feat: add agent response scheduler

2026-07-02 22:31:14 +01:00 · 2026-07-01 23:50:38 +01:00
parent 952f8e4fb0
commit af4df2cd2c
33 changed files with 1690 additions and 505 deletions
--- a/apps/agent-test-cli/package.json
+++ b/apps/agent-test-cli/package.json
@@ -10,6 +10,6 @@
 	},
 	"dependencies": {
 		"@freya/agent-protocol": "workspace:*",
-		"@nym.sh/jrpc": "^0.1.0"
+		"@nym.sh/jrpc": "1.1.0"
 	}
 }
--- a/apps/freya-backend/package.json
+++ b/apps/freya-backend/package.json
@@ -26,7 +26,7 @@
 		"@freya/source-tfl": "workspace:*",
 		"@freya/source-weatherkit": "workspace:*",
 		"@freya/source-web-search": "workspace:*",
-		"@nym.sh/jrpc": "^0.1.0",
+		"@nym.sh/jrpc": "1.1.0",
 		"@openrouter/sdk": "^0.9.11",
 		"arktype": "^2.1.29",
 		"better-auth": "^1",
--- a/apps/freya-backend/src/admin/http.test.ts
+++ b/apps/freya-backend/src/admin/http.test.ts
@@ -44,7 +44,7 @@ mock.module("../sources/user-sources.ts", () => ({
 	}),
 }))

-mock.module("../conversations/storage.ts", () => ({
+mock.module("../conversations/db-storage.ts", () => ({
 	conversations: (_db: Database, userId: string) => ({
 		async getOrCreateConversation() {
 			return { id: `conversation-${userId}` }
--- a/apps/freya-backend/src/agent/job.ts
+++ b/apps/freya-backend/src/agent/job.ts
@@ -0,0 +1,145 @@
+import type { AgentEvent } from "@freya/agent-protocol"
+
+import {
+	AssistantMessagePayload,
+	ConversationEntryKind,
+	UserMessagePayload,
+	ToolCallPayload,
+	ToolResultPayload,
+} from "@freya/core"
+import { type } from "arktype"
+
+import type { ConversationStorage } from "../conversations/storage"
+import type { Job } from "../lib/job"
+import type { JobExecutor } from "../lib/worker"
+import type { NotificationCentral } from "../notification/notification-central"
+import type { UserSessionManager } from "../session"
+
+import { ConversationResponseStateStatus } from "../db/schema"
+import { streamAgentResponse } from "./streaming"
+
+export interface AgentResponseJobPayload {
+	conversationId: string
+}
+
+interface AgentResponseWorkerConfig {
+	conversationStorage: ConversationStorage
+	userSessionManager: UserSessionManager
+	notificationCentral: NotificationCentral
+}
+
+export class AgentResponseJobExecutor implements JobExecutor<AgentResponseJobPayload> {
+	private conversationStorage: ConversationStorage
+	private userSessionManager: UserSessionManager
+	private notificationCentral: NotificationCentral
+
+	constructor({
+		conversationStorage,
+		userSessionManager,
+		notificationCentral,
+	}: AgentResponseWorkerConfig) {
+		this.conversationStorage = conversationStorage
+		this.userSessionManager = userSessionManager
+		this.notificationCentral = notificationCentral
+	}
+
+	async execute(job: Job<AgentResponseJobPayload>): Promise<void> {
+		const conversation = await this.conversationStorage.findConversation(job.payload.conversationId)
+		if (!conversation) {
+			return
+		}
+
+		const claimed = await this.conversationStorage.claimPendingConversationResponseState(
+			job.payload.conversationId,
+		)
+		if (!claimed) {
+			// conversation response state not found or already claimed
+			return
+		}
+
+		const pendingEntries = await this.conversationStorage.listPendingUserConversationEntries(
+			conversation.userId,
+			conversation.id,
+		)
+		if (pendingEntries.length === 0) {
+			await this.conversationStorage.clearConversationResponseState(job.payload.conversationId)
+			return
+		}
+
+		const message = pendingEntries.reduce((acc, entry) => {
+			const payload = UserMessagePayload(entry.payload)
+			if (payload instanceof type.errors) {
+				return acc
+			}
+			return (
+				acc + "\n" + payload.parts.reduce((msg, p) => (p.type === "text" ? msg + p.text : msg), "")
+			)
+		}, "")
+
+		const session = await this.userSessionManager.getOrCreate(conversation.userId)
+
+		try {
+			for await (const event of streamAgentResponse({
+				agent: session.agent,
+				input: { message, signal: job.signal },
+			})) {
+				if (job.signal.aborted) {
+					break
+				}
+
+				await this.recordAgentEvent(event, conversation.id)
+				await this.notificationCentral.notifyUser(conversation.userId, {
+					kind: "agent",
+					payload: event,
+				})
+			}
+
+			// if job is aborted, stop everything immediately, including clean up.
+			// the aborter is assumed responsibility on how to proceed.
+			if (!job.signal.aborted) {
+				await this.conversationStorage.clearConversationResponseState(job.payload.conversationId)
+			}
+		} catch (err) {
+			console.error("[agent job executor] error streaming agent response:", err)
+			if (!job.signal.aborted) {
+				await this.conversationStorage.markResponseStateStatus(
+					[job.payload.conversationId],
+					ConversationResponseStateStatus.Failed,
+				)
+			}
+		}
+	}
+
+	private async recordAgentEvent(event: AgentEvent, conversationId: string) {
+		switch (event.type) {
+			case "message_created":
+				await this.conversationStorage.appendEntry(conversationId, {
+					kind: ConversationEntryKind.AssistantMessage,
+					payload: {
+						role: "assistant",
+						parts: [{ type: "text", text: event.text }],
+					} satisfies AssistantMessagePayload,
+				})
+				break
+
+			case "tool_started":
+				await this.conversationStorage.appendEntry(conversationId, {
+					kind: ConversationEntryKind.ToolCall,
+					payload: {
+						toolName: event.toolName,
+					} satisfies ToolCallPayload,
+				})
+				break
+
+			case "tool_finished":
+				await this.conversationStorage.appendEntry(conversationId, {
+					kind: ConversationEntryKind.ToolResult,
+					payload: {
+						toolName: event.toolName,
+						ok: event.ok,
+					} satisfies ToolResultPayload,
+				})
+				break
+		}
+	}
+}
--- a/apps/freya-backend/src/agent/pi-query-agent.ts
+++ b/apps/freya-backend/src/agent/pi-query-agent.ts
@@ -166,6 +166,16 @@ export class PiQueryAgent implements QueryAgent {
 			this.handlePiEvent(event, pushRunEvent)
 		})

+		input.signal?.addEventListener(
+			"abort",
+			async () => {
+				await session.abort()
+				close()
+				unsubscribe()
+			},
+			{ once: true },
+		)
+
 		session
 			.prompt(input.message)
 			.then(() => {
--- a/apps/freya-backend/src/agent/query-agent.ts
+++ b/apps/freya-backend/src/agent/query-agent.ts
@@ -2,6 +2,7 @@ export interface QueryAgentAsk {
 	message: string
 	conversationId?: string
 	userMessageEntry?: QueryAgentConversationEntryRef
+	signal?: AbortSignal
 }

 export type QueryAgentStreamEvent =
--- a/apps/freya-backend/src/agent/reconciler.ts
+++ b/apps/freya-backend/src/agent/reconciler.ts
@@ -0,0 +1,70 @@
+import type { ConversationStorage } from "../conversations/storage"
+import type { AgentWorkScheduler } from "./scheduler"
+
+interface AgentResponseReconcilerConfig {
+	storage: ConversationStorage
+	interval: number
+	scheduler: AgentWorkScheduler
+	signal: AbortSignal
+}
+
+export class AgentResponseReconciler {
+	private storage: ConversationStorage
+	private interval: number
+	private scheduler: AgentWorkScheduler
+	private signal: AbortSignal
+
+	private stopLoop: ReturnType<typeof setInterval> | null = null
+
+	constructor({ storage, interval, scheduler, signal }: AgentResponseReconcilerConfig) {
+		this.storage = storage
+		this.interval = interval
+		this.scheduler = scheduler
+		this.signal = signal
+	}
+
+	start() {
+		this.signal.throwIfAborted()
+
+		this.signal.addEventListener(
+			"abort",
+			() => {
+				if (this.stopLoop !== null) {
+					clearInterval(this.stopLoop)
+					this.stopLoop = null
+				}
+			},
+			{ once: true },
+		)
+
+		this.stopLoop = setInterval(this.reconcile.bind(this), this.interval)
+	}
+
+	private async reconcile() {
+		// enqueue pending responses
+		const pendingStates = await this.storage.listPendingResponseStates()
+		const now = new Date().getTime()
+		for (const state of pendingStates) {
+			if (state.maxWaitUntil.getTime() < now) {
+				this.scheduler.enqueueAgentResponse(state.conversationId)
+			}
+		}
+
+		// re-enqueue stuck responses
+		const runningStates = await this.storage.listRunningResponseStates()
+		const stuckIds: string[] = []
+		for (const state of runningStates) {
+			if (state.runningSince && Math.max(now - state.runningSince.getTime(), 0) > 5 * 1000 * 60) {
+				// if the response is running for more than 5 minutes
+				// we assume that its stuck and enqueue it for retry
+				stuckIds.push(state.conversationId)
+			}
+		}
+		if (stuckIds.length > 0) {
+			await this.storage.markResponseStateStatus(stuckIds, "pending")
+			for (const id of stuckIds) {
+				this.scheduler.enqueueAgentResponse(id)
+			}
+		}
+	}
+}
--- a/apps/freya-backend/src/agent/scheduler.ts
+++ b/apps/freya-backend/src/agent/scheduler.ts
@@ -0,0 +1,160 @@
+import type { UserEvent } from "@freya/agent-protocol"
+
+import { ConversationEntryKind, UserMessagePayload } from "@freya/core"
+
+import type { ConversationStorage } from "../conversations/storage"
+import type { Job, JobRegistry } from "../lib/job"
+import type { AgentResponseJobPayload } from "./job"
+import { ConversationNotFoundError } from "../conversations/errors";
+import { ConversationResponseStateStatus } from "../db/schema";
+
+interface AgentMessageSchedulerConfig {
+	storage: ConversationStorage
+	maxWaitTime: number
+
+	/**
+	 * How long to wait before responding to the user.
+	 */
+	waitTIme: number
+
+	jobRegistry: JobRegistry<AgentResponseJobPayload>
+}
+
+/**
+ * Schedules and manages the flow of messages between the user and the query agent for a specific conversation.
+ */
+export class AgentWorkScheduler {
+	private conversationStorage: ConversationStorage
+	private jobRegistry: JobRegistry<AgentResponseJobPayload>
+
+	private timing: {
+		maxWaitTime: number
+		waitTime: number
+	}
+
+	private timers = new Map<string, ReturnType<typeof setTimeout>>()
+	private runningJobs = new Map<string, Job<AgentResponseJobPayload>>()
+
+	constructor(config: AgentMessageSchedulerConfig) {
+		this.conversationStorage = config.storage
+		this.jobRegistry = config.jobRegistry
+		this.timing = {
+			maxWaitTime: config.maxWaitTime,
+			waitTime: config.waitTIme,
+		}
+
+		this.jobRegistry.addEventListener("settled", this.eraseJob.bind(this))
+		this.jobRegistry.addEventListener("cancelled", this.eraseJob.bind(this))
+	}
+
+	async receiveMessage(conversationId: string, message: string) {
+		await this.conversationStorage.transaction(async (storage) => {
+			const now = new Date()
+
+			const entry = await storage.appendEntry(conversationId, {
+				kind: ConversationEntryKind.UserMessage,
+				payload: {
+					role: "user",
+					parts: [{ type: "text", text: message }],
+				} satisfies UserMessagePayload,
+			})
+
+			await storage.upsertConversationResponseState(conversationId, {
+				maxWaitUntil: new Date(now.getTime() + this.timing.maxWaitTime),
+				pendingSinceEntryId: entry.id,
+				status: "pending",
+			})
+
+			return entry
+		})
+		this.scheduleAgentResponse(conversationId, this.timing.waitTime)
+	}
+
+	async receiveUserEvent(conversationId: string, event: UserEvent) {
+		if (event.type === "typing") {
+			await this.delayAgentResponse(conversationId)
+		}
+	}
+
+	enqueueAgentResponse(conversationId: string): void {
+		const existing = this.timers.get(conversationId)
+		if (existing) {
+			clearTimeout(existing)
+			this.timers.delete(conversationId)
+		}
+
+		this.cancelCurrentJob(conversationId)
+
+		const job = this.jobRegistry.addJob({
+			payload: { conversationId },
+		})
+		this.runningJobs.set(conversationId, job)
+	}
+
+	private async delayAgentResponse(conversationId: string) {
+		this.cancelCurrentJob(conversationId);
+
+		try {
+			const ok = await this.conversationStorage.transaction(async (storage) => {
+				const state = await storage.findConversationResponseState(conversationId);
+				if (state && state.status !== ConversationResponseStateStatus.Failed) {
+					await storage.updateConversationResponseState(conversationId, {
+						status: ConversationResponseStateStatus.Pending,
+						// the agent response was cancelled, so its no longer running
+						// clear runningSince timestamp
+						runningSince: null,
+					})
+					return true
+				}
+				return false
+			})
+			if (ok) {
+				await this.scheduleAgentResponse(conversationId, this.timing.waitTime)
+			}
+		} catch (error) {
+			if (error instanceof ConversationNotFoundError) {
+				// the user is typing but there isn't a scheduled agent response yet
+				// which means the user is typing their first message after the agent has previously responded
+				// swallow the error
+			} else {
+				console.error("[agent response scheduler] error delaying agent response", error)
+			}
+			return
+		}
+	}
+
+	private async scheduleAgentResponse(conversationId: string, delay: number) {
+		const existing = this.timers.get(conversationId)
+		if (existing) {
+			clearTimeout(existing)
+		}
+
+		this.cancelCurrentJob(conversationId)
+
+		this.timers.set(
+			conversationId,
+			setTimeout(() => {
+				this.enqueueAgentResponse(conversationId)
+			}, delay),
+		)
+	}
+
+	/**
+	 * cancels the current job for agent response for the given conversation id
+	 * no-op if there is no active job for the conversation.
+	 */
+	private cancelCurrentJob(conversationId: string): void {
+		const job = this.runningJobs.get(conversationId)
+		if (!job) return
+
+		// If an active response is working on stale context, abort it so the next
+		// job can answer using the latest pending user messages.
+		this.jobRegistry.cancelJob(job)
+	}
+
+	private eraseJob(job: Job<AgentResponseJobPayload>) {
+		if (this.runningJobs.get(job.payload.conversationId) === job) {
+			this.runningJobs.delete(job.payload.conversationId)
+		}
+	}
+}
--- a/apps/freya-backend/src/agent/service.ts
+++ b/apps/freya-backend/src/agent/service.ts
@@ -0,0 +1,66 @@
+import type { UserEvent } from "@freya/agent-protocol"
+
+import type { ConversationStorage } from "../conversations/storage"
+import type { NotificationCentral } from "../notification/notification-central"
+import type { UserSessionManager } from "../session"
+
+import { JobRegistry } from "../lib/job"
+import { Worker } from "../lib/worker"
+import { AgentResponseJobExecutor, type AgentResponseJobPayload } from "./job"
+import { AgentResponseReconciler } from "./reconciler"
+import { AgentWorkScheduler } from "./scheduler"
+
+interface AgentServiceConfig {
+	storage: ConversationStorage
+	userSessionManager: UserSessionManager
+	notificationCentral: NotificationCentral
+	signal: AbortSignal
+}
+
+export class AgentService {
+	private readonly storage: ConversationStorage
+	private readonly scheduler: AgentWorkScheduler
+	private readonly reconciler: AgentResponseReconciler
+	private readonly worker: Worker<AgentResponseJobPayload>
+
+	private readonly jobRegistry = new JobRegistry<AgentResponseJobPayload>()
+
+	constructor({ storage, userSessionManager, notificationCentral, signal }: AgentServiceConfig) {
+		this.storage = storage
+		this.scheduler = new AgentWorkScheduler({
+			storage,
+			jobRegistry: this.jobRegistry,
+			waitTIme: 5 * 1000,
+			maxWaitTime: 5 * 1000 * 60,
+		})
+		this.reconciler = new AgentResponseReconciler({
+			signal,
+			storage: this.storage,
+			interval: 60 * 1000,
+			scheduler: this.scheduler,
+		})
+		this.worker = new Worker<AgentResponseJobPayload>({
+			signal,
+			concurrency: 10,
+			registry: this.jobRegistry,
+			runner: new AgentResponseJobExecutor({
+				conversationStorage: storage,
+				notificationCentral,
+				userSessionManager,
+			}),
+		})
+	}
+
+	start() {
+		this.worker.start()
+		this.reconciler.start()
+	}
+
+	async scheduleAgentResponse(conversationId: string, message: string) {
+		await this.scheduler.receiveMessage(conversationId, message)
+	}
+
+	async handleUserEvent(conversationId: string, event: UserEvent) {
+		await this.scheduler.receiveUserEvent(conversationId, event)
+	}
+}
--- a/apps/freya-backend/src/agent/streaming.test.ts
+++ b/apps/freya-backend/src/agent/streaming.test.ts
@@ -9,7 +9,6 @@ import type {
 	QueryAgentEventListener,
 	QueryAgentStreamEvent,
 } from "./query-agent.ts"
-import type { AgentResponseStreamItem } from "./streaming.ts"

 import { streamAgentResponse } from "./streaming.ts"

@@ -47,17 +46,13 @@ describe("streamAgentResponse", () => {
 			{ type: "done" },
 		])

-		const { events, result } = await collectStreamAgentResponse(
+		const events = await collectStreamAgentResponse(
 			streamAgentResponse({
 				agent,
 				input: { message: "hello" },
 			}),
 		)

-		expect(result).toEqual({
-			conversationId: "conversation-1",
-			message: "First message\nSecond message\nThird message",
-		})
 		expect(events).toEqual([
 			{ type: "conversation_started", conversationId: "conversation-1" },
 			{ type: "message_created", text: "First message" },
@@ -74,17 +69,13 @@ describe("streamAgentResponse", () => {
 			{ type: "done" },
 		])

-		const { events, result } = await collectStreamAgentResponse(
+		const events = await collectStreamAgentResponse(
 			streamAgentResponse({
 				agent,
 				input: { message: "hello" },
 			}),
 		)

-		expect(result).toEqual({
-			conversationId: "conversation-1",
-			message: "  const value = 1  \n\n  return value",
-		})
 		expect(events).toEqual([
 			{ type: "conversation_started", conversationId: "conversation-1" },
 			{ type: "message_created", text: "  const value = 1  " },
@@ -122,28 +113,12 @@ describe("streamAgentResponse", () => {
 })

 async function collectStreamAgentResponse(
-	stream: AsyncIterable<AgentResponseStreamItem>,
+	stream: AsyncIterable<AgentEvent>,
 	events: AgentEvent[] = [],
-): Promise<{
-	events: AgentEvent[]
-	result: { message: string; conversationId: string }
-}> {
-	let result: { message: string; conversationId: string } | null = null
-
-	for await (const item of stream) {
-		switch (item.type) {
-			case "event":
-				events.push(item.event)
-				break
-			case "result":
-				result = item.result
-				break
-		}
+): Promise<AgentEvent[]> {
+	for await (const event of stream) {
+		events.push(event)
 	}

-	if (!result) {
-		throw new Error("Expected stream result")
-	}
-
-	return { events, result }
+	return events
 }
--- a/apps/freya-backend/src/agent/streaming.ts
+++ b/apps/freya-backend/src/agent/streaming.ts
@@ -1,10 +1,8 @@
-import type { AgentEvent, SendMessageResult } from "@freya/agent-protocol"
+import type { AgentEvent } from "@freya/agent-protocol"

 import type { QueryAgent, QueryAgentAsk } from "./query-agent.ts"

-export type AgentResponseStreamItem =
-	| { type: "event"; event: AgentEvent }
-	| { type: "result"; result: SendMessageResult }
+export type AgentResponseStreamItem = { type: "event"; event: AgentEvent }

 export async function* streamAgentResponse({
 	agent,
@@ -12,18 +10,18 @@ export async function* streamAgentResponse({
 }: {
 	agent: QueryAgent
 	input: QueryAgentAsk
-}): AsyncGenerator<AgentResponseStreamItem, void, void> {
+}): AsyncGenerator<AgentEvent, void, void> {
 	let message = ""
 	let conversationId: string | null = null
 	const splitter = new AgentMessageSplitter()

-	function messageEvent(text: string): AgentResponseStreamItem | null {
+	function messageEvent(text: string): AgentEvent | null {
 		if (text.trim() === "") return null

-		return { type: "event", event: { type: "message_created", text } }
+		return { type: "message_created", text }
 	}

-	function flushPendingMessage(): AgentResponseStreamItem | null {
+	function flushPendingMessage(): AgentEvent | null {
 		const text = splitter.flush()
 		if (text === null) return null

@@ -31,10 +29,14 @@ export async function* streamAgentResponse({
 	}

 	for await (const event of agent.ask(input)) {
+		if (input.signal?.aborted) {
+			break
+		}
+
 		switch (event.type) {
 			case "conversation":
 				conversationId = event.conversationId
-				yield { type: "event", event: { type: "conversation_started", conversationId } }
+				yield { type: "conversation_started", conversationId }
 				break

 			case "text_delta":
@@ -50,7 +52,7 @@ export async function* streamAgentResponse({
 					const item = flushPendingMessage()
 					if (item) yield item
 				}
-				yield { type: "event", event: { type: "tool_started", toolName: event.toolName } }
+				yield { type: "tool_started", toolName: event.toolName }
 				break

 			case "tool_end":
@@ -59,12 +61,9 @@ export async function* streamAgentResponse({
 					if (item) yield item
 				}
 				yield {
-					type: "event",
-					event: {
-						type: "tool_finished",
-						toolName: event.toolName,
-						ok: event.ok,
-					},
+					type: "tool_finished",
+					toolName: event.toolName,
+					ok: event.ok,
 				}
 				break

@@ -73,7 +72,7 @@ export async function* streamAgentResponse({
 					const item = flushPendingMessage()
 					if (item) yield item
 				}
-				yield { type: "event", event: { type: "message_failed", error: event.message } }
+				yield { type: "message_failed", error: event.message }
 				throw new Error(event.message)

 			case "done":
@@ -81,26 +80,15 @@ export async function* streamAgentResponse({
 					const item = flushPendingMessage()
 					if (item) yield item
 				}
-				const result = createResult(message, conversationId)
-				yield { type: "event", event: { type: "message_finished" } }
-				yield { type: "result", result }
+				yield { type: "message_finished" }
 				return
 		}
 	}

 	const item = flushPendingMessage()
 	if (item) yield item
-	const result = createResult(message, conversationId)
-	yield { type: "event", event: { type: "message_finished" } }
-	yield { type: "result", result }
-}

-function createResult(message: string, conversationId: string | null): SendMessageResult {
-	if (!conversationId) {
-		throw new Error("Agent response stream ended without a conversation id")
-	}
-
-	return { message, conversationId }
+	yield { type: "message_finished" }
 }

 class AgentMessageSplitter {
--- a/apps/freya-backend/src/agent/ws.test.ts
+++ b/apps/freya-backend/src/agent/ws.test.ts
@@ -1,8 +1,10 @@
 import { describe, expect, test } from "bun:test"
 import { Hono } from "hono"

-import type { UserSessionManager } from "../session/index.ts"
+import type { ConversationStorage } from "../conversations/storage.ts"
+import type { NotificationCentral } from "../notification/notification-central.ts"

+import type { AgentService } from "./service.ts"
 import { registerAgentWebSocketHandlers } from "./ws.ts"

 describe("agent websocket handler", () => {
@@ -11,7 +13,9 @@ describe("agent websocket handler", () => {
 		const app = new Hono()

 		registerAgentWebSocketHandlers(app, {
-			sessionManager: {} as UserSessionManager,
+			agentService: {} as AgentService,
+			storage: {} as ConversationStorage,
+			notificationCentral: {} as NotificationCentral,
 			corsMiddleware: async (c, next) => {
 				const origin = c.req.header("origin")
 				if (origin && origin !== "https://app.freya.test") {
@@ -44,7 +48,9 @@ describe("agent websocket handler", () => {
 		const app = new Hono()

 		registerAgentWebSocketHandlers(app, {
-			sessionManager: {} as UserSessionManager,
+			agentService: {} as AgentService,
+			storage: {} as ConversationStorage,
+			notificationCentral: {} as NotificationCentral,
 			corsMiddleware: async (_c, next) => {
 				await next()
 			},
--- a/apps/freya-backend/src/agent/ws.ts
+++ b/apps/freya-backend/src/agent/ws.ts
@@ -1,53 +1,58 @@
-import type { AgentClientApi, AgentServerApi, SendMessageResult } from "@freya/agent-protocol"
+import type { AgentClientApi, AgentServerApi, UserEvent } from "@freya/agent-protocol"
 import type { JrpcChannel, JrpcMessage, JsonRpcMessage } from "@nym.sh/jrpc"
 import type { Hono, MiddlewareHandler } from "hono"
 import type { WSContext } from "hono/ws"

-import { JsonRpcClient, JsonRpcServer } from "@nym.sh/jrpc"
-import { type } from "arktype"
+import { JsonRpcClient, JsonRpcServer, deserializeJrpcMessage } from "@nym.sh/jrpc"
 import { upgradeWebSocket, websocket } from "hono/bun"

 import type { AuthSessionMiddleware } from "../auth/session-middleware.ts"
-import type { UserSessionManager } from "../session/index.ts"
-
-import { streamAgentResponse } from "./streaming.ts"
+import type { ConversationStorage } from "../conversations/storage.ts"
+import type {
+	NotificationCentral,
+	NotificationPayload,
+} from "../notification/notification-central.ts"
+import type { AgentService } from "./service.ts"

 interface AgentWebSocketHandlerDeps {
-	sessionManager: UserSessionManager
+	agentService: AgentService
+	storage: ConversationStorage
+	notificationCentral: NotificationCentral
 	authSessionMiddleware: AuthSessionMiddleware
 	corsMiddleware: MiddlewareHandler
 }

-interface ValidSendMessageInput {
-	message: string
-}
-
 export const agentWebSocket = websocket

-const SendMessageInputBody = type({
-	"+": "reject",
-	message: "string",
-})
-
 export function registerAgentWebSocketHandlers(
 	app: Hono,
-	{ sessionManager, authSessionMiddleware, corsMiddleware }: AgentWebSocketHandlerDeps,
+	{
+		agentService,
+		storage,
+		notificationCentral,
+		authSessionMiddleware,
+		corsMiddleware,
+	}: AgentWebSocketHandlerDeps,
 ): void {
 	app.get(
 		"/api/agent/ws",
 		corsMiddleware,
 		authSessionMiddleware,
-		upgradeWebSocket((c) => {
+		upgradeWebSocket(async (c) => {
 			const user = c.get("user")
 			if (!user) {
 				throw new Error("Authenticated WebSocket user missing")
 			}

+			const conversation = await storage.getOrCreateConversation(user.id)
+
 			const channel = new HonoWebSocketJrpcChannel()
 			const connection = new AgentRpcConnection({
 				channel,
-				sessionManager,
+				notificationCentral,
+				agentService,
 				userId: user.id,
+				conversationId: conversation.id,
 			})

 			return {
@@ -64,6 +69,7 @@ export function registerAgentWebSocketHandlers(
 				},

 				onClose() {
+					connection.close()
 					channel.close()
 				},
 			}
@@ -74,54 +80,52 @@ export function registerAgentWebSocketHandlers(
 class AgentRpcConnection implements AgentServerApi {
 	private readonly client: JsonRpcClient<AgentClientApi>
 	private readonly server: JsonRpcServer<AgentServerApi>
-	private activeMessage: Promise<SendMessageResult> | null = null
-	private readonly sessionManager: UserSessionManager
+	private readonly agentService: AgentService
+	private readonly notificationCentral: NotificationCentral
 	private readonly userId: string
+	private readonly conversationId: string
+
+	private cleanup: (() => void) | null = null

 	constructor({
+		agentService,
+		notificationCentral,
 		channel,
-		sessionManager,
 		userId,
+		conversationId,
 	}: {
+		agentService: AgentService
+		notificationCentral: NotificationCentral
 		channel: JrpcChannel
-		sessionManager: UserSessionManager
 		userId: string
+		conversationId: string
 	}) {
-		this.sessionManager = sessionManager
-		this.userId = userId
 		this.client = new JsonRpcClient<AgentClientApi>(channel)
+		this.agentService = agentService
+		this.notificationCentral = notificationCentral
+		this.userId = userId
+		this.conversationId = conversationId
 		this.server = new JsonRpcServer<AgentServerApi>(
 			{
 				sendMessage: this.sendMessage.bind(this),
+				notify: this.notify.bind(this),
 				ping: this.ping.bind(this),
 			},
 			channel,
 		)
 	}

-	start(): Promise<void> {
-		return this.server.start()
+	notify(event: UserEvent): void {
+		this.agentService.handleUserEvent(this.conversationId, event)
 	}

-	async sendMessage(message: string): Promise<SendMessageResult> {
-		const parsed = SendMessageInputBody({ message })
-		if (parsed instanceof type.errors) {
-			throw new Error(parsed.summary)
-		}
-
-		if (this.activeMessage) {
-			throw new Error("A message is already running")
-		}
-
-		const run = this.runMessage(parsed)
-		this.activeMessage = run
-
+	async sendMessage(message: string): Promise<boolean> {
 		try {
-			return await run
-		} finally {
-			if (this.activeMessage === run) {
-				this.activeMessage = null
-			}
+			await this.agentService.scheduleAgentResponse(this.conversationId, message)
+			return true
+		} catch (error) {
+			console.log("[agent rpc connection] error when scheduling agent response", error)
+			return false
 		}
 	}

@@ -129,26 +133,22 @@ class AgentRpcConnection implements AgentServerApi {
 		return "pong"
 	}

-	private async runMessage(input: ValidSendMessageInput): Promise<SendMessageResult> {
-		const session = await this.sessionManager.getOrCreate(this.userId)
-		let result: SendMessageResult | null = null
+	async start() {
+		this.cleanup = this.notificationCentral.registerListenerForUser(
+			this.userId,
+			this.onNotificationReceived.bind(this),
+		)
+		await this.server.start()
+	}

-		for await (const item of streamAgentResponse({ agent: session.agent, input })) {
-			switch (item.type) {
-				case "event":
-					await this.client.call("notify", item.event)
-					break
-				case "result":
-					result = item.result
-					break
-			}
+	close() {
+		this.cleanup?.()
+	}
+
+	private async onNotificationReceived(notification: NotificationPayload) {
+		if (notification.kind === "agent") {
+			await this.client.call("notify", notification.payload)
 		}
-
-		if (!result) {
-			throw new Error("Agent response stream ended without a result")
-		}
-
-		return result
 	}
 }

@@ -171,7 +171,11 @@ class HonoWebSocketJrpcChannel implements JrpcChannel {
 	}

 	receive(message: unknown): void {
-		const parsed = parseJrpcMessage(message)
+		if (typeof message !== "string") {
+			return
+		}
+
+		const parsed = deserializeJrpcMessage(message)
 		if (!parsed) {
 			this.ws?.close(1003, "Invalid JSON-RPC message")
 			return
@@ -236,52 +240,6 @@ class HonoWebSocketJrpcChannel implements JrpcChannel {
 	}
 }

-function parseJrpcMessage(message: unknown): JrpcMessage | null {
-	const text = webSocketMessageText(message)
-	if (text === null) return null
-
-	try {
-		const value: unknown = JSON.parse(text)
-		return isJrpcMessage(value) ? value : null
-	} catch {
-		return null
-	}
-}
-
-function webSocketMessageText(message: unknown): string | null {
-	if (typeof message === "string") return message
-	if (message instanceof ArrayBuffer) return Buffer.from(message).toString("utf8")
-	if (ArrayBuffer.isView(message)) {
-		return Buffer.from(message.buffer, message.byteOffset, message.byteLength).toString("utf8")
-	}
-
-	return null
-}
-
-function isJrpcMessage(value: unknown): value is JrpcMessage {
-	if (typeof value !== "object" || value === null) return false
-	if (!("jsonrpc" in value) || value.jsonrpc !== "2.0") return false
-
-	if ("method" in value) {
-		return "id" in value && typeof value.id === "number" && typeof value.method === "string"
-	}
-
-	if ("result" in value) {
-		return "id" in value && typeof value.id === "number"
-	}
-
-	if ("error" in value) {
-		return (
-			"id" in value &&
-			typeof value.id === "number" &&
-			typeof value.error === "object" &&
-			value.error !== null
-		)
-	}
-
-	return false
-}
-
 function errorMessage(error: unknown): string {
 	return error instanceof Error ? error.message : String(error)
 }
--- a/apps/freya-backend/src/conversations/db-storage.ts
+++ b/apps/freya-backend/src/conversations/db-storage.ts
@@ -0,0 +1,686 @@
+import {
+	AssistantMessagePayload,
+	AttachmentPayload,
+	ConversationEntryKind,
+	ConversationEntryMetadata,
+	ConversationEntryVisibility,
+	ContextSummaryPayload,
+	GenericObjectPayload,
+	UserMessagePayload,
+	type ConversationEntryPayload,
+} from "@freya/core"
+import { type } from "arktype"
+import { and, asc, desc, eq, gte, inArray } from "drizzle-orm"
+import { alias } from "drizzle-orm/pg-core"
+
+import type { Database } from "../db/index.ts"
+import type {
+	AppendAttachmentEntryInput,
+	AppendAttachmentEntryResult,
+	AppendConversationEntryInput,
+	ConversationEntryRow,
+	ConversationResponseStateRow,
+	ConversationRow,
+	ConversationStorage,
+	CreateFileInput,
+	FileRow,
+	ListConversationEntriesParams,
+	UpdateConversationResponseStateInput,
+	UpsertConversationResponseStateInput,
+} from "./storage.ts"
+
+import {
+	conversationEntries,
+	ConversationResponseStateStatus,
+	conversationResponseState as conversationResponseStateTable,
+	conversations as conversationsTable,
+	files,
+	user,
+} from "../db/schema.ts"
+import { ConversationNotFoundError } from "./errors.ts"
+
+const conversationEntryKind = type.enumerated(...Object.values(ConversationEntryKind))
+const conversationEntryVisibility = type.enumerated(...Object.values(ConversationEntryVisibility))
+const pendingSinceEntry = alias(conversationEntries, "pending_since_entry")
+
+export class DrizzleConversationStorage implements ConversationStorage {
+	private readonly db: Database
+	private readonly inTransaction: boolean
+
+	constructor(db: Database, inTransaction = false) {
+		this.db = db
+		this.inTransaction = inTransaction
+	}
+
+	async transaction<T>(tx: (storage: ConversationStorage) => T | Promise<T>): Promise<T> {
+		if (this.inTransaction) return tx(this)
+
+		return this.db.transaction(async (transactionDb) =>
+			tx(new DrizzleConversationStorage(transactionDb, true)),
+		)
+	}
+
+	async createConversation(userId: string): Promise<ConversationRow> {
+		return insertConversation(this.db, userId)
+	}
+
+	async listUserConversations(userId: string): Promise<ConversationRow[]> {
+		return this.db
+			.select()
+			.from(conversationsTable)
+			.where(eq(conversationsTable.userId, userId))
+			.orderBy(desc(conversationsTable.updatedAt), desc(conversationsTable.createdAt))
+	}
+
+	async findConversation(conversationId: string): Promise<ConversationRow | null> {
+		return findConversation(this.db, conversationId)
+	}
+
+	async getOrCreateConversation(userId: string): Promise<ConversationRow> {
+		return this.write(async (db) => {
+			await requireUserForUpdate(db, userId)
+			const existing = await latestConversation(db, userId)
+			if (existing) return existing
+
+			return insertConversation(db, userId)
+		})
+	}
+
+	async createFile(userId: string, input: CreateFileInput): Promise<FileRow> {
+		return insertFile(this.db, userId, input)
+	}
+
+	async appendEntry(
+		conversationId: string,
+		input: AppendConversationEntryInput,
+	): Promise<ConversationEntryRow> {
+		return this.write((db) => appendEntryToConversation(db, null, conversationId, input))
+	}
+
+	async appendAttachmentEntry(
+		conversationId: string,
+		input: AppendAttachmentEntryInput,
+	): Promise<AppendAttachmentEntryResult> {
+		return this.write((db) => appendAttachmentEntryToConversation(db, null, conversationId, input))
+	}
+
+	async nextSequence(conversationId: string): Promise<number> {
+		return nextSequence(this.db, conversationId)
+	}
+
+	async listUserConversationEntries(
+		userId: string,
+		conversationId: string,
+		params: ListConversationEntriesParams = {},
+	): Promise<ConversationEntryRow[]> {
+		if (!(await findUserConversation(this.db, userId, conversationId))) {
+			throw new ConversationNotFoundError(conversationId, userId)
+		}
+
+		if (params.visibility) {
+			return this.db
+				.select()
+				.from(conversationEntries)
+				.where(
+					and(
+						eq(conversationEntries.conversationId, conversationId),
+						eq(conversationEntries.visibility, params.visibility),
+					),
+				)
+				.orderBy(asc(conversationEntries.sequence))
+		}
+
+		return this.db
+			.select()
+			.from(conversationEntries)
+			.where(eq(conversationEntries.conversationId, conversationId))
+			.orderBy(asc(conversationEntries.sequence))
+	}
+
+	async listPendingUserConversationEntries(
+		userId: string,
+		conversationId: string,
+	): Promise<ConversationEntryRow[]> {
+		const entries = await this.db
+			.select({ entry: conversationEntries })
+			.from(conversationResponseStateTable)
+			.innerJoin(
+				conversationsTable,
+				and(
+					eq(conversationsTable.id, conversationResponseStateTable.conversationId),
+					eq(conversationsTable.userId, userId),
+				),
+			)
+			.innerJoin(
+				pendingSinceEntry,
+				and(
+					eq(pendingSinceEntry.id, conversationResponseStateTable.pendingSinceEntryId),
+					eq(pendingSinceEntry.conversationId, conversationResponseStateTable.conversationId),
+				),
+			)
+			.innerJoin(
+				conversationEntries,
+				and(
+					eq(conversationEntries.conversationId, conversationResponseStateTable.conversationId),
+					eq(conversationEntries.kind, ConversationEntryKind.UserMessage),
+					gte(conversationEntries.sequence, pendingSinceEntry.sequence),
+				),
+			)
+			.where(
+				and(
+					eq(conversationResponseStateTable.conversationId, conversationId),
+					eq(conversationEntries.conversationId, conversationId),
+				),
+			)
+			.orderBy(asc(conversationEntries.sequence))
+
+		if (entries.length > 0) return entries.map(({ entry }) => entry)
+		if (await findUserConversation(this.db, userId, conversationId)) return []
+
+		throw new ConversationNotFoundError(conversationId, userId)
+	}
+
+	async findConversationResponseState(
+		conversationId: string,
+	): Promise<ConversationResponseStateRow | null> {
+		const rows = await this.db
+			.select()
+			.from(conversationResponseStateTable)
+			.where(eq(conversationResponseStateTable.conversationId, conversationId))
+			.limit(1)
+
+		return rows[0] ?? null
+	}
+
+	async listPendingResponseStates(): Promise<ConversationResponseStateRow[]> {
+		const rows = await this.db
+			.select()
+			.from(conversationResponseStateTable)
+			.where(eq(conversationResponseStateTable.status, ConversationResponseStateStatus.Pending))
+
+		return rows
+	}
+
+	async listRunningResponseStates(): Promise<ConversationResponseStateRow[]> {
+		const rows = await this.db
+			.select()
+			.from(conversationResponseStateTable)
+			.where(eq(conversationResponseStateTable.status, ConversationResponseStateStatus.Running))
+
+		return rows
+	}
+
+	async upsertConversationResponseState(
+		conversationId: string,
+		input: UpsertConversationResponseStateInput,
+	): Promise<ConversationResponseStateRow> {
+		const now = new Date()
+
+		return this.write(async (db) => {
+			if (!(await findConversationByIdForUpdate(db, conversationId))) {
+				throw new ConversationNotFoundError(conversationId, "")
+			}
+
+			const rows = await db
+				.insert(conversationResponseStateTable)
+				.values({
+					conversationId,
+					status: input.status ?? ConversationResponseStateStatus.Pending,
+					pendingSinceEntryId: input.pendingSinceEntryId,
+					maxWaitUntil: input.maxWaitUntil,
+					runningSince: input.runningSince ?? null,
+					updatedAt: now,
+				})
+				.onConflictDoUpdate({
+					target: conversationResponseStateTable.conversationId,
+					set: {
+						status: input.status ?? ConversationResponseStateStatus.Pending,
+						maxWaitUntil: input.maxWaitUntil,
+						runningSince: input.runningSince ?? null,
+						updatedAt: now,
+					},
+				})
+				.returning()
+
+			return requireRow(rows)
+		})
+	}
+
+	async updateConversationResponseState(
+		conversationId: string,
+		input: UpdateConversationResponseStateInput,
+	): Promise<ConversationResponseStateRow | null> {
+		return this.write(async (db) => {
+			if (!(await findConversationByIdForUpdate(db, conversationId))) {
+				throw new ConversationNotFoundError(conversationId, "")
+			}
+
+			const rows = await db
+				.update(conversationResponseStateTable)
+				.set({
+					status: input.status,
+					pendingSinceEntryId: input.pendingSinceEntryId,
+					maxWaitUntil: input.maxWaitUntil,
+					runningSince: input.runningSince,
+					updatedAt: new Date(),
+				})
+				.where(eq(conversationResponseStateTable.conversationId, conversationId))
+				.returning()
+
+			return rows[0] ?? null
+		})
+	}
+
+	async markResponseStateStatus(
+		conversationIds: string[],
+		status: ConversationResponseStateStatus,
+	): Promise<ConversationResponseStateRow[]> {
+		return this.write(async (db) => {
+			const now = new Date()
+
+			let runningSince: Date | null
+			switch (status) {
+				case "pending":
+				case "failed":
+					runningSince = null
+					break
+				case "running":
+					runningSince = now
+					break
+			}
+
+			const rows = await db
+				.update(conversationResponseStateTable)
+				.set({
+					status,
+					runningSince,
+					updatedAt: now,
+				})
+				.where(inArray(conversationResponseStateTable.conversationId, conversationIds))
+				.returning()
+
+			return rows
+		})
+	}
+
+	async claimPendingConversationResponseState(
+		conversationId: string,
+	): Promise<ConversationResponseStateRow | null> {
+		return this.write(async (db) => {
+			const now = new Date()
+			const rows = await db
+				.update(conversationResponseStateTable)
+				.set({
+					status: "running",
+					runningSince: now,
+					updatedAt: now,
+				})
+				.where(
+					and(
+						eq(conversationResponseStateTable.conversationId, conversationId),
+						eq(conversationResponseStateTable.status, "pending"),
+					),
+				)
+				.returning()
+
+			return rows[0] ?? null
+		})
+	}
+
+	async clearConversationResponseState(conversationId: string): Promise<void> {
+		await this.write(async (db) => {
+			if (!(await findConversationByIdForUpdate(db, conversationId))) {
+				throw new ConversationNotFoundError(conversationId, "")
+			}
+
+			await db
+				.delete(conversationResponseStateTable)
+				.where(eq(conversationResponseStateTable.conversationId, conversationId))
+		})
+	}
+
+	private async write<T>(fn: (db: Database) => Promise<T>): Promise<T> {
+		if (this.inTransaction) return fn(this.db)
+
+		return this.db.transaction(fn)
+	}
+}
+
+export function createConversationStorage(db: Database): ConversationStorage {
+	return new DrizzleConversationStorage(db)
+}
+
+export function conversations(db: Database, userId: string) {
+	const storage = createConversationStorage(db)
+
+	return {
+		createConversation(): Promise<ConversationRow> {
+			return storage.createConversation(userId)
+		},
+
+		listConversations(): Promise<ConversationRow[]> {
+			return storage.listUserConversations(userId)
+		},
+
+		getConversation(conversationId: string): Promise<ConversationRow | null> {
+			return findUserConversation(db, userId, conversationId)
+		},
+
+		getOrCreateConversation(): Promise<ConversationRow> {
+			return storage.getOrCreateConversation(userId)
+		},
+
+		createFile(input: CreateFileInput): Promise<FileRow> {
+			return storage.createFile(userId, input)
+		},
+
+		appendEntry(
+			conversationId: string,
+			input: AppendConversationEntryInput,
+		): Promise<ConversationEntryRow> {
+			return db.transaction((tx) => appendEntryToConversation(tx, userId, conversationId, input))
+		},
+
+		appendAttachmentEntry(
+			conversationId: string,
+			input: AppendAttachmentEntryInput,
+		): Promise<AppendAttachmentEntryResult> {
+			return db.transaction((tx) =>
+				appendAttachmentEntryToConversation(tx, userId, conversationId, input),
+			)
+		},
+
+		listEntries(
+			conversationId: string,
+			params: ListConversationEntriesParams = {},
+		): Promise<ConversationEntryRow[]> {
+			return storage.listUserConversationEntries(userId, conversationId, params)
+		},
+	}
+}
+
+export function conversationResponse(db: Database, _userId: string, conversationId: string) {
+	const storage = createConversationStorage(db)
+
+	return {
+		get(): Promise<ConversationResponseStateRow | null> {
+			return storage.findConversationResponseState(conversationId)
+		},
+
+		upsert(input: UpsertConversationResponseStateInput): Promise<ConversationResponseStateRow> {
+			return storage.upsertConversationResponseState(conversationId, input)
+		},
+
+		update(
+			input: UpdateConversationResponseStateInput,
+		): Promise<ConversationResponseStateRow | null> {
+			return storage.updateConversationResponseState(conversationId, input)
+		},
+
+		clear(): Promise<void> {
+			return storage.clearConversationResponseState(conversationId)
+		},
+	}
+}
+
+function payloadForKind(
+	kind: ConversationEntryKind,
+	payload: AppendConversationEntryInput["payload"],
+): ConversationEntryPayload {
+	switch (kind) {
+		case ConversationEntryKind.UserMessage:
+			return UserMessagePayload.assert(payload)
+		case ConversationEntryKind.AssistantMessage:
+			return AssistantMessagePayload.assert(payload)
+		case ConversationEntryKind.Attachment:
+			return AttachmentPayload.assert(payload)
+		case ConversationEntryKind.ContextSummary:
+			return ContextSummaryPayload.assert(payload)
+		case ConversationEntryKind.ToolCall:
+		case ConversationEntryKind.ToolResult:
+		case ConversationEntryKind.SystemNote:
+			return GenericObjectPayload.assert(payload)
+	}
+}
+
+async function appendEntryToConversation(
+	db: Database,
+	userId: string | null,
+	conversationId: string,
+	input: AppendConversationEntryInput,
+): Promise<ConversationEntryRow> {
+	const kind = conversationEntryKind.assert(input.kind)
+	const visibility = conversationEntryVisibility.assert(
+		input.visibility ?? defaultVisibilityForKind(kind),
+	)
+	const payload = payloadForKind(kind, input.payload)
+	const metadata = ConversationEntryMetadata.assert(input.metadata ?? {})
+	let fileId: string | null = null
+
+	if (input.kind === ConversationEntryKind.Attachment) {
+		fileId = input.fileId
+	}
+
+	const conversation = userId
+		? await findConversationForUpdate(db, userId, conversationId)
+		: await findConversationByIdForUpdate(db, conversationId)
+	if (!conversation) {
+		throw new ConversationNotFoundError(conversationId, userId ?? "")
+	}
+	if (fileId) await requireFile(db, conversation.userId, fileId)
+
+	const sequence = await nextSequence(db, conversationId)
+	const rows = await db
+		.insert(conversationEntries)
+		.values({
+			conversationId,
+			sequence,
+			kind,
+			visibility,
+			fileId,
+			payload,
+			metadata,
+		})
+		.returning()
+
+	await touchConversation(db, conversation.userId, conversationId)
+	return requireRow(rows)
+}
+
+async function appendAttachmentEntryToConversation(
+	db: Database,
+	userId: string | null,
+	conversationId: string,
+	input: AppendAttachmentEntryInput,
+): Promise<AppendAttachmentEntryResult> {
+	const payload = AttachmentPayload.assert(input.payload)
+	const visibility = conversationEntryVisibility.assert(
+		input.visibility ?? defaultVisibilityForKind(ConversationEntryKind.Attachment),
+	)
+	const metadata = ConversationEntryMetadata.assert(input.metadata ?? {})
+	const conversation = userId
+		? await findConversationForUpdate(db, userId, conversationId)
+		: await findConversationByIdForUpdate(db, conversationId)
+
+	if (!conversation) {
+		throw new ConversationNotFoundError(conversationId, userId ?? "")
+	}
+
+	const file = await insertFile(db, conversation.userId, input.file)
+	const sequence = await nextSequence(db, conversationId)
+	const rows = await db
+		.insert(conversationEntries)
+		.values({
+			conversationId,
+			sequence,
+			kind: ConversationEntryKind.Attachment,
+			visibility,
+			fileId: file.id,
+			payload,
+			metadata,
+		})
+		.returning()
+
+	await touchConversation(db, conversation.userId, conversationId)
+	return {
+		file,
+		entry: requireRow(rows),
+	}
+}
+
+async function requireUserForUpdate(db: Database, userId: string): Promise<void> {
+	const rows = await db
+		.select({ id: user.id })
+		.from(user)
+		.where(eq(user.id, userId))
+		.limit(1)
+		.for("update")
+
+	requireRow(rows, `User not found: ${userId}`)
+}
+
+export async function findConversation(
+	db: Database,
+	conversationId: string,
+): Promise<ConversationRow | null> {
+	const rows = await db
+		.select()
+		.from(conversationsTable)
+		.where(eq(conversationsTable.id, conversationId))
+		.limit(1)
+
+	return rows[0] ?? null
+}
+
+async function findUserConversation(
+	db: Database,
+	userId: string,
+	conversationId: string,
+): Promise<ConversationRow | null> {
+	const rows = await db
+		.select()
+		.from(conversationsTable)
+		.where(and(eq(conversationsTable.id, conversationId), eq(conversationsTable.userId, userId)))
+		.limit(1)
+
+	return rows[0] ?? null
+}
+
+async function findConversationForUpdate(
+	db: Database,
+	userId: string,
+	conversationId: string,
+): Promise<ConversationRow | null> {
+	const rows = await db
+		.select()
+		.from(conversationsTable)
+		.where(and(eq(conversationsTable.id, conversationId), eq(conversationsTable.userId, userId)))
+		.limit(1)
+		.for("update")
+
+	return rows[0] ?? null
+}
+
+async function findConversationByIdForUpdate(
+	db: Database,
+	conversationId: string,
+): Promise<ConversationRow | null> {
+	const rows = await db
+		.select()
+		.from(conversationsTable)
+		.where(eq(conversationsTable.id, conversationId))
+		.limit(1)
+		.for("update")
+
+	return rows[0] ?? null
+}
+
+async function latestConversation(db: Database, userId: string): Promise<ConversationRow | null> {
+	const rows = await db
+		.select()
+		.from(conversationsTable)
+		.where(eq(conversationsTable.userId, userId))
+		.orderBy(desc(conversationsTable.updatedAt), desc(conversationsTable.createdAt))
+		.limit(1)
+
+	return rows[0] ?? null
+}
+
+async function insertConversation(db: Database, userId: string): Promise<ConversationRow> {
+	const rows = await db
+		.insert(conversationsTable)
+		.values({
+			userId,
+		})
+		.returning()
+
+	return requireRow(rows)
+}
+
+async function requireFile(db: Database, userId: string, fileId: string): Promise<FileRow> {
+	const rows = await db
+		.select()
+		.from(files)
+		.where(and(eq(files.id, fileId), eq(files.userId, userId)))
+		.limit(1)
+
+	return requireRow(rows, `File not found: ${fileId}`)
+}
+
+async function insertFile(db: Database, userId: string, input: CreateFileInput): Promise<FileRow> {
+	const rows = await db
+		.insert(files)
+		.values({
+			userId,
+			storageKey: input.storageKey,
+			originalName: input.originalName ?? null,
+			mimeType: input.mimeType,
+			sizeBytes: input.sizeBytes,
+			metadata: input.metadata ?? {},
+		})
+		.returning()
+
+	return requireRow(rows)
+}
+
+async function touchConversation(
+	db: Database,
+	userId: string,
+	conversationId: string,
+): Promise<void> {
+	await db
+		.update(conversationsTable)
+		.set({ updatedAt: new Date() })
+		.where(and(eq(conversationsTable.id, conversationId), eq(conversationsTable.userId, userId)))
+}
+
+async function nextSequence(db: Database, conversationId: string): Promise<number> {
+	const rows = await db
+		.select({ sequence: conversationEntries.sequence })
+		.from(conversationEntries)
+		.where(eq(conversationEntries.conversationId, conversationId))
+		.orderBy(desc(conversationEntries.sequence))
+		.limit(1)
+
+	return (rows[0]?.sequence ?? 0) + 1
+}
+
+function requireRow<T>(rows: T[], message = "Expected database row"): T {
+	const row = rows[0]
+	if (!row) throw new Error(message)
+	return row
+}
+
+function defaultVisibilityForKind(kind: ConversationEntryKind): ConversationEntryVisibility {
+	switch (kind) {
+		case ConversationEntryKind.UserMessage:
+		case ConversationEntryKind.AssistantMessage:
+		case ConversationEntryKind.Attachment:
+			return ConversationEntryVisibility.UserVisible
+		case ConversationEntryKind.ToolCall:
+		case ConversationEntryKind.ToolResult:
+		case ConversationEntryKind.ContextSummary:
+		case ConversationEntryKind.SystemNote:
+			return ConversationEntryVisibility.Internal
+	}
+}
--- a/apps/freya-backend/src/conversations/http.test.ts
+++ b/apps/freya-backend/src/conversations/http.test.ts
@@ -25,7 +25,7 @@ const listEntriesCalls: Array<{
 	params: ListConversationEntriesParams
 }> = []

-mock.module("./storage.ts", () => ({
+mock.module("./db-storage.ts", () => ({
 	conversations: (_db: Database, userId: string) => ({
 		async listConversations(): Promise<ConversationRow[]> {
 			return conversationRowsByUser.get(userId) ?? []
--- a/apps/freya-backend/src/conversations/http.ts
+++ b/apps/freya-backend/src/conversations/http.ts
@@ -8,8 +8,8 @@ import type { AuthSessionMiddleware } from "../auth/session-middleware.ts"
 import type { Database } from "../db/index.ts"
 import type { ConversationRow } from "./storage.ts"

+import { conversations } from "./db-storage.ts"
 import { ConversationNotFoundError } from "./errors.ts"
-import { conversations } from "./storage.ts"

 /** Hono environment populated by the conversations route middleware. */
 type Env = {
--- a/apps/freya-backend/src/conversations/storage.ts
+++ b/apps/freya-backend/src/conversations/storage.ts
@@ -2,28 +2,70 @@ import {
 	AssistantMessagePayload,
 	AttachmentPayload,
 	ConversationEntryKind,
+	ConversationEntryMetadata,
 	ConversationEntryVisibility,
 	ContextSummaryPayload,
-	ConversationEntryMetadata,
 	GenericObjectPayload,
 	UserMessagePayload,
-	type ConversationEntryPayload,
 } from "@freya/core"
-import { type } from "arktype"
-import { and, asc, desc, eq } from "drizzle-orm"
-
-import type { Database } from "../db/index.ts"

 import {
 	conversationEntries,
+	conversationResponseState as conversationResponseStateTable,
 	conversations as conversationsTable,
 	files,
-	user,
+	type ConversationResponseStateStatus,
 } from "../db/schema.ts"
-import { ConversationNotFoundError } from "./errors.ts"

-const conversationEntryKind = type.enumerated(...Object.values(ConversationEntryKind))
-const conversationEntryVisibility = type.enumerated(...Object.values(ConversationEntryVisibility))
+export interface ConversationStorage {
+	transaction<T>(tx: (storage: ConversationStorage) => T | Promise<T>): Promise<T>
+	createConversation(userId: string): Promise<ConversationRow>
+	listUserConversations(userId: string): Promise<ConversationRow[]>
+	findConversation(conversationId: string): Promise<ConversationRow | null>
+	getOrCreateConversation(userId: string): Promise<ConversationRow>
+	createFile(userId: string, input: CreateFileInput): Promise<FileRow>
+	appendEntry(
+		conversationId: string,
+		input: AppendConversationEntryInput,
+	): Promise<ConversationEntryRow>
+	appendAttachmentEntry(
+		conversationId: string,
+		input: AppendAttachmentEntryInput,
+	): Promise<AppendAttachmentEntryResult>
+	nextSequence(conversationId: string): Promise<number>
+	listUserConversationEntries(
+		userId: string,
+		conversationId: string,
+		params?: ListConversationEntriesParams,
+	): Promise<ConversationEntryRow[]>
+	listPendingUserConversationEntries(
+		userId: string,
+		conversationId: string,
+	): Promise<ConversationEntryRow[]>
+	findConversationResponseState(
+		conversationId: string,
+	): Promise<ConversationResponseStateRow | null>
+	// TODO: add pagination support
+	listPendingResponseStates(): Promise<ConversationResponseStateRow[]>
+	// TODO: add pagination support
+	listRunningResponseStates(): Promise<ConversationResponseStateRow[]>
+	upsertConversationResponseState(
+		conversationId: string,
+		input: UpsertConversationResponseStateInput,
+	): Promise<ConversationResponseStateRow>
+	updateConversationResponseState(
+		conversationId: string,
+		input: UpdateConversationResponseStateInput,
+	): Promise<ConversationResponseStateRow | null>
+	markResponseStateStatus(
+		conversationIds: string[],
+		status: ConversationResponseStateStatus,
+	): Promise<ConversationResponseStateRow[]>
+	claimPendingConversationResponseState(
+		conversationId: string,
+	): Promise<ConversationResponseStateRow | null>
+	clearConversationResponseState(conversationId: string): Promise<void>
+}

 /** Database row shape for a conversation owned by a user. */
 export type ConversationRow = typeof conversationsTable.$inferSelect
@@ -31,6 +73,9 @@ export type ConversationRow = typeof conversationsTable.$inferSelect
 /** Database row shape for an entry in a conversation timeline. */
 export type ConversationEntryRow = typeof conversationEntries.$inferSelect

+/** Database row shape for pending assistant response state in a conversation. */
+export type ConversationResponseStateRow = typeof conversationResponseStateTable.$inferSelect
+
 /** Database row shape for an uploaded file referenced by conversations. */
 export type FileRow = typeof files.$inferSelect

@@ -99,291 +144,26 @@ export interface ListConversationEntriesParams {
 	visibility?: ConversationEntryVisibility
 }

-export function conversations(db: Database, userId: string) {
-	const storage = {
-		async createConversation(): Promise<ConversationRow> {
-			return insertConversation(db, userId)
-		},
-
-		async listConversations(): Promise<ConversationRow[]> {
-			return db
-				.select()
-				.from(conversationsTable)
-				.where(eq(conversationsTable.userId, userId))
-				.orderBy(desc(conversationsTable.updatedAt), desc(conversationsTable.createdAt))
-		},
-
-		async getConversation(conversationId: string): Promise<ConversationRow | null> {
-			const rows = await db
-				.select()
-				.from(conversationsTable)
-				.where(
-					and(eq(conversationsTable.id, conversationId), eq(conversationsTable.userId, userId)),
-				)
-				.limit(1)
-
-			return rows[0] ?? null
-		},
-
-		async getOrCreateConversation(): Promise<ConversationRow> {
-			return db.transaction(async (tx) => {
-				await requireUserForUpdate(tx, userId)
-				const existing = await latestConversation(tx, userId)
-				if (existing) return existing
-
-				return insertConversation(tx, userId)
-			})
-		},
-
-		async createFile(input: CreateFileInput): Promise<FileRow> {
-			return insertFile(db, userId, input)
-		},
-
-		async appendEntry(
-			conversationId: string,
-			input: AppendConversationEntryInput,
-		): Promise<ConversationEntryRow> {
-			const kind = conversationEntryKind.assert(input.kind)
-			const visibility = conversationEntryVisibility.assert(
-				input.visibility ?? defaultVisibilityForKind(kind),
-			)
-			const payload = payloadForKind(kind, input.payload)
-			const metadata = ConversationEntryMetadata.assert(input.metadata ?? {})
-			let fileId: string | null = null
-
-			if (input.kind === ConversationEntryKind.Attachment) {
-				fileId = input.fileId
-				await requireFile(db, userId, fileId)
-			}
-
-			const rows = await db.transaction(async (tx) => {
-				if (!(await findConversationForUpdate(tx, userId, conversationId))) {
-					throw new ConversationNotFoundError(conversationId, userId)
-				}
-				const sequence = await nextSequence(tx, conversationId)
-
-				const rows = await tx
-					.insert(conversationEntries)
-					.values({
-						conversationId,
-						sequence,
-						kind,
-						visibility,
-						fileId,
-						payload,
-						metadata,
-					})
-					.returning()
-
-				await touchConversation(tx, userId, conversationId)
-				return rows
-			})
-
-			return requireRow(rows)
-		},
-
-		async appendAttachmentEntry(
-			conversationId: string,
-			input: AppendAttachmentEntryInput,
-		): Promise<AppendAttachmentEntryResult> {
-			const payload = AttachmentPayload.assert(input.payload)
-			const visibility = conversationEntryVisibility.assert(
-				input.visibility ?? defaultVisibilityForKind(ConversationEntryKind.Attachment),
-			)
-			const metadata = ConversationEntryMetadata.assert(input.metadata ?? {})
-
-			return db.transaction(async (tx) => {
-				if (!(await findConversationForUpdate(tx, userId, conversationId))) {
-					throw new ConversationNotFoundError(conversationId, userId)
-				}
-
-				const file = await insertFile(tx, userId, input.file)
-				const sequence = await nextSequence(tx, conversationId)
-				const rows = await tx
-					.insert(conversationEntries)
-					.values({
-						conversationId,
-						sequence,
-						kind: ConversationEntryKind.Attachment,
-						visibility,
-						fileId: file.id,
-						payload,
-						metadata,
-					})
-					.returning()
-
-				await touchConversation(tx, userId, conversationId)
-				return {
-					file,
-					entry: requireRow(rows),
-				}
-			})
-		},
-
-		async listEntries(
-			conversationId: string,
-			params: ListConversationEntriesParams = {},
-		): Promise<ConversationEntryRow[]> {
-			if (!(await storage.getConversation(conversationId))) {
-				throw new ConversationNotFoundError(conversationId, userId)
-			}
-
-			if (params.visibility) {
-				return db
-					.select()
-					.from(conversationEntries)
-					.where(
-						and(
-							eq(conversationEntries.conversationId, conversationId),
-							eq(conversationEntries.visibility, params.visibility),
-						),
-					)
-					.orderBy(asc(conversationEntries.sequence))
-			}
-
-			return db
-				.select()
-				.from(conversationEntries)
-				.where(eq(conversationEntries.conversationId, conversationId))
-				.orderBy(asc(conversationEntries.sequence))
-		},
-	}
-
-	return storage
+/** Input for creating or replacing pending assistant response state. */
+export interface UpsertConversationResponseStateInput {
+	status?: ConversationResponseStateStatus
+	pendingSinceEntryId: string
+	maxWaitUntil: Date
+	runningSince?: Date | null
 }

-function payloadForKind(
-	kind: ConversationEntryKind,
-	payload: AppendConversationEntryInput["payload"],
-): ConversationEntryPayload {
-	switch (kind) {
-		case ConversationEntryKind.UserMessage:
-			return UserMessagePayload.assert(payload)
-		case ConversationEntryKind.AssistantMessage:
-			return AssistantMessagePayload.assert(payload)
-		case ConversationEntryKind.Attachment:
-			return AttachmentPayload.assert(payload)
-		case ConversationEntryKind.ContextSummary:
-			return ContextSummaryPayload.assert(payload)
-		case ConversationEntryKind.ToolCall:
-		case ConversationEntryKind.ToolResult:
-		case ConversationEntryKind.SystemNote:
-			return GenericObjectPayload.assert(payload)
-	}
+/** Input for patching pending assistant response state. */
+export interface UpdateConversationResponseStateInput {
+	status?: ConversationResponseStateStatus
+	pendingSinceEntryId?: string
+	maxWaitUntil?: Date
+	runningSince?: Date | null
 }

-async function requireUserForUpdate(db: Database, userId: string): Promise<void> {
-	const rows = await db
-		.select({ id: user.id })
-		.from(user)
-		.where(eq(user.id, userId))
-		.limit(1)
-		.for("update")
-
-	requireRow(rows, `User not found: ${userId}`)
-}
-
-async function findConversationForUpdate(
-	db: Database,
-	userId: string,
-	conversationId: string,
-): Promise<ConversationRow | null> {
-	const rows = await db
-		.select()
-		.from(conversationsTable)
-		.where(and(eq(conversationsTable.id, conversationId), eq(conversationsTable.userId, userId)))
-		.limit(1)
-		.for("update")
-
-	return rows[0] ?? null
-}
-
-async function latestConversation(db: Database, userId: string): Promise<ConversationRow | null> {
-	const rows = await db
-		.select()
-		.from(conversationsTable)
-		.where(eq(conversationsTable.userId, userId))
-		.orderBy(desc(conversationsTable.updatedAt), desc(conversationsTable.createdAt))
-		.limit(1)
-
-	return rows[0] ?? null
-}
-
-async function insertConversation(db: Database, userId: string): Promise<ConversationRow> {
-	const rows = await db
-		.insert(conversationsTable)
-		.values({
-			userId,
-		})
-		.returning()
-
-	return requireRow(rows)
-}
-
-async function requireFile(db: Database, userId: string, fileId: string): Promise<FileRow> {
-	const rows = await db
-		.select()
-		.from(files)
-		.where(and(eq(files.id, fileId), eq(files.userId, userId)))
-		.limit(1)
-
-	return requireRow(rows, `File not found: ${fileId}`)
-}
-
-async function insertFile(db: Database, userId: string, input: CreateFileInput): Promise<FileRow> {
-	const rows = await db
-		.insert(files)
-		.values({
-			userId,
-			storageKey: input.storageKey,
-			originalName: input.originalName ?? null,
-			mimeType: input.mimeType,
-			sizeBytes: input.sizeBytes,
-			metadata: input.metadata ?? {},
-		})
-		.returning()
-
-	return requireRow(rows)
-}
-
-async function touchConversation(
-	db: Database,
-	userId: string,
-	conversationId: string,
-): Promise<void> {
-	await db
-		.update(conversationsTable)
-		.set({ updatedAt: new Date() })
-		.where(and(eq(conversationsTable.id, conversationId), eq(conversationsTable.userId, userId)))
-}
-
-async function nextSequence(db: Database, conversationId: string): Promise<number> {
-	const rows = await db
-		.select({ sequence: conversationEntries.sequence })
-		.from(conversationEntries)
-		.where(eq(conversationEntries.conversationId, conversationId))
-		.orderBy(desc(conversationEntries.sequence))
-		.limit(1)
-
-	return (rows[0]?.sequence ?? 0) + 1
-}
-
-function requireRow<T>(rows: T[], message = "Expected database row"): T {
-	const row = rows[0]
-	if (!row) throw new Error(message)
-	return row
-}
-
-function defaultVisibilityForKind(kind: ConversationEntryKind): ConversationEntryVisibility {
-	switch (kind) {
-		case ConversationEntryKind.UserMessage:
-		case ConversationEntryKind.AssistantMessage:
-		case ConversationEntryKind.Attachment:
-			return ConversationEntryVisibility.UserVisible
-		case ConversationEntryKind.ToolCall:
-		case ConversationEntryKind.ToolResult:
-		case ConversationEntryKind.ContextSummary:
-		case ConversationEntryKind.SystemNote:
-			return ConversationEntryVisibility.Internal
-	}
-}
+export {
+	createConversationStorage,
+	conversationResponse,
+	conversations,
+	DrizzleConversationStorage,
+	findConversation,
+} from "./db-storage.ts"
--- a/apps/freya-backend/src/db/schema.ts
+++ b/apps/freya-backend/src/db/schema.ts
@@ -48,6 +48,15 @@ const bytea = customType<{ data: Buffer }>({
 	},
 })

+export const ConversationResponseStateStatus = {
+	Pending: "pending",
+	Running: "running",
+	Failed: "failed",
+} as const
+
+export type ConversationResponseStateStatus =
+	(typeof ConversationResponseStateStatus)[keyof typeof ConversationResponseStateStatus]
+
 export const userSources = pgTable(
 	"user_sources",
 	{
@@ -146,6 +155,38 @@ export const conversationEntries = pgTable(
 	],
 )

+export const conversationResponseState = pgTable(
+	"conversation_response_state",
+	{
+		conversationId: uuid("conversation_id")
+			.primaryKey()
+			.references(() => conversations.id, { onDelete: "cascade" }),
+		status: text("status")
+			.$type<ConversationResponseStateStatus>()
+			.notNull()
+			.default(ConversationResponseStateStatus.Pending),
+		pendingSinceEntryId: uuid("pending_since_entry_id")
+			.notNull()
+			.references(() => conversationEntries.id, { onDelete: "cascade" }),
+		maxWaitUntil: timestamp("max_wait_until").notNull(),
+		runningSince: timestamp("running_since"),
+		createdAt: timestamp("created_at").notNull().defaultNow(),
+		updatedAt: timestamp("updated_at")
+			.notNull()
+			.defaultNow()
+			.$onUpdate(() => new Date()),
+	},
+	(t) => [
+		index("conversation_response_state_status_max_wait_until_idx").on(t.status, t.maxWaitUntil),
+		index("conversation_response_state_running_since_idx").on(t.runningSince),
+		index("conversation_response_state_pending_since_entry_id_idx").on(t.pendingSinceEntryId),
+		check(
+			"conversation_response_state_status_check",
+			sql`${t.status} in ('pending', 'running', 'failed')`,
+		),
+	],
+)
+
 // ---------------------------------------------------------------------------
 // FREYA — reminders source storage
 // ---------------------------------------------------------------------------
--- a/apps/freya-backend/src/engine/http.test.ts
+++ b/apps/freya-backend/src/engine/http.test.ts
@@ -14,7 +14,6 @@ interface FeedResponse {
 	items: Array<{
 		id: string
 		type: string
-		priority: number
 		timestamp: string
 		data: Record<string, unknown>
 	}>
@@ -85,7 +84,7 @@ mock.module("../sources/user-sources.ts", () => ({
 	}),
 }))

-mock.module("../conversations/storage.ts", () => ({
+mock.module("../conversations/db-storage.ts", () => ({
 	conversations: (_db: Database, userId: string) => ({
 		async getOrCreateConversation() {
 			return { id: `conversation-${userId}` }
@@ -118,7 +117,6 @@ describe("GET /api/feed", () => {
 				id: "item-1",
 				sourceId: "test",
 				type: "test",
-				priority: 0.8,
 				timestamp: new Date("2025-01-01T00:00:00.000Z"),
 				data: { value: 42 },
 			},
@@ -149,7 +147,6 @@ describe("GET /api/feed", () => {
 		expect(body.items).toHaveLength(1)
 		expect(body.items[0]!.id).toBe("item-1")
 		expect(body.items[0]!.type).toBe("test")
-		expect(body.items[0]!.priority).toBe(0.8)
 		expect(body.items[0]!.timestamp).toBe("2025-01-01T00:00:00.000Z")
 		expect(body.errors).toHaveLength(0)
 	})
@@ -160,7 +157,6 @@ describe("GET /api/feed", () => {
 				id: "fresh-1",
 				sourceId: "test",
 				type: "test",
-				priority: 0.5,
 				timestamp: new Date("2025-06-01T12:00:00.000Z"),
 				data: { fresh: true },
 			},
--- a/apps/freya-backend/src/enhancement/schema.test.ts
+++ b/apps/freya-backend/src/enhancement/schema.test.ts
@@ -135,8 +135,9 @@ describe("schema sync", () => {

 			// JSON Schema structure matches
 			const jsonSchema = enhancementResultJsonSchema
+			const payloadKeys = Object.keys(payload).sort() as Array<(typeof jsonSchema.required)[number]>
 			expect(Object.keys(jsonSchema.properties).sort()).toEqual(Object.keys(payload).sort())
-			expect([...jsonSchema.required].sort()).toEqual(Object.keys(payload).sort())
+			expect([...jsonSchema.required].sort()).toEqual(payloadKeys)

 			// syntheticItems item schema has the right required fields
 			const itemSchema = jsonSchema.properties.syntheticItems.items
--- a/apps/freya-backend/src/lib/job.ts
+++ b/apps/freya-backend/src/lib/job.ts
@@ -0,0 +1,116 @@
+import { Queue } from "./queue"
+
+const JobStatus = {
+	Pending: "pending",
+	Running: "running",
+} as const
+type JobStatus = (typeof JobStatus)[keyof typeof JobStatus]
+
+export interface Job<Payload> {
+	id: number
+	payload: Payload
+	signal: AbortSignal
+}
+
+interface PendingJob<Payload> {
+	status: typeof JobStatus.Pending
+	controller: AbortController
+	job: Job<Payload>
+}
+
+interface RunningJob<Payload> {
+	status: typeof JobStatus.Running
+	controller: AbortController
+	job: Job<Payload>
+}
+
+type JobState<Payload> = PendingJob<Payload> | RunningJob<Payload>
+
+type JobEventListener<Payload> = (job: Job<Payload>) => void
+
+type JobEvent = "settled" | "cancelled"
+
+export class JobRegistry<Payload> {
+	private queue = new Queue<Job<Payload>>()
+
+	private states = new Map<number, JobState<Payload>>()
+
+	private listeners: Record<JobEvent, JobEventListener<Payload>[]> = {
+		settled: [],
+		cancelled: [],
+	}
+
+	addJob({ payload }: { payload: Payload }): Job<Payload> {
+		const controller = new AbortController()
+		const job: Job<Payload> = {
+			id: this.generateJobId(),
+			payload,
+			signal: controller.signal,
+		}
+		this.queue.enqueue(job)
+		this.states.set(job.id, { status: JobStatus.Pending, controller, job })
+		return job
+	}
+
+	async nextJob(signal?: AbortSignal): Promise<Job<Payload> | null> {
+		while (true) {
+			const job = await this.queue.next(signal)
+			if (!job) {
+				return null
+			}
+
+			const state = this.states.get(job.id)
+
+			if (!state || state.job !== job || state.status === JobStatus.Running) {
+				continue
+			}
+			if (state.controller.signal.aborted) {
+				this.states.delete(job.id)
+				continue
+			}
+
+			this.states.set(job.id, { status: JobStatus.Running, controller: state.controller, job })
+
+			return job
+		}
+	}
+
+	cancelJob(job: Job<unknown>): void {
+		const state = this.states.get(job.id)
+		if (state?.job === job) {
+			state?.controller.abort()
+			this.notifyListeners("cancelled", job.id)
+			this.states.delete(job.id)
+		}
+	}
+
+	markJobAsCompleted(job: Job<unknown>): void {
+		const state = this.states.get(job.id)
+		if (state?.job === job) {
+			this.notifyListeners("settled", job.id)
+			this.states.delete(job.id)
+		}
+	}
+
+	addEventListener(event: JobEvent, listener: JobEventListener<Payload>): () => void {
+		this.listeners[event].push(listener)
+		return () => {
+			this.listeners[event] = this.listeners[event].filter((l) => l !== listener)
+		}
+	}
+
+	private generateJobId(): number {
+		let id: number
+		do {
+			id = Math.floor(Math.random() * 1000000)
+		} while (this.states.has(id))
+		return id
+	}
+
+	private notifyListeners(event: JobEvent, id: number): void {
+		const job = this.states.get(id)?.job
+		if (job) {
+			this.listeners[event].forEach((listener) => listener(job))
+		}
+	}
+}
--- a/apps/freya-backend/src/lib/queue.ts
+++ b/apps/freya-backend/src/lib/queue.ts
@@ -0,0 +1,69 @@
+interface Item<T> {
+	value: T
+	next: Item<T> | null
+}
+
+export class Queue<T> {
+	private front: Item<T> | null = null
+	private back: Item<T> | null = null
+	private waiters: Array<(value: T) => void> = []
+
+	enqueue(value: T): void {
+		const waiter = this.waiters.shift()
+		if (waiter) {
+			waiter(value)
+			return
+		}
+
+		const newItem: Item<T> = { value, next: null }
+		if (this.back) {
+			this.back.next = newItem
+		} else {
+			this.front = newItem
+		}
+		this.back = newItem
+	}
+
+	dequeue(): T | null {
+		if (!this.front) return null
+		const value = this.front.value
+		this.front = this.front.next
+		if (!this.front) this.back = null
+		return value
+	}
+
+	next(signal?: AbortSignal): Promise<T | null> {
+		const value = this.dequeue()
+		if (value !== null) return Promise.resolve(value)
+
+		return new Promise((resolve) => {
+			if (signal) {
+				if (signal.aborted) {
+					resolve(null)
+				} else {
+					let _resolve: (v: T) => void
+
+					const onAbort = () => {
+						this.waiters = this.waiters.filter((w) => w !== _resolve)
+						resolve(null)
+					}
+
+					signal.addEventListener(
+						"abort",
+						onAbort,
+						{ once: true },
+					)
+
+					_resolve = (v: T) => {
+						signal.removeEventListener("abort", onAbort)
+						resolve(v)
+					}
+
+					this.waiters.push(_resolve)
+				}
+			} else {
+				this.waiters.push(resolve)
+			}
+		})
+	}
+}
--- a/apps/freya-backend/src/lib/worker.ts
+++ b/apps/freya-backend/src/lib/worker.ts
@@ -0,0 +1,51 @@
+import type { Job, JobRegistry } from "./job"
+import type { Queue } from "./queue"
+
+export interface JobExecutor<JobPayload> {
+	execute(job: Job<JobPayload>): Promise<void>
+}
+
+export interface WorkerConfig<Job> {
+	concurrency: number
+	registry: JobRegistry<Job>
+	runner: JobExecutor<Job>
+	signal: AbortSignal
+}
+
+export class Worker<Job> {
+	private concurrency: number
+	private registry: JobRegistry<Job>
+	private runner: JobExecutor<Job>
+	private signal: AbortSignal
+
+	constructor({ concurrency, registry, runner, signal }: WorkerConfig<Job>) {
+		this.concurrency = concurrency
+		this.registry = registry
+		this.runner = runner
+		this.signal = signal
+	}
+
+	start() {
+		if (this.signal.aborted) return
+		for (let i = 0; i < this.concurrency; i++) {
+			void this.pollJobFromRegistry()
+		}
+	}
+
+	private async pollJobFromRegistry() {
+		while (!this.signal.aborted) {
+			const job = await this.registry.nextJob(this.signal)
+			if (!job) {
+				return
+			}
+
+			try {
+				await this.runner.execute(job)
+			} catch {
+				// TODO: handle logging of job execution errors
+			} finally {
+				this.registry.markJobAsCompleted(job)
+			}
+		}
+	}
+}
--- a/apps/freya-backend/src/notification/notification-central.ts
+++ b/apps/freya-backend/src/notification/notification-central.ts
@@ -0,0 +1,36 @@
+import type { AgentEvent } from "@freya/agent-protocol"
+
+export interface AgentNotification {
+	kind: "agent"
+	payload: AgentEvent
+}
+
+export type NotificationPayload = AgentNotification
+export type NotificationListener = (notification: NotificationPayload) => Promise<void>
+
+export class NotificationCentral {
+	private listeners: Map<string, Set<NotificationListener>> = new Map()
+
+	registerListenerForUser(userId: string, listener: NotificationListener): () => void {
+		let listeners = this.listeners.get(userId)
+		if (!listeners) {
+			listeners = new Set()
+			this.listeners.set(userId, listeners)
+		}
+
+		listeners.add(listener)
+		return () => {
+			listeners.delete(listener)
+			if (listeners.size === 0) {
+				this.listeners.delete(userId)
+			}
+		}
+	}
+
+	async notifyUser(userId: string, notification: NotificationPayload): Promise<void> {
+		const listeners = this.listeners.get(userId)
+		if (!listeners) return
+
+		await Promise.allSettled(Array.from(listeners).map((listener) => listener(notification)))
+	}
+}
--- a/apps/freya-backend/src/server.ts
+++ b/apps/freya-backend/src/server.ts
@@ -5,6 +5,7 @@ import { createMiddleware } from "hono/factory"
 import { registerAdminHttpHandlers } from "./admin/http.ts"
 import { createQueryDebugTools } from "./agent/debug-tools.ts"
 import { registerAgentHttpHandlers, registerDebugAgentHttpHandlers } from "./agent/http.ts"
+import { AgentService } from "./agent/service.ts"
 import { agentWebSocket, registerAgentWebSocketHandlers } from "./agent/ws.ts"
 import { createRequireAdmin } from "./auth/admin-middleware.ts"
 import { registerAuthHandlers } from "./auth/http.ts"
@@ -12,6 +13,7 @@ import { createAuth } from "./auth/index.ts"
 import { createRequireSession } from "./auth/session-middleware.ts"
 import { CalDavSourceProvider } from "./caldav/provider.ts"
 import { registerConversationsHttpHandlers } from "./conversations/http.ts"
+import { DrizzleConversationStorage } from "./conversations/storage.ts"
 import { createDatabase } from "./db/index.ts"
 import { registerFeedHttpHandlers } from "./engine/http.ts"
 import { createFeedEnhancer } from "./enhancement/enhance-feed.ts"
@@ -21,6 +23,7 @@ import { CredentialEncryptor } from "./lib/crypto.ts"
 import { ensureEnv } from "./lib/env.ts"
 import { registerLocationHttpHandlers } from "./location/http.ts"
 import { LocationSourceProvider } from "./location/provider.ts"
+import { NotificationCentral } from "./notification/notification-central.ts"
 import { ReminderSourceProvider } from "./reminders/provider.ts"
 import { UserSessionManager } from "./session/index.ts"
 import { registerSourcesHttpHandlers } from "./sources/http.ts"
@@ -32,8 +35,12 @@ function main() {
 	const env = ensureEnv(process.env)

 	const { db, close: closeDb } = createDatabase(env.databaseUrl)
+	const conversationStorage = new DrizzleConversationStorage(db, false)
+
 	const auth = createAuth(db)

+	const abortController = new AbortController()
+
 	const feedEnhancer = createFeedEnhancer({
 		client: createLlmClient({
 			apiKey: env.openrouterApiKey,
@@ -73,6 +80,15 @@ function main() {
 		console.warn("[query] PI_API_KEY or OPENROUTER_API_KEY not set — query agent unavailable")
 	}

+	const notificationCentral = new NotificationCentral()
+
+	const agentService = new AgentService({
+		notificationCentral,
+		storage: conversationStorage,
+		userSessionManager: sessionManager,
+		signal: abortController.signal,
+	})
+
 	const app = new Hono()

 	const isDev = process.env.NODE_ENV !== "production"
@@ -141,17 +157,22 @@ function main() {
 	registerAdminHttpHandlers(app, { sessionManager, adminMiddleware, db })

 	registerAgentWebSocketHandlers(app, {
-		sessionManager,
+		agentService,
+		notificationCentral,
+		storage: conversationStorage,
 		authSessionMiddleware,
 		corsMiddleware: agentWebSocketCorsMiddleware,
 	})

 	process.on("SIGTERM", async () => {
 		sessionManager.dispose()
+		abortController.abort()
 		await closeDb()
 		process.exit(0)
 	})

+	agentService.start()
+
 	return app
 }

--- a/apps/freya-backend/src/session/user-session-manager.test.ts
+++ b/apps/freya-backend/src/session/user-session-manager.test.ts
@@ -120,7 +120,7 @@ mock.module("../sources/user-sources.ts", () => ({
 	}),
 }))

-mock.module("../conversations/storage.ts", () => ({
+mock.module("../conversations/db-storage.ts", () => ({
 	conversations: (_db: Database, userId: string) => ({
 		async getOrCreateConversation(): Promise<{ id: string }> {
 			mockConversationCalls.push({ type: "getOrCreate", userId })
--- a/apps/freya-backend/src/session/user-session-manager.ts
+++ b/apps/freya-backend/src/session/user-session-manager.ts
@@ -8,7 +8,7 @@ import type { FeedEnhancer } from "../enhancement/enhance-feed.ts"
 import type { CredentialEncryptor } from "../lib/crypto.ts"
 import type { FeedSourceProvider } from "./feed-source-provider.ts"

-import { conversations } from "../conversations/storage.ts"
+import { conversations } from "../conversations/db-storage.ts"
 import {
 	CredentialStorageUnavailableError,
 	InvalidSourceConfigError,
--- a/apps/freya-backend/src/session/user-session.ts
+++ b/apps/freya-backend/src/session/user-session.ts
@@ -263,18 +263,12 @@ export class UserSession {
 		const conversation = await conversationStorage.getOrCreateConversation()
 		const entries = await conversationStorage.listEntries(conversation.id)

-		this.queryAgent = new ConversationRecordingQueryAgent({
-			agent: new PiQueryAgent({
-				toolbox: this.toolbox,
-				apiKey: this.agentConfig?.apiKey,
-				cwd: this.agentConfig?.cwd,
-				systemPrompt: this.agentConfig?.systemPrompt,
-				initialEntries: entries,
-			}),
-			storage: conversationStorage,
-			defaultConversationId: conversation.id,
-			modelProvider: PI_MODEL_PROVIDER,
-			modelId: PI_MODEL_ID,
+		this.queryAgent = new PiQueryAgent({
+			toolbox: this.toolbox,
+			apiKey: this.agentConfig?.apiKey,
+			cwd: this.agentConfig?.cwd,
+			systemPrompt: this.agentConfig?.systemPrompt,
+			initialEntries: entries,
 		})
 	}

--- a/apps/freya-backend/src/sources/http.test.ts
+++ b/apps/freya-backend/src/sources/http.test.ts
@@ -128,7 +128,7 @@ mock.module("../sources/user-sources.ts", () => ({
 	},
 }))

-mock.module("../conversations/storage.ts", () => ({
+mock.module("../conversations/db-storage.ts", () => ({
 	conversations: (_db: Database, userId: string) => ({
 		async getOrCreateConversation() {
 			return { id: `conversation-${userId}` }