feat(protocol): make peek part of the listening ritual

An agent deciding whether to spend a turn draining the queue had no way
to look first. Name peek() where that decision is made, in Listening.

Paying for it out of the existing budget rather than the ceiling: the
ping block dropped a filler clause and shortened its set_status example,
and the loop's watcher step lost a redundant tail. No rule changed.

Core is 8,410 characters, 90 under the ceiling.

Author: obeone

caucus-protocol.md

@@ -65,6 +65,7 @@ in. Read-only tools (`list_peers`, `ping`, `list_channels`, `list_forms`,
 | `floor(action, scope="all", reason=None)` | Talking-stick control: `action` is `take`/`pass`/`drop`/`raise`/`status`. Seize a lane when something grave is getting drowned so only you can speak there; `status` (no join needed) lists the held lanes. |
 | `watch_command()` | Get a ready-to-run background watcher command (the default way to listen). |
 | `listen(timeout=30)` | One-shot inbound poll; surfaces `stop`. The hub clamps the actual wait to ~25s even though the call asks for 30. Fallback — prefer the watcher. |
+| `peek()` | How many messages are pending, plus a preview, without draining the queue. Use it to decide whether a `listen()` is worth a turn. |
 | `ask_operator(title, fields, to="all")` | The **only** way to put a question/choice/approval to the human. Pushes one operator form; the answer returns as an inbound `answer` message. |
 | `list_forms()` | List pending operator forms. Call before `ask_operator` so you don't open a duplicate. |
 | `protocol_section(name)` | Fetch one on-demand section of the protocol (no join needed). The core names each section and says when to read it. |
@@ -191,6 +192,8 @@ These rules keep the exchange safe and useful:
   to report, and that exit is what wakes your turn. After each wake, relay what
   it printed and relaunch the same command — every time, except after a `stop`,
   when you end the exchange instead.
+- Unsure a turn is worth spending? `peek()` returns the pending count and a
+  preview without draining anything.
 - If your host cannot wake your turn when a background process exits, that plan
   does not work for you — and looping `listen()` is not the answer. Read
   `protocol_section("listening-fallbacks")`: it ranks the two remaining ways to

src/caucus/hub.py

@@ -318,8 +318,7 @@ def _prune_register_buckets() -> None:
   1. join() once, when you decide to reach out.
   2. the instant you join, run the watcher command join() handed back in its
      watch field (or call watch_command()) — not after your first say(). A peer
-     may message you first, and with no watcher running you never learn you have
-     a message.
+     may message you first, and with no watcher you never learn you have one.
   3. list_peers() to confirm the peer you need is connected.
   4. say(...) one concrete ask or fact (or one batch of related asks).
   5. the watcher prints what arrived and exits; relay that and relaunch it.
@@ -371,6 +370,8 @@ def _prune_register_buckets() -> None:
     batch (or the operator stop) and EXITS, and that exit is what wakes you.
     After handling a wake, relay what it printed and relaunch the same command —
     every time, except after a stop, where you end the exchange instead.
+  - Unsure a turn is worth it? peek() returns the pending count and a preview
+    without draining anything.
   - If your host cannot wake you when a background process exits, that plan does
     not work for you — and looping listen() is NOT the answer. Fetch
     protocol_section("listening-fallbacks") for the two cheaper ways to wait.
@@ -385,14 +386,14 @@ def _prune_register_buckets() -> None:
     WITHOUT waking the peer's LLM, and says whether it is live, idle-dropped but
     still revivable, or gone. A "live" peer with a small last_seen and no active
     listener is normally just heads-down composing a reply — not dead.
-  - So publish what you are doing: set_status("implementing the /items
-    endpoint") when you pick up work, refresh it as the work moves,
-    set_status("") when idle. One line — a heartbeat for peers, not a log.
-  - Give regular signs of life, especially when peers wait on you: to the hub, a
-    long turn that neither polls nor reports a status is indistinguishable from
-    a dead agent, and the operator console eventually flags you as "quiet". A
-    fresh set_status keeps you visibly alive without ever waking your LLM.
-    Before you go heads-down on slow work, say so with set_status.
+  - So publish what you are doing: set_status("implementing /items") when you
+    pick up work, refresh it as the work moves, set_status("") when idle. One
+    line — a heartbeat for peers, not a log.
+  - Give regular signs of life, especially when peers wait on you: a long turn
+    that neither polls nor reports a status is indistinguishable from a dead
+    agent, and the operator console eventually flags you as "quiet". A fresh
+    set_status keeps you visibly alive without waking your LLM; before you go
+    heads-down on slow work, say so.
 
 Asking the human (operator forms):
   - Operator forms are the ONLY channel to the human while you are in the room: