Reply parks

Superseded, in part, by agent-and-avatar: there is no registry entry. A reply lives on Agent::status.reply, written by the avatar alone and read by anyone still holding the Arc. The decision below — deposit and park, never terminate — stands.

A returned value is a fact the registry holds, not a message the parent reads. A returning agent’s reply deposits its value on the agent’s own registry entry and parks the agent; the parent is woken with one line and fetches the value, when and if it wants it, with agents `read <name>. The replier stays — hidden, quiesced, under the idle lease — and a message wakes it into a new exchange. This supersedes the terminating half of reply-terminates-returning-agents; its other rulings — reply is mandatory, advertised to every returning agent, and its payload is the faithful FOValue — stand.

The complaint

Under 260623 a child’s reply was rendered to prose and pushed into the parent’s inbox as [agent 'x' finished]\n<text>, and the child’s entry was settled away. Two things were wrong with that, and they are the same thing seen twice.

The payload arrived unasked. A parent that spawned three explorers to keep their working out of its context got three reports dumped into it, in full, at the moment each happened to finish — exactly the flooding the spawn was meant to avoid. And the reply was prose: a structured verdict the child built as a record crossed the edge as text, to be re-read rather than bound.

The child was gone. The one agent that knew the answer’s provenance could not be asked a follow-up; the parent’s only recourse was to spawn again and re-explain. Yet the machinery to keep it was already there — the one-hour idle lease, the five-minute tab demotion, the Engaged park — armed only for a child a human had typed at.

The decision

• reply deposits and parks. The desk stages the value as before; when the batch drains the child writes the FOValue to its registry entry, cancels its proper descendants (a reply still means “this subtree’s work is done”), and parks waiting for a message. Cancel and the idle lease end that park as they end any Engaged one; a non-reply finish — Failed, Stopped, Cancelled — stays terminal and keeps its one-line tag.
• The parent is woken, not fed. The child posts a notice that renders as one line, [agent 'x' replied — agents reply ‘x’ fetches it]`. A parent parked on its children needs some wake; the payload is not it.
• Both verbs live in the agents family; the standalone reply builtin is gone. The child hands up with agents `reply <value> (refused on a non-returning agent, keyed on returns as before; answers the roster like every other tag). The parent fetches with agents `read <name>, which answers the record [name: Str, reply: <the deposited value>] — a string reply is a Str, a record a record — so let r = agents read ‘x’` binds it and the rest is ral. It is idempotent until the child replies again or is reaped; a child that has not replied refuses with a sentence saying so. It is the one tag that does not answer the roster, because its answer is not the fleet’s state but one agent’s value.
• The family’s type pays for read. agents was <…> → F roster because every tag answered the roster; read answers a value of unknown shape, so the scheme becomes ∀α β ρ. <list | start … | message … | cancel Str | reply β | read Str | ρ> → F α — the pin-read/from-json precedent. list and start still answer the roster at runtime; they are no longer checked to. Accepted knowingly over a separate pin-read-shaped verb, to keep one word for the fleet.
• The roster says what each agent is doing. Rows carry state — `busy, `waiting-on-agents, `replied, `waiting — and idle-s, the seconds since the agent parked. Both are derived at listing time from registry facts, so the roster still reads as a fact, not an intent.
• A parent holds for busy children, not live ones. HeldByChildren now reads “some child has not parked”. Otherwise a parent whose children had all replied would wait out their hour.
• Any message renews the lease. The 260623-era rule that only a human message renews is refined: a message — the parent’s agents `message or a human’s typed line — is an exchange and renews; focus, listing, and /resources probes still do not. Attention alone still never immortalises a child.
• Nobody quiescent is badgered. The nudge layer has one gate for every nudge kind — the reply reminder, the pin reminders, context pressure: an agent is nudged only if it has not replied, is waiting on no detached shell work, and has no busy children. A standing reply stands; a wait is a wait.

What follows

Synod’s Law B (exchange-ends-at-fleet-quiescence) reads “no live children” as “no busy children”: an exchange ends once every child has replied or died, while the repliers linger under their lease.

The reply prompt (reply.md`) no longer tells the agent that reply ends its run: it may be woken by a message and asked for more, and answers again with reply.