{"version":"2.1.221","anchor":"claude-attach-now-measures-time-to-interactive","canonical_anchor":"claude-attach-now-measures-time-to-interactive","heading":"claude attach now measures time-to-interactive","tier":"internal","area":"Sessions","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.221\/e\/claude-attach-now-measures-time-to-interactive","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.221","markdown":"### `claude attach` now measures time-to-interactive\n\nAttaching to a background session now times how long it takes to paint and reach an idle prompt.\n\n**What**\n\nAttaching to a background session records how long it takes to reach first paint and an idle prompt, alongside how much of the transcript was loaded and rendered.\n\n**Details**\n\n- A gesture record is created up front and the child's output is watched for content-paint and prompt-idle marks.\n- `tengu_bg_attach_outcome` gained `attach_ms`, `content_paint_ms`, `prompt_idle_ms`, `msgs_loaded`, `msgs_in_jsonl`, `msgs_rendered_at_first_paint`, `first_frame_kind` and `marks_expected`.\n- Daemon boot is marked when the daemon starts.\n- Error exits (crash loop, respawn failure, daemon unavailable) flush the gesture with a 750 ms race before exiting.\n\n**Evidence**\n\n`msgs_rendered_at_first_paint`\n\n- Area: Sessions\n- Names: `claude attach`\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 0\/5"}