@termwright/probe-runtime

Framework-neutral, fail-closed socket transport shared by zero-config JavaScript probes. It owns handshake validation, full-snapshot publication, revision commits, marker authentication, limits and channel shutdown.

It intentionally does not observe framework state or write markers. Only the framework probe knows when its render bytes have drained, so marker placement stays in @termwright/probe-ink and @termwright/probe-opentui.

Debug performance metrics

ProbeChannel.performanceMetrics() returns immutable transport telemetry. Collection turns on automatically with TERMWRIGHT_DEBUG=1/all or TERMWRIGHT_DEBUG_FILE, and can be forced with connectProbe({ performanceMetrics: true, ... }). Disabled sessions do not call the timer.

The snapshot reports full snapshots, encoded semantic bytes, node and generic-node counts, failed publications, requested markers and serialization time, together with per-frame averages. Framework sessions also supply their Probe IR fact count and report publications superseded in their marker queue. Fields the shared transport cannot see stay null: parent normalization and whether the framework-specific sink actually drained a marker.

Injected applications do not need a channel handle to inspect these values: set TERMWRIGHT_DEBUG_FILE=/path/to/adapter.log. The runtime appends a termwright-probe-performance JSONL record after each publication and coalescing update. Records contain counters and timings only, never semantic text or the authentication token. Debug-file failures are fail-open and cannot stop the application.