qwen-code/docs/developers/daemon/09-event-schema.md

Typed Daemon Event Schema v1

Overview

Every SSE frame emitted by the daemon on GET /session/:id/events has the shape { id, v, type, data, originatorClientId?, _meta? }. v: 1 is the current EVENT_SCHEMA_VERSION. type comes from the closed, version-pinned DAEMON_KNOWN_EVENT_TYPE_VALUES set in packages/sdk-typescript/src/daemon/events.ts; the current set has 43 known event types. The envelope _meta field is stamped at the SSE write boundary by formatSseFrame() in server.ts; see Envelope-level metadata.

The SDK exposes asKnownDaemonEvent(evt). It returns a discriminated KnownDaemonEvent for known event types and undefined for other types. SDK consumers can therefore handle forward compatibility without requiring a lockstep SDK upgrade when a newer daemon adds an event type; the session reducer records those as unrecognizedKnownEventCount.

The wire format lives in ../qwen-serve-protocol.md. This page is the payload contract for each event.

Responsibilities

• Provide the single source of truth for the event vocabulary (DAEMON_KNOWN_EVENT_TYPE_VALUES).
• Provide a typed envelope for each event type (DaemonEventEnvelope<TType, TData>).
• Provide pure reducers (reduceDaemonSessionEvent, reduceDaemonAuthEvent) that project an event stream into SDK view state.
• Broadcast the typed_event_schema capability tag as an informational signal. If the tag is absent, asKnownDaemonEvent still falls back to unknown.

Event vocabulary (43 known types)

Grouped by domain.

Core session

Type	Direction	Trigger	Key payload fields
session_update	S->C	Any ACP sessionUpdate notification: agent text, thought, tool call, or plan	sessionUpdate: string, content?: ... (opaque ACP shape)
session_metadata_updated	S->C	PATCH /session/:id/metadata	sessionId, displayName?
session_died	S->C terminal	channel.exited	sessionId, reason, exitCode? | null, signalCode? | null
session_closed	S->C terminal	DELETE /session/:id or programmatic close	sessionId, reason: 'client_close' | string, closedBy?
session_snapshot	S->C synthetic	Snapshot frame after SSE attach / replay	sessionId, currentModelId: string | null, currentApprovalMode: string | null

Subscriber-level synthetic frames

Type	Trigger	Notes
client_evicted	Per-subscriber EventBus queue overflow. No id	reason: string, droppedAfter?: number; terminal only for the current subscriber, while the session remains alive.
slow_client_warning	Queue >= 75%; force-pushed and has no id	queueSize, maxQueued, lastEventId; re-armed after the queue drops below 37.5%.
stream_error	SubscriberLimitExceededError or another route stream error	error: string; terminal for the subscription.
state_resync_required	subscribe({lastEventId}) detects that the daemon ring no longer holds [lastEventId+1, earliestInRing-1], or the client cursor is from a previous bus epoch. Force-pushed before remaining replay frames and has no id.	reason: 'ring_evicted' | 'epoch_reset' | string, lastDeliveredId: number, earliestAvailableId: number. This is a recovery signal, not terminal: the SSE stream stays open and replay + live frames continue. The SDK reducer sets awaitingResync = true and skips deltas until the caller resets with loadSession.
replay_complete	Id-less sentinel emitted after the Last-Event-ID replay loop finishes, for both clean replay and ring-evicted paths, even when data.replayedCount === 0. No id	replayedCount: number; lets consumers remove catch-up UI deterministically without a timeout.

Permissions (F3 + base)

Type	Direction	Trigger	Key payload fields
permission_request	S->C	Agent calls requestPermission	requestId, sessionId, toolCall, options[]; the envelope stamps originatorClientId from the prompt originator.
permission_resolved	S->C	Mediator has decided	requestId, outcome (ACP PermissionOutcome)
permission_already_resolved	S->C	Vote arrives after the request was already decided	requestId, sessionId, outcome
permission_partial_vote	S->C	consensus policy records a non-final vote	requestId, sessionId, votesReceived, votesNeeded (>= 1), quorum, optionTallies: Record<string, number>, originatorClientId?
permission_forbidden	S->C	Policy rejects a vote	requestId, sessionId, clientId?, reason: 'designated_mismatch' | 'remote_not_allowed', originatorClientId?; anonymous voters omit clientId.

Models

Type	Direction	Payload
model_switched	S->C	sessionId, modelId
model_switch_failed	S->C	sessionId, requestedModelId, error: string

MCP guardrails (PR 14b + F2)

Type	Direction	Payload
mcp_budget_warning	S->C	liveCount, reservedCount, budget, thresholdRatio: 0.75, mode: 'warn' | 'enforce', scope?: 'workspace' | 'session'
mcp_child_refused_batch	S->C	refusedServers: [{ name, transport, reason: 'budget_exhausted' }], budget, liveCount, reservedCount, mode: 'enforce', scope?: 'workspace' | 'session'
mcp_server_restarted	S->C	serverName, durationMs, entryIndex? for F2 multi-entry pool restarts
mcp_server_restart_refused	S->C	serverName, reason: 'budget_would_exceed' | 'in_flight' | 'disabled' | 'restart_failed', entryIndex?, details?. The fourth value, restart_failed, carries an underlying hard failure for pool-mode multi-entry restart. MCP_RESTART_REFUSED_REASONS rejects unknown reasons; an older SDK reducer silently drops additive new reason values because parseDaemonEvent returns undefined. Ship a new reason with an SDK that knows it.

Mutation control (Wave 4 PR 16+17)

Type	Direction	Payload
memory_changed	S->C	scope: 'workspace' | 'global', filePath, mode: 'append' | 'replace', bytesWritten
agent_changed	S->C	change: 'created' | 'updated' | 'deleted', name, level: 'project' | 'user'
approval_mode_changed	S->C	sessionId, previous, next, persisted: boolean
tool_toggled	S->C	toolName, enabled; affects the next ACP child spawn and does not mutate already-running sessions.
settings_changed	S->C	Workspace settings write completed. Payload is open; consumers should refresh with read-after-write.
settings_reloaded	S->C	Daemon workspace service reread settings. Payload is open.
workspace_initialized	S->C	path, action: 'created' | 'overwrote' | 'noop', originatorClientId?

Auth device flow (PR 21)

These events are workspace-keyed, not session-keyed. The session reducer treats them as no-ops; reduceDaemonAuthEvent projects them into workspace-level state.

Type	Direction	Payload
auth_device_flow_started	S->C	deviceFlowId, providerId, expiresAt
auth_device_flow_throttled	S->C	deviceFlowId, intervalMs
auth_device_flow_authorized	S->C	deviceFlowId, providerId, expiresAt?, accountAlias?
auth_device_flow_failed	S->C	deviceFlowId, errorKind, hint?
auth_device_flow_cancelled	S->C	deviceFlowId

MCP runtime mutation

Type	Direction	Trigger	Key payload fields
mcp_server_added	S->C	Server added at runtime through POST /workspace/mcp/servers	name, transport, replaced, shadowedSettings, toolCount, originatorClientId
mcp_server_removed	S->C	Server removed at runtime	name, wasShadowingSettings, originatorClientId

Turn lifecycle / assistant pushes

Type	Direction	Trigger	Key payload fields
prompt_cancelled	S->C	Prompt was cancelled through explicit cancelSession route or originator SSE disconnect	Envelope stamps originatorClientId for the canceling client. This means "cancellation requested", not "cancellation confirmed". Peer subscribers learn that the prompt has ended.
turn_complete	S->C	A turn completed successfully	sessionId, stopReason, promptId?. promptId links to non-blocking prompt responses (202). The SDK matches SSE events to the originating prompt through it.
turn_error	S->C	A turn failed	sessionId, message, code?, promptId?; same promptId correlation mechanism.
session_rewound	S->C	POST /session/:id/rewind succeeded	sessionId, promptId, targetTurnIndex, filesChanged[], filesFailed[], originatorClientId?
session_branched	S->C	POST /session/:id/branch created a branch from an existing session	sourceSessionId, newSessionId, displayName, originatorClientId?
followup_suggestion	S->C	ACP child generated ghost-text follow-up suggestions after end_turn, forwarded over per-session SSE	sessionId, suggestion, promptId; wire only carries suggestions whose getFilterReason()===null. Clients render them as input-placeholder ghost text and invalidate them on next sendPrompt.
user_shell_command	S->C	User started a shell command through POST /session/:id/shell; fanned out to other subscribers in the same session	sessionId, command, shellId, originatorClientId?. There is no typed DaemonXxxData interface yet; asKnownDaemonEvent returns undefined and the UI normalizer parses it ad hoc.
user_shell_result	S->C	Result of the shell command above	sessionId, shellId, exitCode, output, aborted. Same ad hoc parsing note as user_shell_command.

Architecture

Concern	Source	Notes
EVENT_SCHEMA_VERSION = 1	packages/acp-bridge/src/eventBus.ts	Sent on every frame.
DAEMON_KNOWN_EVENT_TYPE_VALUES	packages/sdk-typescript/src/daemon/events.ts	Closed list with 43 types.
DaemonEventEnvelope<TType, TData>	events.ts	Generic envelope.
DaemonKnownEventType	events.ts	typeof DAEMON_KNOWN_EVENT_TYPE_VALUES[number].
Per-event payload types	events.ts	Most event types have a DaemonXxxData interface; user_shell_* is currently parsed ad hoc by the UI normalizer.
asKnownDaemonEvent(evt)	events.ts	Returns KnownDaemonEvent | undefined.
reduceDaemonSessionEvent(state, evt)	events.ts	Projects into DaemonSessionViewState.
reduceDaemonAuthEvent(state, evt)	events.ts	Projects into DaemonAuthState.
isWorkspaceScopedBudgetEvent(evt)	events.ts	Detects F2 scope: 'workspace'.

DaemonSessionViewState

reduceDaemonSessionEvent fills this view state. CLI TUI adapter, DaemonChannelBridge, and VS Code IDE consume it. Key fields:

• alive: boolean - becomes false after a terminal frame (session_died, session_closed, client_evicted, stream_error).
• currentModelId?: string - from model_switched.
• displayName?: string - from session_metadata_updated.
• pendingPermissions: Record<string, DaemonPermissionRequestData> - open requests keyed by requestId; cleared by permission_resolved / permission_already_resolved.
• lastSessionUpdate?: DaemonSessionUpdateData - latest session_update.
• lastModelSwitchFailure?: DaemonModelSwitchFailedData - from model_switch_failed.
• terminalEvent? - raw terminal event.
• streamError?: DaemonStreamErrorData - latest stream_error payload.
• unrecognizedKnownEventCount, lastUnrecognizedKnownEvent? - event was recognized by asKnownDaemonEvent but the reducer has no dedicated state for it yet.
• droppedPermissionRequestCount, lastDroppedPermissionRequestId? - malformed permission request could not enter the pending map.
• unmatchedPermissionResolutionCount, lastUnmatchedPermissionResolutionId? - permission resolution had no matching pending request.
• slowClientWarningCount, lastSlowClientWarning? - from slow_client_warning.
• mcpBudgetWarningCount, lastMcpBudgetWarning? - from mcp_budget_warning.
• mcpChildRefusedBatchCount, lastMcpChildRefusedBatch? - from mcp_child_refused_batch.
• lastWorkspaceMutation?, lastWorkspaceMutationType? - from memory_changed / agent_changed.
• approvalMode?, approvalModeChangedCount, lastApprovalModeChange? - from approval_mode_changed.
• toolToggleCount, lastToolToggle? - from tool_toggled.
• workspaceInitCount, lastWorkspaceInit? - from workspace_initialized.
• mcpRestartCount, lastMcpRestart? - from mcp_server_restarted.
• mcpRestartRefusedCount, lastMcpRestartRefused? - from mcp_server_restart_refused.
• settings_changed / settings_reloaded - recognized by asKnownDaemonEvent; the session reducer does not maintain dedicated view-state fields, and UIs usually treat them as refresh signals.
• permissionVoteProgress: Record<string, DaemonPermissionPartialVoteData> - consensus voting progress.
• forbiddenVotes: DaemonPermissionForbiddenData[], forbiddenVoteCount - policy-rejected vote records, capped at 32.
• awaitingResync: boolean - set by state_resync_required; cleared when consumer resets view state.
• resyncRequiredCount, lastResyncRequired? - resync observability.
• lastFollowupSuggestion?: DaemonFollowupSuggestionData - latest follow-up suggestion pushed by daemon.
• lastTurnComplete?: DaemonTurnCompleteData - latest successful turn completion.
• lastTurnError?: DaemonTurnErrorData - latest turn error.
• rewindCount, lastRewind?, lastBranch? - latest rewind / branch events.

DaemonAuthState

One entry per providerId, driven by auth_device_flow_*. Each flow exposes { deviceFlowId, status, providerId, expiresAt?, lastThrottleIntervalMs?, lastError? }.

Flow

Producer side

flowchart LR
    A["ACP child notification"] --> B["BridgeClient.sessionUpdate /<br/>BridgeClient.extNotification"]
    B --> C{"Mapped to event type?"}
    C -->|yes| D["EventBus.publish({type, data, originatorClientId?})"]
    C -->|no| E["No emit (drop or log)"]
    D --> F["Assign id + v=1, push to ring"]
    F --> G["Fan out to all subscribers"]

Consumer side (SDK)

flowchart LR
    A["SSE bytes"] --> B["parseSseStream -> DaemonEvent[]"]
    B --> C["asKnownDaemonEvent(evt)"]
    C -->|"KnownDaemonEvent"| D["reduceDaemonSessionEvent(state, evt)"]
    C -->|"auth_device_flow_*"| E["reduceDaemonAuthEvent(state, evt)"]
    C -->|"undefined"| F["unrecognizedKnownEventCount++<br/>(forward-compat)"]

Envelope-level metadata

Beyond each event's data payload, the daemon stamps two envelope-level fields.

_meta.serverTimestamp - daemon clock

formatSseFrame() in packages/cli/src/serve/server.ts stamps this at the SSE write boundary, not inside EventBus.publish. The in-memory BridgeEvent type stays unchanged; internal daemon consumers do not see _meta, while wire SSE frames do.

{
  "id": 47,
  "v": 1,
  "type": "session_update",
  "data": { ... },
  "_meta": { "serverTimestamp": 1716287345123 }
}

The merge preserves any existing _meta keys ({...existingMeta, serverTimestamp: Date.now()}). No current daemon producer writes envelope-level _meta. The top-level merge is a forward-compatibility escape hatch.

Why it matters: multi-client UIs that render relative time or sort transcript blocks should use server time instead of each browser/tab/phone local clock. Server stamping keeps ordering consistent across clients.

SDK access: prefer event._meta?.serverTimestamp. Compatibility paths may also probe event.serverTimestamp or event.data._meta.serverTimestamp. Do not mix ACP payload data._meta with daemon envelope _meta.

originatorClientId

Events triggered by a request that carried a registered X-Qwen-Client-Id may stamp this field. See 08-session-lifecycle.md.

Tool-call _meta (provenance / serverId)

This is separate from envelope _meta: ACP session/update payloads can carry their own _meta in event.data._meta. ToolCallEmitter (packages/cli/src/acp-integration/session/emitters/ToolCallEmitter.ts) stamps two fields on emitStart, emitResult, and emitError:

Field	Type	Resolution rule
provenance	'builtin' | 'mcp' | 'subagent'	ToolCallEmitter.resolveToolProvenance: subagentMeta wins with subagent; tool name matching mcp__<server>__<tool> maps to mcp; everything else maps to builtin.
serverId	string only when provenance === 'mcp'	Extracted heuristically from mcp__<serverId>__<tool>.

The existing _meta.toolName display name is preserved. UI uses these fields to render builtin / MCP server / subagent badges without reparsing the tool name.

SDK reducer behavior

reduceDaemonSessionEvent(state, evt) in packages/sdk-typescript/src/daemon/events.ts projects the stream into DaemonSessionViewState. The resync-related fields are:

• awaitingResync: boolean - set by state_resync_required; caller clears it, typically after POST /session/:id/load resets view state.
• resyncRequiredCount: number - observability counter.
• lastResyncRequired?: DaemonStateResyncRequiredData - latest payload.

While awaitingResync = true, the reducer skips delta application and only allows the closed RESYNC_PASSTHROUGH_TYPES set:

Passthrough type	Why it is still applied during resync
state_resync_required	Rare second resync should update lastResyncRequired / resyncRequiredCount.
session_died	Terminal stream signal must remain visible during resync.
session_closed	Same as above.
client_evicted	Same as above.
stream_error	Same as above.
session_snapshot	Full-state authoritative frame; safe to apply during resync.

lastEventId still advances monotonically through advanceLastEventId(base) during resync. After the caller resets and clears awaitingResync, subsequent deltas align to the correct cursor.

reduceDaemonAuthEvent projects device-flow events into workspace-level auth state entries shaped like {deviceFlowId, status, providerId, expiresAt?, lastThrottleIntervalMs?, lastError?} conceptually. In code the reducer stores status, errorKind, hint, intervalMs, lastSeenEventId, authorizedExpiresAt, and accountAlias on DaemonDeviceFlowReducerState; the daemon event payloads themselves remain the per-event shapes listed above.

State and forward compatibility

• Add a known event type by appending to DAEMON_KNOWN_EVENT_TYPE_VALUES. Old SDKs return undefined for unrecognized event types through the fallback path and increment unrecognizedKnownEventCount; new SDKs rely on the discriminated union.
• Adding optional fields to an existing payload is safe because payloads are open ({ [key: string]: unknown }).
• Changing an existing payload shape is breaking and must bump EVENT_SCHEMA_VERSION plus advertise a compatible capability tag such as caps.features.typed_event_schema_v2.
• id is per-session monotonic. Subscriber-level synthetic frames (client_evicted, slow_client_warning, stream_error, state_resync_required, replay_complete, session_snapshot) intentionally have no id so other subscribers do not see gaps.
• originatorClientId lives on the envelope rather than data. F3 partial-vote / forbidden payloads also merge it into data through mergeOriginator so view-state consumers do not need to retain the envelope.

Dependencies

• 10-event-bus.md - delivery channel.
• 11-capabilities-versioning.md - how SDKs preflight typed_event_schema, mcp_guardrail_events, and permission_mediation.
• 04-permission-mediation.md - how permission events are produced.
• 13-sdk-daemon-client.md - asKnownDaemonEvent, reducers, and view-state shape.

Configuration

• Always advertised: typed_event_schema, mcp_guardrail_events, and permission_mediation (with supported policy modes).
• No env var or flag directly controls the schema itself. QWEN_SERVE_NO_MCP_POOL=1 changes MCP event scope from 'workspace' to absent or 'session'.

Caveats and known limits

• Six synthetic frame types intentionally have no id; SDK code must not assume every event has an id.
• permission_partial_vote only appears under consensus. permission_forbidden appears under designated, consensus, and local-only, but not under first-responder.
• mcp_child_refused_batch only appears in mode: 'enforce'; warn mode never refuses.
• auth_device_flow_* events are not session-keyed. When consuming through DaemonSessionClient, use reduceDaemonAuthEvent for them rather than the session reducer.

References

• packages/sdk-typescript/src/daemon/events.ts
• packages/acp-bridge/src/eventBus.ts (EVENT_SCHEMA_VERSION)
• packages/cli/src/serve/capabilities.ts (typed_event_schema, mcp_guardrail_events, permission_mediation)
• Wire reference: ../qwen-serve-protocol.md