Channel outbound API

Channel plugins expose outbound message behavior from openclaw/plugin-sdk/channel-outbound. Use openclaw/plugin-sdk/channel-inbound for receive/context/dispatch orchestration.

Core owns queueing, durability, the durable ingress monitor and drain (createChannelIngressMonitor, createChannelIngressDrain, and openChannelIngressDrain), generic retry policy, turn-adoption lifecycle (turnAdoptionLifecycle / bindIngressLifecycleToReplyOptions), hooks, receipts, and the shared message tool. The plugin owns native send/edit/delete calls, target normalization, platform threading, selected quotes, notification flags, account state, ingress inspection and payload encoding, lane keys, non-retryable predicates, optional supersede authorization, and platform-specific side effects.

Durable ingress monitors

Use createChannelIngressMonitor(...) when a channel must persist accepted transport events before dispatch. It composes a channel ingress queue and drain with the shared admission, polling, pruning, delivery, and shutdown lifecycle. Use the lower-level createChannelIngressDrain(...) only when the transport owns a materially different admission or pump contract.

The required options are:

The monitor serializes admissions so append backoff cannot invert a lane. The default bounded append delays are 0, 100, and 300 ms; exhaustion rejects the transport callback instead of dispatching an event that was not made durable. At claim time it decodes the versioned payload, re-runs inspect, and rejects an id or lane mismatch before delivery.

onDurableAdmission(raw, context) runs after every durable enqueue, including duplicates. context.isNew is true if and only if this admission inserted the (queue_name, event_id) row. It does not indicate claim ownership or eventual delivery. If retention previously pruned the row, a later admission may insert it again and report isNew: true.

deliver receives onAdopted, onDeferred, onAdoptionFinalizing, onFailed, onCancelled, onAbandoned, and abortSignal. Use onFailed for delivery errors, onCancelled for explicit pre-adoption cancellation that must preserve retry accounting, and onAbandoned when a non-adopted turn should consume a retry attempt. Returning without an explicit handoff marks a terminal no-dispatch event adopted. admission is always exclusive. A deferred handoff keeps the claim held, while shutdown or abort leaves unadopted work retryable. The monitor tracks delivery independently from claim settlement because adoption can tombstone a row before the channel's delivery promise returns.

One turn, several durable claims

A channel that answers several inbound events as one turn holds one durable claim per event, and every one of them has to reach a terminal disposition. fanInChannelIngressLifecycles(lifecycles), from openclaw/plugin-sdk/channel-ingress-runtime, returns a single ChannelIngressLifecycle that fans each callback out across all of them, plus settle, abandon, and cancel for the paths that finish outside a callback. Pass the events' lifecycles in the order they were claimed; undefined entries are skipped, and an empty input yields lifecycle: undefined so a caller can fall back to the single-claim path without branching. Adopting the combined lifecycle adopts every claim, and abandoning it returns every claim to its retry budget — no claim is left half-settled. Adoption runs in the order the claims were passed, and a claim whose adoption is rejected — the drain raises that when another owner has taken it — fails itself and every claim behind it while the claims already adopted stay adopted, so a rejection reaches the caller with nothing left held.

Use it only when one agent turn genuinely consumes several claims. A channel that answers each event on its own keeps passing that event's lifecycle directly.

Start slots and deferral

drain.startLimit bounds how many deliveries the drain starts at once. A delivery that defers normally keeps its slot, because a deferred delivery on the default deferredLaneOccupancy: "hold" still serializes its lane. A drain that declares deferredLaneOccupancy: "release" gives the lane up on deferral, so its deferred deliveries also give their start slot back, bounded by a budget equal to startLimit: open delivery callbacks stay within startLimit plus that budget, and past it a deferral keeps its slot. Without the release, a handful of deferred deliveries would hold every slot and stall the other lanes. How much handed-off deferred work may be pending at once stays the drain owner's semantics, unchanged by this budget.

Optional settings include custom append delays, a drain option block for advanced drain ordering/concurrency/retry policy, an external abortSignal, a clock, pump error reporting, a stopped-error factory, and admission policy. The returned monitor exposes admit, ensureQueueAvailable, start, pause, stop, waitForIdle, isRunning, and isStopped. Use the idempotent ensureQueueAvailable() check when plugin-owned migration or preparation must run after the queue opens but before the drain starts. stop first settles accepted admissions, then aborts and disposes the drain, waits for the pump and active deliveries, and disposes again to close the lazy-creation race.

Keep transport-specific redaction, raw-envelope validation, non-retryable classification, and persisted payload shape in the plugin. Webhook transports should acknowledge only after admit resolves; non-replay transports should surface durable append exhaustion rather than silently dispatching.

Adapter

Most plugins define one message adapter:

import {  defineChannelMessageAdapter,  createMessageReceiptFromOutboundResults,} from "openclaw/plugin-sdk/channel-outbound"; export const demoMessageAdapter = defineChannelMessageAdapter({  id: "demo",  durableFinal: {    capabilities: {      text: true,      replyTo: true,      thread: true,      messageSendingHooks: true,    },  },  send: {    text: async ({ cfg, to, text, accountId, replyToId, threadId, signal }) => {      const sent = await sendDemoMessage({        cfg,        to,        text,        accountId: accountId ?? undefined,        replyToId: replyToId ?? undefined,        threadId: threadId == null ? undefined : String(threadId),        signal,      });       return {        receipt: createMessageReceiptFromOutboundResults({          results: [{ channel: "demo", messageId: sent.id, conversationId: to }],          kind: "text",          threadId: threadId == null ? undefined : String(threadId),          replyToId: replyToId ?? undefined,        }),      };    },  },});

Only declare capabilities the native transport actually preserves. Cover each declared capability with the matching contract helper exported from this subpath:

• send: verifyChannelMessageAdapterCapabilityProofs(...)
• durable final delivery: verifyDurableFinalCapabilityProofs(...)
• live preview: verifyChannelMessageLiveCapabilityAdapterProofs(...) and verifyChannelMessageLiveFinalizerProofs(...)
• receive ack: verifyChannelMessageReceiveAckPolicyAdapterProofs(...)

Outbound echo suppression

When a platform may redeliver the plugin's own outbound message as inbound, call recordOutboundMessageIdentity(...) with the channel, account, conversation, and a stable platform message or source identity. The shared inbound turn path drops matching identities for a bounded 30-second window before session recording or agent dispatch; a source identity may be reserved before send or refreshed when a channel route is removed to close delivery races. isRecentOutboundMessageIdentity(...) exposes the same query for channel diagnostics and tests. Do not maintain a parallel channel-local TTL cache for the same stable identity.

Plain-text sanitization

Use sanitizeForPlainText(...) when an outbound adapter needs to convert the supported HTML formatting tags into lightweight text markup. The default keeps the existing chat-style bold and strikethrough markers. Pass { style: "markdown" } only when the channel reparses the result as Markdown:

import { sanitizeForPlainText } from "openclaw/plugin-sdk/channel-outbound"; const chatText = sanitizeForPlainText(text);const markdownText = sanitizeForPlainText(text, { style: "markdown" });

The Markdown style uses **bold** and ~~strikethrough~~; italic and inline code keep _italic_ and backtick markers in both styles. Select the style at the channel boundary instead of rewriting marker text after sanitization.

Delivery Evidence

A MessageReceipt records the result returned by a channel adapter. Concrete platform message identifiers show that the platform send path accepted the message; they do not prove that a recipient's device displayed or read it. Destination and routing identifiers such as chat, channel, room, conversation, or recipient JID are metadata, never platformMessageIds. Receipts without platform message identifiers are local receipt metadata only. A provider-observed receipt thread overrides the requested route thread. If a batch contains conflicting provider threads, each part retains its thread and the aggregate receipt omits threadId. Channels with read receipts or device-delivery state should track those facts through a separate channel-specific path.

When an adapter intentionally omits a send before dispatch, return outcome: "not_sent" with an empty receipt and no message ID (legacy outbound adapters use an empty messageId). Core records adapter_returned_no_send as an intentional suppression, counts no physical send, and skips send-success and commit hooks. Do not use this outcome for an acknowledged send without a platform ID or for an unknown result after dispatch. An empty receipt alone does not distinguish those states; existing acknowledgement behavior is unchanged when outcome is omitted.

If a channel adapter can prove that retrying a failure cannot duplicate a recipient-visible send and no finalization-capable call began, throw new PlatformMessageNotDispatchedError("...", { cause: error }) from openclaw/plugin-sdk/error-runtime. Core can then clear stale send-attempt evidence and safely retry the queued intent. Only the adapter that owns the final dispatch boundary may make this assertion. Never use the marker after a finalization/send call begins or returns an ambiguous result; false marking can duplicate messages.

Existing outbound adapters

If the channel already has a compatible outbound adapter, derive the message adapter instead of duplicating send code:

import { createChannelMessageAdapterFromOutbound } from "openclaw/plugin-sdk/channel-outbound"; export const messageAdapter = createChannelMessageAdapterFromOutbound({  id: "demo",  outbound,  durableFinal: {    capabilities: {      text: true,      media: true,    },  },});

Deriving an adapter does not make a channel-owned prepared dispatcher durable. Route its final sends through the durable helpers while preserving channel-specific post-send effects and callback-only transport targets. message.send.lifecycle.afterSendSuccess runs after the native send succeeds; for queued sends, afterCommit runs after queue acknowledgment. Keep effects at the boundary they require rather than leaving them only in a legacy dispatcher.

Durable sends

Runtime send helpers also live on channel-outbound:

• sendDurableMessageBatch(...)
• withDurableMessageSendContext(...)
• deliverInboundReplyWithMessageSendContext(...)
• draft streaming/progress helpers such as resolveChannelDraftStreamingChunking(...)

sendDurableMessageBatch(...) and withDurableMessageSendContext(...) default to durability: "required": failure to persist the send intent stops delivery before the platform call. With durability: "best_effort", a queue-write failure can fall through to a logged, live-only send without crash recovery. These durable helpers do not accept durability: "disabled".

sendDurableMessageBatch(...) returns one explicit outcome:

Use payloadOutcomes when a batch mixes sent, suppressed, and failed payloads. Do not infer hook cancellation from an empty legacy direct-delivery result.

A suppressed result is ambiguous when its reason is adapter_returned_no_identity, or any payload outcome records a send, an identityless send, or a failure with sentBeforeError. Check the whole batch before treating suppression as intentional non-delivery. For a known omission, an action can return { status: "suppressed", reason: result.reason } without a tool error or a fabricated receipt. Keep free-form hook diagnostics private. Suppression does not recover an earlier failed send.

Failure is not permission to send the same payload through another path. Once admitted, the queue owns retry or reconciliation until its exact owner acknowledges or terminally retires the intent. Pending custody is not a delivery receipt: preserve partial receipts, and do not report an unconfirmed ask_user prompt as visible. Gateway OUTBOUND_DELIVERY_QUEUED responses mean delivery is pending and must not be resent; an ambiguous send may need reconciliation rather than an automatic retry.

When a transport creates a thread during its first successful send, the outbound adapter may implement adoptTargetFromDelivery(...). Return the typed thread ID from the platform receipt and core carries it into later payloads, pins, and post-delivery hooks in that durable batch. Core never replaces an explicit caller thread, and it does not infer adoption from receipt.threadId without the adapter opt-in.

Automatic unknown-send reconciliation

Set message.durableFinal.automaticUnknownSendReconciliation only when the plugin can reconcile an ambiguous provider send from persisted, post-policy state without rerunning modifying hooks or regenerating provider payloads. Core considers this opt-in after hooks and cancellation, and only for exactly one accepted prepared payload. Multi-payload batches do not opt in automatically.

The adapter must also advertise capabilities.reconcileUnknownSend: true and provide reconcileUnknownSend(...). Use reconcileUnknownSendKinds to name the concrete transport branches the plugin can prove, such as text or media. If the kind map is present, the selected branch must be true. Omitting the map means the callback claims every selected branch, so prefer an explicit map for new plugins.

The callback must use provider-owned idempotency or authoritative readback to return sent with the actual provider receipt, not_sent only when a fresh send is provably safe, or unresolved when neither outcome can be proven. When reconciliation is explicitly required, unsupported prepared shapes fail before provider I/O. During recovery, missing, incomplete, or mismatched provider proof must fail closed rather than replaying content that could already be visible.

If reconciliation needs provider-owned persisted evidence, implement afterUnknownSendTerminal(...). Core calls it after the ambiguous queue row has authoritatively moved to failed, including retry-budget exhaustion. Use it to remove provider-owned plans or payloads that are no longer needed. Cleanup is best effort and must be idempotent; a failure is logged without making the terminal queue row replayable again.

Deferred delivery admission

Use message.durableFinal.admitDeferredDelivery(...) when a resolved account cannot safely accept core-managed outbound or deferred delivery. Core calls this hook synchronously before live outbound work, including paths that skip queue persistence, and again before replaying a recovered intent. The context includes cfg, channel, to, accountId, and a phase of live or recovery.

Return { status: "allowed" } to continue. Return { status: "permanent_rejection", reason } when the delivery must not be persisted, sent directly, or replayed. A live rejection fails before queue creation, message hooks, or platform work. A recovery rejection marks the queued record failed and skips reconciliation and replay. Omitting the hook means allowed.

The hook is a synchronous admission decision, not a send path. Read only already-loaded config or runtime state; do not perform network, filesystem, or other asynchronous I/O. Contract tests should exercise both phases and both result variants through ChannelMessageDurableFinalAdapter from openclaw/plugin-sdk/channel-outbound.

Compatibility dispatch

Assemble inbound reply dispatch through dispatchChannelInboundReply(...) from channel-inbound. Keep platform delivery in the delivery adapter; use channel-outbound for message adapters, durable sends, receipts, live preview, and reply pipeline options.

Migrating from channel-message

openclaw/plugin-sdk/channel-message is a deprecated compatibility entrypoint. It still re-exports channel-outbound and preserves three dispatch aliases. Migrate those aliases to openclaw/plugin-sdk/channel-inbound:

Follow the dated removal-eligibility window in Migration. This subpath is not tied to the next Plugin SDK major, and eligibility does not itself remove an export. External imports do not emit a runtime warning; update plugin imports rather than waiting for one.

Related

• Channel inbound API — the receive side that records and dispatches before a reply is sent
• Channel ingress API — the resolver that produces the participant identity a send is attributed to
• Building channel plugins — the full channel plugin walkthrough
• Plugin SDK subpaths — which subpath exports each helper
• Plugin SDK migration — removal-eligibility windows for legacy outbound exports