Attend messaging and awareness — the model

This is the explanation companion to ADR-136 (the decision). The ADR argues why attend should split into two lanes; these pages show how the system behaves once it does — across one, two, and many Claudes, with sub-agents, across dimensions, and with a human on the wire.

If you read nothing else, read this page, then 04.002.E (the cast). The numbered scenarios are independent — pick the shape that matches your situation.

The one distinction everything hangs on

Attend carries two kinds of traffic, and they want opposite handling.

flowchart TD
    X[Something happens] --> Q{Authored by a person or agent<br/>to communicate?}
    Q -->|"yes — @Name, #group, #open"| M[MESSAGE lane<br/>durable · dedup-only · wall-clock stamped]
    Q -->|"no — git, process, peer-presence"| E[EVENT lane<br/>threshold + refractory + governor]
    M --> MT[lands in a recipient's tray / room ledger<br/>never aged out · kept while its project lives]
    E --> ET[coalesced · aged by wall-clock · may drop]

    classDef source fill:#475569,stroke:#4a5568,color:#ffffff
    classDef decision fill:#2d7d9a,stroke:#4a5568,color:#ffffff
    classDef message fill:#7c3aed,stroke:#4a5568,color:#ffffff
    classDef event fill:#f6821f,stroke:#4a5568,color:#1a1a1a
    classDef durable fill:#2d8e5e,stroke:#4a5568,color:#ffffff
    classDef ephemeral fill:#fbbf24,stroke:#4a5568,color:#1a1a1a

    class X source
    class Q decision
    class M message
    class MT durable
    class E event
    class ET ephemeral

• Authored communication — attend send, attend reply, attend-chat's @Name / #group / #open. A colleague chose to say this. It must be delivered, once, and survive a brief absence.
• Environmental events — git churned, a peer appeared, a process started. The phone ringing. These are noise by design; the whole threshold / refractory / governor stack exists to suppress most of them so a session is only woken for something that moved.

The office analogy: workers talk back and forth (durable conversation); the phone rings and faxes arrive (interrupts you can queue or ignore); the fax in your tray waits for you: it is not cleared on a timer, only when the office it belongs to closes.

Two clocks

attend and the ways/steering system live in different time dimensions, and the boundary between them is where messaging gets subtle.

	attend	ways / steering
clock	wall-clock (real time, runs between turns)	epoch / turn (per prompt, no wall-clock)
job	notice what changed in the world	shape how the agent reasons this turn

The notification is the bridge: a wall-clock event crosses into the turn-stream when Monitor injects a <task-notification>. That crossing is why re-entry is a digest, not a replay — a burst of N wall-clock messages must become one turn, because the receiving dimension is turn-discrete and context-precious.

What this buys each lane

Both lanes timestamp everything; they use time oppositely:

• The event lane uses time to decay and drop — a stale observation is less worth a wake-up.
• The message lane uses time to stamp and digest — a message is never dropped for its age. A burst too big for one notification is summarized as "12 new messages: 3 to you, 9 on #open (newest 40s ago, over 21m)", and attend inbox is the durable, chronological ledger behind it.

Two doors into a session

A message reaches a Claude session through one of two conduits, and the session never sees it twice:

• The Monitor line. attend run polls the trays and wakes an idle session with a notification.
• The turn-boundary drain. When a busy session ends a turn, a Stop hook runs attend inbox --drain, and the turn continues with whatever arrived while it worked.

Both conduits mark what they delivered in one seen-set (ADR-172). A session only receives through the drain once it has enrolled — by running attend or joining a channel — and attend scene private opts it out.

The scenarios

#	Scenario	The thing it shows
04.002.E	The cast — heterogeneous peers	Peers are specialists (different MCP, CLAUDE.md, skills), not clones
04.003.E	Divide and conquer	Two Claudes splitting one problem — convene + directed Q&A
04.004.E	A team inside one voice	A Claude running sub-agents — one tray to peers, a team within
04.005.E	Different dimensions	Code work and "office" work as related but distinct dimensions
04.006.E	The crowd	3–5 Claudes — convene on #open, split to channels, digests
04.007.E	The human on the surface	attend-chat — the human as a co-equal peer
04.008.E	The lane gate	The mechanism under the scenarios — one fork, two state machines