contains open-source Swift packages. The .mcpb bundle has Acknowledgements.txt with the licence text and the notice text of each package.

The bridge connects to Loggerhead, a proprietary Mac app by Rubics Code (ABN 40 440 756 434), Australia. The app has a free tier, and the source of the app is not public. The Loggerhead terms of service apply to the app.