Source Intelligence
Follow Discord

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

← All of v2.1.221 Home All releases ←olderv2.1.220 v2.1.222newer→
Claude Code v2.1.221

Much richer background-attach timing telemetry

Under the hood
Useful2 Signal0
Sessions

Attaching to a background session now records detailed timing, including a 30-second timeout flag.

What

tengu_bg_attach_outcome gains a large set of timing and content fields, purely observational.

Details
  • New fields: attach_ms, content_paint_ms, prompt_idle_ms, timed_out, attach_censored, marks_expected, first_frame_kind ("real", "dimhint", "unknown"), surface, daemon_booted, attach_cold, msgs_loaded, msgs_in_jsonl and msgs_rendered_at_first_paint.
  • Measured from a caller-supplied t0, with a 30s watchdog that flags a timeout when no paint marks arrive.
  • The same fields are now attached to the connect-throw error path, failure_class connect_throw, and to detach and error results.
  • None of these field names exist in 2.1.220.
Evidence

attach_censored

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.221 →