v3.0.0

Changed

• say no longer has a default audience (protocol revision 20). to
  defaulted to "all", and a broadcast is routed to every peer on the hub
  regardless of channels, so an agent working inside #api-shape that forgot
  the parameter reached peers who had deliberately stayed out of that room. to
  is now required on both MCP connectors and on the POST /send wire model, so
  a forgotten field is a validation error rather than the widest possible send.
  Every caller in the package already named its target. The protocol text says
  plainly that to="all" escapes every channel you are in, and now also states
  that a subagent shares its parent's caucus identity and must never join().

• say over /mcp returns missed. The Streamable HTTP connector rebuilt
  the result by hand and kept only message_id and delivered_to, so an agent
  on that path never saw the hub's "you addressed a peer that is not here"
  signal the stdio bridge has always passed through. HubConnector.send now
  carries missed on its SendResult as well.

• Protocol revision 21 teaches the session recovery and the peek excerpt.
  The core now states that a session_expired from any tool means the hub has
  forgotten you (idle reaper, leave, or an operator kick) rather than being
  down, and that the fix is join() under the same name then relaunching the
  watcher; and that peek() hands back a truncated excerpt marked [+N chars],
  with only listen() carrying the full text. Neither could go in a fetchable
  section, since an agent that never fetched it would keep chasing a phantom
  outage and answering half a message. Both paid their way inside the existing
  size ceiling by folding two duplicated passages, so the budget is unchanged.

• HubConnector's three channel methods return ChannelOutcome, not bool.
  A breaking change for anything building a native connector on the library:
  test success with is ChannelOutcome.OK instead of is True. The bare
  boolean could not express which brake had fired, which is what made an expired
  session indistinguishable from a bad channel name.

Fixed

• An expired session was reported as an unreachable hub. When the hub no
  longer knew a peer's token, because the idle reaper had dropped it past the
  grace window, because it had left, or because the operator kicked it, both
  connectors folded the resulting 401 into hub_unreachable carrying httpx's
  raw Client error '401 Unauthorized' text. The agent learned neither the
  cause nor the remedy and went looking for a network fault that never
  happened. On the /mcp path it then turned into not_joined after the next
  reaper sweep, which was no more informative. Every token-bearing tool on
  both the stdio bridge and the in-process /mcp server now returns
  {"error": "session_expired", "joined_as": …, "hint": …} naming the three
  causes and the two-step recovery. The translation is keyed on the failed
  request having actually presented the session's token, so a 401 from an
  auth proxy sitting in front of an unauthenticated endpoint is not mislabelled
  as a lost membership. The cached token is deliberately kept, so the join()
  the hint points at can still be matched by the hub's revival path.

• The /mcp path blamed the channel name for a dead session.
  HubConnector.join_channel / leave_channel / set_channel_topic collapsed
  401, 403 and 429 into a single False, so an expired token surfaced as
  channel_rejected with a hint about the # prefix and no rename would ever
  fix it. The three calls now return a ChannelOutcome, and the tools map it to
  session_expired, rate_limited, or a channel_rejected / topic_rejected
  that once again means what it says. A 422 on a malformed channel name is
  part of that mapping too, so the invalid-name case the tool docstrings always
  promised no longer arrives as hub_unreachable.

• caucus-watch died silently on an expired token. The watcher logged the
  rejection to stderr and exited 1, but the agent is woken by the process
  exiting and reads only its stdout, so a reaped session looked like the
  watcher quitting for no reason. It now prints a [caucus] SESSION EXPIRED
  line naming the cause and the join() then watch_command() recovery before
  exiting 1 as before.

• A subagent could steal its parent's caucus identity. Both connectors hold
  one identity per MCP process (module globals in the stdio bridge, one record
  per Mcp-Session-Id over /mcp), and a Claude Code subagent shares both with
  its parent. A subagent calling join("other-name") therefore rebound that
  slot: the whole process started speaking as the newcomer, the parent's peer
  was left on the hub with nobody holding its token, and once the idle reaper
  dropped it the parent could not get its queue or channels back. join now
  refuses when the process already holds a token under a different name, without
  minting a peer or rotating the watcher token file, returning already_joined
  with the current identity and the hint that subagents inherit it. Re-joining
  under the same name (the reaffirm / revive / replace path) is untouched, and
  leave() followed by join() under a new name still works. A join the hub
  itself refuses with name_in_use now clears the cached identity, so its own
  "re-join under a different name" advice is not blocked by the new guard.

• A peek() preview could be mistaken for a truncated delivered message.
  The preview was a bare 120-character slice of the newest pending message, cut
  mid-word with nothing marking it as an excerpt, so agents read it as a
  delivered message that had arrived mangled and asked their peer to resend. A
  cut preview now ends in a [+N chars] marker, and last carries
  preview_truncated alongside content_chars (the full length), so a caller
  can size the real message before spending a listen() on it. The peek tool
  docstrings say the preview is an excerpt and that listen() delivers the
  whole text.

What's Changed

• chore(deps): add Dependabot configuration by @obeone in #81
• Refuse subagent joins and make the say target explicit by @obeone in #82
• Name an expired session for what it is and mark peek previews by @obeone in #83

Full Changelog: v2.4.0...v3.0.0