Starts the local HTTP log-ingestion server that instrumented code sends structured log events to. Must be called before any code can be instrumented or executions run. Also lazily opens the .log-probe/ SQLite storage for this project on first call.

Stops the local HTTP log-ingestion server. Stored sessions/hypotheses/logs are unaffected.

Reports whether the ingestion server is running, its URL, and basic counters.

Starts a new hypothesis-driven debugging session for a bug. All hypotheses and executions are tracked under a sessionId. Call this first, before creating hypotheses or executions.

Lists debugging sessions, most recently updated first.

Fetches full detail for a session: its hypotheses and execution summaries. Use format=markdown for a human-readable rendering.

Closes out a debugging session once the root cause is found and fixed (or the investigation is abandoned). Call knowledge_base_export first if you want a written record of the investigation.

Mints a new executionId for a process/request/test run you will trigger yourself (already running externally, or you'll reproduce it manually). Instrumented code must include this executionId in every log event it POSTs to the ingestion server. Requires probe_server_start to have been called first. For processes you want log-probe-mcp to launch and capture directly, use execution_run instead.

Spawns command as a subprocess with LOG_PROBE_URL/LOG_PROBE_EXECUTION_ID/LOG_PROBE_SESSION_ID auto-injected into its environment, so any instrumentation you've added can POST straight to the ingestion server without you wiring the correlation IDs by hand. Stdout/stderr are also captured line-by-line as logs (stderr as level=error), merged with any HTTP-posted structured logs in execution_get_logs. Waits for the process to exit (or timeoutMs to elapse). Requires probe_server_start to have been called first. Best for scripts, one-off repros, and test runs (e.g. running a flaky test N times); for long-running services, use execution_create instead.

Records the outcome of an execution that log-probe-mcp could not observe exiting on its own (i.e. one created via execution_create, not execution_run).

Lists executions for a debugging session with log-count summaries, most recent first.

Fetches the structured logs recorded for a single execution, in chronological order, optionally filtered by hypothesis, level, time range, or a text search over the message.

Diffs two executions' logs, grouped by normalized (source, level, message) so it tolerates differing data payloads (timestamps, ids). Returns log lines only present in A, only present in B, and lines common to both with their counts. This is the tool for flaky-test-style debugging: run the same thing repeatedly with execution_run, then compare a failing run against a passing one to isolate exactly what diverged.

Records a falsifiable hypothesis about the root cause of a bug within a debugging session. Form several distinct, competing hypotheses rather than one — the point of instrumentation is to gather evidence that can confirm some and refute others.

Marks a hypothesis confirmed/refuted/inconclusive based on evidence gathered from logs, and/or links it to the execution(s) that provided that evidence. This is the durable record that knowledge_base_export later turns into a written debugging knowledge base.

Lists hypotheses for a debugging session, oldest first.

Returns everything needed to instrument target code: the live ingestion endpoint (or a placeholder if probe_server_start hasn't been called yet), the LogEvent JSON schema, the env vars execution_run/execution_create inject, and ready-to-paste snippets per language. Use this before inserting any instrumentation so calls match the contract exactly.

Explains how to debug using log-probe-mcp: reconnaissance, forming falsifiable hypotheses, instrumenting code, reproducing, analyzing real runtime data, converging on a root cause, and resolving. Call with no arguments for the full guide, or a specific stage once underway. Read this before starting a debugging session if you haven't used log-probe-mcp before.

Writes .log-probe/knowledge/.md summarizing the root cause, confirmed/refuted hypotheses with evidence, and notable executions for a session, and refreshes .log-probe/knowledge/INDEX.md linking every exported session. This is the durable, written record analogous to a hand-maintained debugging notes file — call it once a session has reached a conclusion (or is being abandoned) so the investigation isn't lost.