0141. The console watches him type

Accepted 2026-08-29.

Context

The operator console showed a spinner for the whole of a turn and then the whole answer at once. Pi streams: the captain's session subscription already saw text_delta for every token and threw the text away, keeping only a deduplicated activity phase — Thinking…, Responding… — for the loader. The answer reached the transcript once, after runDurableTurn resolved.

Two things stood in the way of simply forwarding those deltas.

The tail is a durable, replayable, multi-surface log. Every event is a line in events.jsonl with a cursor, and replay re-reads and re-parses that file per request. Token-granular durable events would multiply the log by three orders of magnitude, churn cursors, blow through retention trimming, and make every surface pay to replay a message character by character. Streaming text is not a record of what happened; it is a view of something that has not happened yet.

The tail was also a poll: the client asked, and on an empty page slept 250ms. Even settled messages arrived up to a poll interval late, so no publishing scheme could feel live through it.

A third problem was already there and would have become visible the moment drafts rendered: only the last assistant message of a turn was published. lastAssistantText was overwritten at each message_end, so anything he said before reaching for a tool — "let me check the config" — was dropped. A draft that streamed and then vanished would have read as a bug.

Decision

The captain's answer reaches watching surfaces twice: as a volatile draft while he types it, and as the durable message that settles it.

• A draft is volatile. ConversationStore.setLiveDraft holds the message being typed in memory, per conversation, and it rides the tail page as an optional live field. It never enters events.jsonl, so replay, cursors, retention, and every surface that only wants the record are untouched. The text is cumulative, not a delta: a surface that misses a page still renders the right thing, and a dropped draft costs nothing.
• The tail parks instead of polling. A tail carrying waitMs waits for the next change to that conversation — a new event, or a draft the caller has not drawn (liveSequence) — up to the store's own cap. An idle conversation costs one request per wait window; a streaming one answers at the pace of the round trip. replay never waits, and a request without waitMs answers immediately, so nothing that has not asked to park can hang.
• Drafts are paced, not throttled per token. The captain emits at most one draft per 60ms — roughly sixteen frames a second, which reads as typing — and opens the gate again at each message boundary so a new message shows its first token at once.
• Every message he finishes is published. The durable message event moves from "after the turn, the last text" to "at each message_end, if it has text". The transcript now carries what he said before a tool call, in the order he said it, and each draft has a durable event that settles it.
• The surface settles the draft in place. The console draws a draft into a real transcript block from the first token; the settled message replaces that block's content rather than appending a second one. A draft that ends with no settled message behind it — an interrupted or failed turn — keeps the words he got out.

Thinking stays a loader phase. Streaming reasoning raises a separate question about whether thinking belongs in durable history at all, and it is not answered here.

Consequences

• The console reads like pi's own: text appears as he writes it, tool blocks interleave where they actually happened, and the spinner is only for the parts where nothing is being said.
• The wire contract grew three optional fields (live, liveSequence, waitMs) and one tail item kind. A surface that ignores all of them behaves exactly as before, which is how the menu bar and local voice chat keep working unchanged.
• The parked request is bounded twice: by the caller's waitMs, capped at OPERATOR_CONVERSATION_TAIL_WAIT_MS_MAX, and by the store's own window, which sits under the relay's 30s upstream dispatch timeout. The dispatch contract takes an AbortSignal so a surface that goes away cancels its parked tail rather than stranding it.
• More durable message events per turn than before — a handful, not thousands. Retention math is unchanged in shape.
• A draft is per conversation, not per run. While a steered turn (ADR 0091) has two runs in flight, the draft belongs to whichever is generating, and the last run to settle takes it down.