--- title: "Loggerhead — Your coding agent reads your app's logs, metrics, and traces." description: "Your coding agent reads your app's logs, metrics, and traces. One Mac app, no Docker stack, and nothing leaves your Mac." source: "https://getloggerhead.com/" --- # Loggerhead > Your coding agent reads your app's logs, metrics, and traces. Loggerhead is a native macOS app that receives OpenTelemetry logs, metrics, and traces from the software you run on your own machine, stores them in a DuckDB file on your disk, and serves the same data to your AI coding tool over the Model Context Protocol. ## What it is Loggerhead is a development tool, not a production observability platform. It is the window you keep open next to your editor while you build, test, and stage. It replaces a Docker stack of collector, database, and dashboard with one app you install from a disk image. Three signals share one store and one time base. Click a log line and open its trace. Click a span and read the logs it emitted. - **Logs.** Severity tints, service colours, text search, and a stream you can pause. - **Metrics.** Counters, gauges, and histograms in DuckDB. Group by any label key over any window. - **Traces.** A waterfall per request, spans grouped by service, and a jump from a span to its logs. ## What it needs - macOS 15+ · Apple silicon & Intel - No account, no sign-in, and no hosted service - No runtime to install. It is one Swift binary. - Notarised by Apple and free to start - No internet connection. It works offline. ## How telemetry arrives The app runs one OpenTelemetry receiver, the root, on `127.0.0.1`. It prefers port 4317 for gRPC and 4318 for HTTP, and it moves along a fixed ladder when another program holds a port. Every other collector is a branch that forwards into the root: a Docker host, a Kubernetes cluster over a tunnel, another Mac, or the application's own SDK. Loggerhead can also scrape a Prometheus endpoint on a schedule. Every record carries the ID of the collector that sent it. ## What your AI coding tool gets Loggerhead hosts a Model Context Protocol server inside the app, on loopback. Claude Code, Cursor, Codex, Windsurf, and any other MCP client read logs, metrics, traces, and telemetry-quality findings through it. Nine tools only read. Seven tools change the lint rules of a workspace or ignore a finding. Each of them needs a reason, and the user can undo the change on the Rules tab of the Linting page. One tool marks a finding fixed after a code change. No tool deletes telemetry. The endpoint is not reachable from another machine. See https://getloggerhead.com/AGENTS.md for the commands that connect a project. ## Telemetry linting Loggerhead reads what the application emits and reports the problems before production charges for them: debug lines nobody reads, labels with unbounded cardinality, an email address or a card number in a log field, an error that lost its trace context, and a metric that stopped arriving. Each finding carries a written fix you paste into the AI tool that already has the project open. It checks in two ways: - **Lint rules.** Deterministic checks, like a code linter. 42 rules read the last hour, and the same data gives the same findings. You turn each rule on or off and set its thresholds on the Rules tab of the Linting page. - **AI analysis.** A separate Pro check. One large prompt goes to a model over a window you choose, the last hour or the last 24 hours. It finds what a rule cannot, such as the same log line from two places or traces that do not line up. It uses Apple Intelligence on the Mac first, with no key, or an AI provider key you add. ## Pricing ### Free — $0 forever Everything a solo developer needs to see one app on one Mac. - Logs, metrics, and traces - One workspace with one environment - The Loggerhead receiver and one branch collector - One pull source and one scrape endpoint - MCP server for your coding agent - Telemetry linting: 42 rules, with the fix for your AI tool - Support by email ### Pro — $39 one-time For staging traffic, many collectors, and the alerting that catches a bad release. - Everything in Free - Unlimited workspaces and environments - Unlimited branch collectors - Unlimited pull sources - Standalone receivers and unlimited scrape endpoints - Keep data as long as you like - AI analysis, on your Mac or with your own key - Alerts, native notifications, and menu bar status - One year of updates, then keep the version you have - Renew the updates for $19 a year, only when you want them ### Lifetime — $89 one-time Everything in Pro, and every future release. Pay once and never renew. - Everything in Pro - Every future release of Loggerhead - No renewal, ever - A Pro licence upgrades to Lifetime for $50 ## Limits - macOS only. There is no Linux build, no Windows build, and no hosted version. - It is not a production observability platform and does not aim to be. - It only knows what was sent to it. A service that does not export to the receiver is invisible. - There is no public API. The MCP endpoint listens on loopback inside the app. ## Pages - [Documentation](https://getloggerhead.com/docs/) - [Documentation index for agents](https://getloggerhead.com/llms.txt) - [Every documentation page in one file](https://getloggerhead.com/llms-full.txt) - [Glossary](https://getloggerhead.com/docs/reference/glossary/) - [Download](https://getloggerhead.com/download) - [Changelog](https://getloggerhead.com/changelog) - [Site map](https://getloggerhead.com/sitemap.md) ## Who makes it Rubics Code (ABN 40 440 756 434), Australia. Support: support@getloggerhead.com.