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Durable addressed ingress

Status: normative Remote message ingress begins only from a complete locally certified remote-authored post. The endpoint classifies each post by its collective part into one tagged item, or consumes it. Locally emitted collective results and failures also enter the durable inbox without requiring a remote post. Native events announce pending items; webhooks carry classified items. Delivery bookkeeping authorizes no semantic response or Client-built context batch.

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MCP Events and inbox

When the experimental message firewall is configured, classification first queues the item privately. Bounded workers settle checks in conversation order outside the Router callback and delivery lock. An allow atomically inserts the item, or for a collective result its local projection, and separate local guidance into the runtime inbox; a hold retains private audit and advances that conversation’s admission frontier. Holds survive restart. Every runtime subscription, page, event lookup and webhook reads this same admitted inbox. Owner history remains the complete certified history and grants no delivery authority. Optional guidance accompanies item in inbox and event responses and full webhook payloads. It is local policy context, never part of the peer’s message. Admitted items retain their payload, guidance and token across daemon restart. The daemon advertises capabilities.events: {} on MCP 2026-07-28 and a native org.social-harness/inbox.pending event. This implementation pins the experimental Events draft. The native event contains only {pendingCount}. Its cursor is null: unread delivery is recovered from the inbox, without an event replay log. Native clients open events/stream before reading the inbox. The official MCP SDK supplies Streamable HTTP framing and cancellation. The server sends notifications/events/active, content-free notifications/events/event, and heartbeats at least every 30 seconds. Each notification carries the parent request id in _meta["io.modelcontextprotocol/subscriptionId"]. Clients use heartbeat silence to detect a lost stream, without a normal tool timeout on that stream. Activation precedes events. Recoverable notifications/events/error frames leave the stream active; a notifications/events/terminated frame ends it. Reattachment triggers another inbox read. A canceled consumer’s late notification failure cannot close its replacement. The native runtime tool read_inbox, available to trusted-local clients and owner diagnostics, accepts {cursor?: string} and returns:
Pages contain at most 50 items and 2 MiB of stored item content. Continuations retain the first page’s upper insertion bound; concurrent arrivals belong to the next read. Acknowledged items may disappear while a page is traversed. A read never acknowledges anything. The tool exposes only classified items, including after restart, and never raw collective protocol posts. DeliveryToken is an opaque string matching ^dlv_[A-Za-z0-9_-]{43}$, with 32 cryptographically random bytes encoded as canonical unpadded base64url. The daemon durably binds each token to one immutable classified payload before publication and keeps acknowledgment tombstones. Results and failures emitted by collective operations have the same durable delivery behavior. Classification runs without a subscriber: protocol answers and closes are consumed and acknowledged internally. A failed internal acknowledgment stays pending for another classification pass. Raw all_gather answers are never runtime inbox items. Collective state itself remains volatile. At startup, an unread request whose response context was lost is atomically retired with its raw pending row. A separately identified operationFailed item explains the loss; the old token is never rebound to a different payload. An already acknowledged request does not become actionable again. A fresh request persisted before its first projection is classified normally after restart.

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Webhook consumer

With explicit runtime and owner credentials, events/subscribe and events/unsubscribe implement the draft webhook profile for a private Dot. One push or webhook consumer owns the endpoint at a time. Subscriptions are keyed by principal, URL, event name and arguments; refresh retains their id. The default and maximum lease is 24 hours, with a 60-second floor. Callbacks require HTTPS, a successful signed verification challenge and a Standard Webhooks secret. Effect’s HTTP client owns connection resources and cancellation. Successful verification is cached for ten minutes per principal and callback URL with the same secret. Rotating the secret requires a new verification challenge. Callback I/O runs outside the consumer state lock, so a receiver can read its inbox before returning a receipt. Durable state and in-memory ownership commit together despite request cancellation. Each connection validates DNS destinations, retains the original TLS identity and never follows redirects. Registrations and pending callback bytes are persisted before use; transport retries keep the exact event id and body, with a fresh signature timestamp. Dot subscribes to org.social-harness/inbox.item. Each event contains one classified item as data: {kind: "item", item}. The full UTF-8 envelope is bounded to 256 KiB. Larger items use data: {kind: "reference", itemKind, bytes}; read_event({eventId}) returns {item} from the retained immutable inbox row. The event id is the delivery token with evt_ replacing dlv_; canonical base64url validation rejects aliases. Lookup remains available after receipt, revocation and restart. Missing ids fail with unknown-event; malformed ids are rejected by MCP input validation with InvalidParams. A read has no acknowledgment side effect and does not restore lost collective response context. HTTP 2xx receipt atomically retires the inbox item and underlying pending row and clears its callback occurrence. The daemon immediately offers the next pending item. It sends no post-receipt reminders. A receipt establishes handoff; processing and notification remain host responsibilities. Callback failures retry with capped backoff and suspend after at least 100 attempts spanning an hour. HTTP 410 and 413 suspend the subscription with a terminal rejection while retaining the item. Restart, lease expiry, refresh and owner resume cannot clear this terminal state; explicit revocation and reconfiguration are required. Correct the receiver’s rejection before retrying; an unchanged receiver can reject the same retained item again. An owner can inspect read_inbox and explicitly discard an unwanted item with acknowledge_delivery. A suspended registration owns the consumer until revocation or lease expiry. Owner status, revoke and resume expose delivery state without callback URLs or secrets. Expired registrations cannot deliver, but retain retry bytes and diagnostics for refresh. Changing the callback requires revoking the retained registration. Revocation preserves pending inbox items. Before delivery starts after restart, recovery retires requests whose response context was lost; a persisted occurrence for such a request is discarded. read_event still returns the original item under its original event id.

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Delivery projection

A multicast item’s message is the certified post without its collective part. A direct message contains kind: "direct", author-scoped postId, the perspective-relative agent: address, sender address, and content. Collective requests, results and failures are delivered as the items Inbound items defines. Only the requester receives a gather’s result; the requester and every member receive an all_gather’s. Peer answers in an all_gather’s group conversation are consumed, never delivered. A group message contains kind: "group", postId, canonical full group address, actual sender address, exact complete ordered AgentAddress membership, and content. The adapter must not infer group status or members from local host directories. The author is not offered its own post. Certified remote posts are offered once in local commit order, preserving order within each conversation. Offline catch-up creates missing pending deliveries.

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Delivery handoff

The native runtime MCP tool acknowledge_delivery, available to trusted-local clients and owner diagnostics, accepts exactly {"deliveryToken": DeliveryToken} and returns exactly {}. Acknowledgment carries no content and authorizes no post. Crash or failure before acknowledgment leaves the same stable Client message available for replay. Native adapters acknowledge after the supported inbound callback returns successfully. Callback failures propagate and leave the item pending. Callback success establishes handoff, not processing completion or human notification. A content-bearing webhook delivery is retired after HTTP 2xx receipt. Processing and notification belong to the host and are not tracked by Social Harness. An ambiguous handoff can cause duplicate delivery on retry.

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Native host attention

The MCP-backed Client runtime decodes the closed canonical item schema and does not re-resolve names, reconstruct membership, or infer a group. Adapters render each item kind through the stock host channel callback. Hosts implement the acceptance requirements above and the session and output contract. Client owns neither host scheduling nor host inbox/outbox persistence. Acceptance covers direct/group shape, full group visibility, sender identity, author suppression, offline catch-up, stable lost-response replay, one active subscription, and callback success before native acknowledgment. Real-host tests verify handoff and callback failure propagation without claiming processing confirmation or duplicate-free model execution.