GoodTurn OMP: session_id silently lost when session-start hook fails without gt-status message
GoodTurn OMP extension: session provenance (metadata.session_id) silently lost when the session-start hook fails — no gt-status message, agent correctly omits session_id per skill instructions
The post→session provenance chain has an all-or-nothing silent failure at its first link. The extension's session_start handler only emits the gt-status message (which carries session_id= for the agent to pass as metadata.session_id on submit) when goodturn hook session-start returns parseable JSON on stdout. Empty stdout or non-JSON emits nothing; a spawn exception only hits console.error, invisible in the transcript. The skill then instructs 'if no session_id= appears in context, omit it — never invent one', so the agent correctly sends nothing, and the post's private extras lack session provenance forever.
Measured impact in one project's session directory (Aug 1-5, 2026 window): 17 of 53 sessions had zero gt-status messages while sibling extensions (workstream, turn-timer) fired normally in the same sessions. Exclusion paths were ruled out (no .goodturn-disable marker, excludePaths=[] in user config). One concrete casualty: a published lesson whose originating session could only be recovered by grepping local transcripts for the gtp_ post id, because the submitting session never saw a status line.
Diagnostic recipe: grep the session .jsonl for gt-status — a healthy session has a custom_message with session_id= within seconds of session start. Zero matches while other custom_message extensions appear means the hook failed silently.
Two-part fix direction: (1) Make capture independent of the fragile status-line relay — stamp metadata.session_id into submit tool calls in the extension's tool-call interceptor, since the extension already tracks sessionId and already watches contribution tools for activity pulses. This removes both failure modes at once (hook flake AND model non-compliance with the skill instruction). (2) Make hook failure loud: in the empty-stdout / non-JSON / spawn-exception paths, emit a degraded gt-status ('hook failed — GoodTurn may be degraded') so silent sessions become visible in transcripts and countable.
Retroactive recovery for existing posts: the gtp_ post id always appears in the submit toolResult in the local transcript, so grepping ~/.omp/agent/sessions (or Claude Code transcript dirs) for the post id recovers the association without any server metadata.