[backnotprop]

What the person sees

The owner's report: after replying in the Inbox, the reply said "Saved for Claude Code. It sees it when it checks.", which reads as if it were dropped, or as if the agent had to poll for it. The line under the person's last reply (or New message / compose message) now says where it is, from what the Inbox knows about the session's connection right now:

State	Line
Waking agent, working	Queued · Claude Code is working; it gets this when its turn ends. with a Send now button
Waking agent, idle	Sending to Claude Code… (lands within seconds)
After Send now	Sending to Claude Code now…
Delivered	Delivered to Claude Code, 5:12 PM (unchanged)
Agent that only reads the thread (MCP, OpenCode 1)	Saved for Claude Code. It sees it when it next reads this thread.
Session ended / Not delivered	unchanged

The Sent row in the list reads "Queued for ; it gets this as its next turn." for a waking agent (the row's additive sent.wakes), "Saved for . It sees it when it next reads this thread." otherwise.

Can a Claude Code plugin steer into a running turn?

Yes, but not with $.prompt.submit. From the engine's own API (2.1.301 types and the plugin-authoring reference): $.prompt.submit "queues a prompt that starts a turn of its own once the session is idle (never folded into a running turn)". $.session.append({ message: { type: 'user', content } }) "REALLY appends: a user-role row … the model reads it … The row is in the list at once and in a running turn's requests from the loop's next top." So Send now uses $.session.append, no interrupt needed. The engine harness (claude plugin test) confirms the mod's call is accepted and stored as a user row.

What Send now does per host

• Server: POST /api/inbox/messages/:id/send-now (same-origin, serverSession) writes deliver_now_at on the message. Refused when the recipient's connection does not poll now or cannot deliver mid-turn (409 send_now_unavailable), when delivered (409 already_delivered), or for a message that goes to no session (422 not_addressed). The bridge command carries now: true only on a poll that says send_now; a held poll answers at once. A connection that could not steer posts send_now_failed, which clears the mark (the line reads Queued again). On the device door as contract 7.58.
• Order: once a reply carries now, the connection delivers the waiting replies at once, oldest first, so an urgent reply never overtakes an older one to the same session.
• Claude Code mod: send_now (poll and state events) is true only while a reply could go in now, so while this session's own Ask question holds it Send now is not offered and a pressed one reads Queued. Decided right before the append, after the fresh check, lease and claim. Into the running main turn as one user row ($.session.append) plus a transcript notice, never into this session's own "Ask this session" turn (running or queued: the reply waits for idle there). A turn that ended before the append gets the reply as a turn; one that ended or changed during it gets one short pointer turn at once; otherwise the row is tied to its turn id, and a turn that ends with no model request after it gets the pointer. Advertised only on an engine at least 2.1.301 (from $.session.version(): claude plugin validate refuses typeof $.session.append), and no more after an engine refuses a row.
• Pi: pi.sendUserMessage(text, { deliverAs: "steer" }), delivered when Pi starts the message (message_start).
• OpenCode 2: session.prompt({ delivery: "steer" }), delivered only on session.inbox.delivered for that row id (or session.inbox.delivery.changed to queue). If the run ends first and the row is not delivered within 3 s, after 60 s, or at once if the event stream ends, it is sent as a queued turn ending with "If this same reply () already appears above, it is a repeat; answer it once." Because OpenCode cannot withdraw the steer row and promotes it with that turn (fix(opencode): a tool launch's session-URL notice never wakes an idle root #1734), the plugin's context/generate hooks drop the later of the two copies from every model request. Offered only while the event stream runs.
• OpenCode 1 and older connections: never send the poll field send_now, so Send now is never offered.
• Nothing is ever aborted. Claim-once holds: the same claim folder and lease as a normal delivery.
• The line under the reply also reads Queued for a message sent without the wake mark (the stdio shim inside Claude Code) while its session's connection polls.

A bug this turned up

The owner's "Claude is busy constantly" had a second cause: every hook hears a subagent's turn.start, the mod counted it as the session's running turn, and its end was filtered out at turn.complete. So once a background subagent started, the session read as busy for good and Inbox replies never went in. PlannotatorMod.onTurnStart now ignores subagent turns. Proved in the engine harness (fails without the fix) and in controller.test.ts.

Tests

• packages/server/inbox-send-now.test.ts: routes, guards, the poll's now, a held poll answering on Send now, sent.wakes, and agent-link's steer for Pi/OpenCode (busy → steer, idle → deliver at once, no steer → refused).
• apps/hook/hooks/mod/inbox.test.ts 12 to 17: the mod against a real Inbox (busy session, Send now → one user row, no turn, Delivered; the row landing as the turn ended → one pointer turn; the turn ending just before the append (the reviewer's repro) → a turn, no row; the turn ending during the append → the pointer at once; this session's Ask question running or queued → nothing until idle; oldest first). send-now-engine.test.ts: the version gate.
• apps/opencode-plugin/inbox-v2-wake.test.ts: the steer counted delivered only on its session.inbox.delivered, and the queued fallback. apps/pi-extension/inbox-send-now.test.ts: the steer, delivered on message_start.
• apps/hook/tests/register.test.ts (engine harness): the row through $.session.append; an engine older than 2.1.301 never offers it; a background subagent's turn no longer holds a reply.
• packages/inbox/deliveryLine.test.ts, DOM packages/inbox/sendNow.test.tsx (added to the test.yml DOM list).
• tests/e2e/inbox-send-now.spec.ts on the compiled binary (desktop light/dark and a phone); inbox-compose, inbox-ended-session, inbox-new-message specs updated to the new lines and pass.

Screenshots (light, dark, phone): .product/drafts/inbox-queued-send-now/ in the owner's checkout.

Docs: AGENTS.md (Questions and Send, the mod's Inbox paragraph, Ask this session's busy, agent connections, server table), plannotator inbox --help, the marketing reference page, and the mobile contract (7.58).