feat: add rich run timeline backend

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

HANDOVER.md

@@ -0,0 +1,205 @@
+# Rich run timeline handover
+
+This change implements the backend half of the `Rich run timeline` roadmap item and leaves the actual timeline UI/UX for the next agent.
+
+## What is done
+
+- Persisted structured run history on every `SessionRecord`
+- Added a shared run/timeline domain model for durable per-run metadata and ordered timeline events
+- Started a new run record whenever `sendSessionMessage(...)` kicks off a turn
+- Grouped streamed assistant output into a single timeline message event keyed by `messageId`
+- Persisted timeline updates during agent activity, message streaming, completion, and failure
+- Added explicit handoff source metadata so the future UI can draw source/target handoff edges
+- Added a live `run-updated` session event so the renderer can receive timeline changes incrementally without waiting for a full workspace refresh
+- Kept duplicate-session behavior simple and safe: duplicated sessions copy transcript/tooling config but start with `runs: []`
+
+## Important files
+
+- `src/shared/domain/runTimeline.ts`
+  - New shared types and helpers:
+    - `SessionRunRecord`
+    - `RunTimelineEventRecord`
+    - `createSessionRunRecord(...)`
+    - `appendRunActivityEvent(...)`
+    - `upsertRunMessageEvent(...)`
+    - `completeSessionRunRecord(...)`
+    - `failSessionRunRecord(...)`
+- `src/shared/domain/session.ts`
+  - `SessionRecord` now includes `runs: SessionRunRecord[]`
+- `src/main/persistence/workspaceRepository.ts`
+  - Normalizes persisted `session.runs`
+- `src/main/EryxAppService.ts`
+  - Creates and updates run records during turn execution
+  - Emits live `run-updated` session events
+- `src/shared/domain/event.ts`
+  - Added session event kind `run-updated`
+  - Added optional `run` payload on `SessionEventRecord`
+- `src/renderer/lib/sessionWorkspace.ts`
+  - Applies `run-updated` events by replacing/inserting the full run snapshot
+- `src/shared/contracts/sidecar.ts`
+  - `AgentActivityEvent` now carries optional `sourceAgentId` / `sourceAgentName`
+- `sidecar/src/Eryx.AgentHost/Contracts/ProtocolModels.cs`
+  - C# DTO mirror for the new handoff source fields
+- `sidecar/src/Eryx.AgentHost/Services/CopilotWorkflowRunner.cs`
+  - Handoff activity now includes the active/source agent when available
+
+## Backend contract
+
+### Session shape
+
+Every session now has:
+
+```ts
+runs: SessionRunRecord[]
+```
+
+Runs are stored newest-first.
+
+### `SessionRunRecord`
+
+Key fields:
+
+- `id`
+- `requestId`
+- `projectId`
+- `projectPath`
+- `workspaceKind`
+- `patternId`
+- `patternName`
+- `patternMode`
+- `triggerMessageId`
+- `startedAt`
+- `completedAt?`
+- `status`
+- `agents`
+- `events`
+
+`agents` is the per-run lane metadata the UI should use for lane headers / agent grouping.
+
+### `RunTimelineEventRecord`
+
+Event kinds:
+
+- `run-started`
+- `thinking`
+- `handoff`
+- `tool-call`
+- `message`
+- `run-completed`
+- `run-failed`
+
+Useful payload fields:
+
+- `occurredAt`
+- `updatedAt?`
+- `status`
+- `agentId` / `agentName`
+- `sourceAgentId` / `sourceAgentName`
+- `targetAgentId` / `targetAgentName`
+- `toolName`
+- `messageId`
+- `content`
+- `error`
+
+### Live update event
+
+The renderer now receives:
+
+```ts
+{
+  sessionId: string;
+  kind: 'run-updated';
+  occurredAt: string;
+  run: SessionRunRecord;
+}
+```
+
+This is a full run snapshot, not a delta patch. The reducer already replaces/upserts the run for the selected session.
+
+## Current runtime behavior
+
+### Run start
+
+`sendSessionMessage(...)` now:
+
+1. appends the user message
+2. creates a new `SessionRunRecord`
+3. persists the workspace
+4. starts the turn
+
+The initial run contains a `run-started` event pointing at `triggerMessageId`.
+
+### Thinking / handoff / tool activity
+
+Agent activity events now append timeline entries:
+
+- `thinking`
+- `handoff`
+- `tool-call`
+
+For handoffs, the backend now stores both source and target when the source agent is known.
+
+### Streamed assistant output
+
+Message streaming is grouped into one `message` event per `messageId`.
+
+During streaming:
+
+- the existing message event is updated in place
+- `status` stays `running`
+- `content` holds the latest snapshot
+- `updatedAt` advances
+
+On completion:
+
+- the same event becomes `status: 'completed'`
+- final content is persisted
+
+### Run completion / failure
+
+Successful runs append `run-completed`.
+
+Failed runs append `run-failed` and also mark any still-running message events as errored.
+
+## Notes for the UI/UX agent
+
+You do **not** need new IPC or backend endpoints for the first timeline UI pass.
+
+Use:
+
+- `session.runs` for initial render / reload
+- live `run-updated` session events for in-flight changes
+
+Suggested UI plan:
+
+1. Replace or reframe the current agent-activity tiles around the run model instead of mixing unrelated tiles together.
+2. Show runs newest-first in the side panel.
+3. Inside a run, render a vertical timeline ordered by `events[]`.
+4. Use `agents[]` to build per-agent lanes or grouped headers.
+5. Render `message` events as the coherent answer step for streamed assistant output.
+6. Use `messageId` and `triggerMessageId` for jump-to-message actions.
+7. Use `agentId`, `sourceAgentId`, and `targetAgentId` for jump-to-agent / handoff visuals.
+
+## UX-specific suggestions
+
+- `run-started`: compact start card linked to the triggering user message
+- `thinking`: lightweight state card or inline badge in the agent lane
+- `handoff`: directional edge/card from source -> target
+- `tool-call`: small tool chip/card with tool name and agent
+- `message`: the main rich output card; this is the item that should expand/collapse cleanly
+- `run-completed` / `run-failed`: footer-style terminal state card
+
+## Known limitations / open questions
+
+- There is no dedicated persisted `completed` activity event. Final assistant output plus `run-completed` is the canonical completion signal for now.
+- Tool results are not persisted yet; only tool invocation metadata is stored.
+- Pattern version metadata is not persisted yet; only `patternId`, `patternName`, and `patternMode` are captured.
+- Duplicate sessions intentionally start with empty run history. If product wants copied traces later, that needs an explicit decision.
+- Live `run-updated` events currently send the full run snapshot each time. That keeps the reducer simple; optimize later only if payload size becomes a problem.
+
+## Validation completed
+
+- `bun run typecheck`
+- `bun test`
+- `bun run sidecar:test`
+- `bun run build`

sidecar/src/Eryx.AgentHost/Contracts/ProtocolModels.cs

@@ -182,6 +182,8 @@ public sealed class AgentActivityEventDto : SidecarEventDto
     public string ActivityType { get; init; } = string.Empty;
     public string? AgentId { get; init; }
     public string? AgentName { get; init; }
+    public string? SourceAgentId { get; init; }
+    public string? SourceAgentName { get; init; }
     public string? ToolName { get; init; }
 }
 

sidecar/src/Eryx.AgentHost/Services/CopilotWorkflowRunner.cs

@@ -173,6 +173,7 @@ public sealed class CopilotWorkflowRunner : ITurnWorkflowRunner
         RunTurnCommandDto command,
         string activityType,
         AgentIdentity agent,
+        AgentIdentity? sourceAgent = null,
         string? toolName = null)
     {
         return new AgentActivityEventDto
@@ -183,6 +184,8 @@ public sealed class CopilotWorkflowRunner : ITurnWorkflowRunner
             ActivityType = activityType,
             AgentId = agent.AgentId,
             AgentName = agent.AgentName,
+            SourceAgentId = sourceAgent?.AgentId,
+            SourceAgentName = sourceAgent?.AgentName,
             ToolName = toolName,
         };
     }
@@ -197,7 +200,8 @@ public sealed class CopilotWorkflowRunner : ITurnWorkflowRunner
             return CreateActivityEvent(
                 command,
                 activityType: "handoff",
-                agent: handoffAgent);
+                agent: handoffAgent,
+                sourceAgent: activeAgent);
         }
 
         if (!activeAgent.HasValue || !TryGetToolName(requestInfo, out string toolName))

src/main/EryxAppService.ts

@@ -40,6 +40,15 @@ import {
   type ChatMessageRecord,
   type SessionRecord,
 } from '@shared/domain/session';
+import {
+  appendRunActivityEvent,
+  completeSessionRunRecord,
+  createSessionRunRecord,
+  failSessionRunRecord,
+  upsertRunMessageEvent,
+  upsertSessionRunRecord,
+  type SessionRunRecord,
+} from '@shared/domain/runTimeline';
 import {
   createSessionToolingSelection,
   type LspProfileDefinition,
@@ -318,6 +327,7 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
         ? createScratchpadSessionConfig(normalizedPattern)
         : undefined,
       tooling: createSessionToolingSelection(),
+      runs: [],
     };
 
     workspace.sessions.unshift(session);
@@ -376,28 +386,41 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
       return;
     }
 
+    const requestId = createId('turn');
+    const workspaceKind = isScratchpadProject(project) ? 'scratchpad' : 'project';
+    const occurredAt = nowIso();
+    const userMessageId = createId('msg');
     session.messages.push({
-      id: createId('msg'),
+      id: userMessageId,
       role: 'user',
       authorName: 'You',
       content: trimmed,
-      createdAt: nowIso(),
+      createdAt: occurredAt,
     });
     session.title = resolveSessionTitle(session, effectivePattern, session.messages);
     session.status = 'running';
     session.lastError = undefined;
-    session.updatedAt = nowIso();
+    session.updatedAt = occurredAt;
+    session.runs = [
+      createSessionRunRecord({
+        requestId,
+        project,
+        workspaceKind,
+        pattern: effectivePattern,
+        triggerMessageId: userMessageId,
+        startedAt: occurredAt,
+      }),
+      ...session.runs,
+    ];
 
     await this.persistAndBroadcast(workspace);
     this.emitSessionEvent({
       sessionId: session.id,
       kind: 'status',
       status: 'running',
-      occurredAt: nowIso(),
+      occurredAt,
     });
 
-    const requestId = createId('turn');
-    const workspaceKind = isScratchpadProject(project) ? 'scratchpad' : 'project';
     try {
       const responseMessages = await this.sidecar.runTurn(
         {
@@ -411,26 +434,33 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
           tooling: this.buildRunTurnToolingConfig(workspace, project, session),
         },
         async (event) => {
-          await this.applyTurnDelta(workspace, session.id, event);
+          await this.applyTurnDelta(workspace, session.id, requestId, event);
         },
-        (event) => {
+        async (event) => {
-          this.emitAgentActivity(event);
+          await this.applyAgentActivity(workspace, session.id, requestId, event);
         },
       );
 
-      this.finalizeTurn(workspace, session.id, responseMessages);
+      this.finalizeTurn(workspace, session.id, requestId, responseMessages);
       await this.persistAndBroadcast(workspace);
     } catch (error) {
+      const failedAt = nowIso();
       session.status = 'error';
       session.lastError = error instanceof Error ? error.message : String(error);
-      session.updatedAt = nowIso();
+      session.updatedAt = failedAt;
+
+      const failedRun = this.updateSessionRun(session, requestId, (run) =>
+        failSessionRunRecord(run, failedAt, session.lastError ?? 'Unknown error.'));
 
       this.emitSessionEvent({
         sessionId: session.id,
         kind: 'error',
-        occurredAt: nowIso(),
+        occurredAt: failedAt,
         error: session.lastError,
       });
+      if (failedRun) {
+        this.emitRunUpdated(session.id, failedAt, failedRun);
+      }
 
       await this.persistAndBroadcast(workspace);
     }
@@ -607,18 +637,23 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
   private async applyTurnDelta(
     workspace: WorkspaceState,
     sessionId: string,
+    requestId: string,
     event: TurnDeltaEvent,
   ): Promise<void> {
     if (event.content === undefined && event.contentDelta === undefined) {
       return;
     }
 
+    const occurredAt = nowIso();
     const session = this.requireSession(workspace, sessionId);
     const existing = session.messages.find((message) => message.id === event.messageId);
+    const content =
+      existing && event.content === undefined
+        ? mergeStreamingText(existing.content, event.contentDelta)
+        : (event.content ?? event.contentDelta);
 
     if (existing) {
-      existing.content =
+      existing.content = content;
-        event.content ?? mergeStreamingText(existing.content, event.contentDelta);
       existing.pending = true;
       existing.authorName = event.authorName;
     } else {
@@ -626,34 +661,75 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
         id: event.messageId,
         role: 'assistant',
         authorName: event.authorName,
-        content: event.content ?? event.contentDelta,
+        content,
-        createdAt: nowIso(),
+        createdAt: occurredAt,
         pending: true,
       });
     }
 
-    session.updatedAt = nowIso();
+    const nextRun = this.updateSessionRun(session, requestId, (run) =>
+      upsertRunMessageEvent(run, {
+        messageId: event.messageId,
+        occurredAt,
+        authorName: event.authorName,
+        content,
+        status: 'running',
+      }));
+
+    session.updatedAt = occurredAt;
     await this.workspaceRepository.save(workspace);
 
     this.emitSessionEvent({
       sessionId,
       kind: 'message-delta',
-      occurredAt: nowIso(),
+      occurredAt,
       messageId: event.messageId,
       authorName: event.authorName,
       contentDelta: event.contentDelta,
       content: event.content,
     });
+    if (nextRun) {
+      this.emitRunUpdated(sessionId, occurredAt, nextRun);
+    }
   }
 
-  private emitAgentActivity(event: AgentActivityEvent): void {
+  private async applyAgentActivity(
+    workspace: WorkspaceState,
+    sessionId: string,
+    requestId: string,
+    event: AgentActivityEvent,
+  ): Promise<void> {
+    const occurredAt = nowIso();
+    const session = this.requireSession(workspace, sessionId);
+    const activityType = event.activityType;
+    let nextRun: SessionRunRecord | undefined;
+    if (activityType !== 'completed') {
+      nextRun = this.updateSessionRun(session, requestId, (run) =>
+        appendRunActivityEvent(run, {
+          activityType,
+          occurredAt,
+          agentId: event.agentId,
+          agentName: event.agentName,
+          sourceAgentId: event.sourceAgentId,
+          sourceAgentName: event.sourceAgentName,
+          toolName: event.toolName,
+        }));
+    }
+    if (nextRun) {
+      session.updatedAt = occurredAt;
+      await this.workspaceRepository.save(workspace);
+      this.emitRunUpdated(sessionId, occurredAt, nextRun);
+    }
+
     this.emitSessionEvent({
-      sessionId: event.sessionId,
+      sessionId,
       kind: 'agent-activity',
-      occurredAt: nowIso(),
+      occurredAt,
       activityType: event.activityType,
       agentId: event.agentId,
       agentName: event.agentName,
+      sourceAgentId: event.sourceAgentId,
+      sourceAgentName: event.sourceAgentName,
       toolName: event.toolName,
     });
   }
@@ -683,12 +759,18 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
     });
   }
 
-  private finalizeTurn(workspace: WorkspaceState, sessionId: string, messages: ChatMessageRecord[]): void {
+  private finalizeTurn(
+    workspace: WorkspaceState,
+    sessionId: string,
+    requestId: string,
+    messages: ChatMessageRecord[],
+  ): void {
     const session = this.requireSession(workspace, sessionId);
     const pattern = this.requirePattern(workspace, session.patternId);
     const incomingIds = new Set(messages.map((message) => message.id));
 
     for (const message of messages) {
+      const occurredAt = nowIso();
       const existing = session.messages.find((current) => current.id === message.id);
       if (existing) {
         existing.authorName = message.authorName;
@@ -698,14 +780,25 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
         session.messages.push({ ...message, pending: false });
       }
 
+      const nextRun = this.updateSessionRun(session, requestId, (run) =>
+        upsertRunMessageEvent(run, {
+          messageId: message.id,
+          occurredAt,
+          authorName: message.authorName,
+          content: message.content,
+          status: 'completed',
+        }));
       this.emitSessionEvent({
         sessionId,
         kind: 'message-complete',
-        occurredAt: nowIso(),
+        occurredAt,
         messageId: message.id,
         authorName: message.authorName,
         content: message.content,
       });
+      if (nextRun) {
+        this.emitRunUpdated(sessionId, occurredAt, nextRun);
+      }
 
       this.emitCompletedActivity(sessionId, pattern, message);
     }
@@ -716,15 +809,21 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
       }
     }
 
+    const completedAt = nowIso();
     session.status = 'idle';
     session.lastError = undefined;
-    session.updatedAt = nowIso();
+    session.updatedAt = completedAt;
+    const completedRun = this.updateSessionRun(session, requestId, (run) =>
+      completeSessionRunRecord(run, completedAt));
     this.emitSessionEvent({
       sessionId,
       kind: 'status',
-      occurredAt: nowIso(),
+      occurredAt: completedAt,
       status: 'idle',
     });
+    if (completedRun) {
+      this.emitRunUpdated(sessionId, completedAt, completedRun);
+    }
   }
 
   private async persistAndBroadcast(workspace: WorkspaceState): Promise<WorkspaceState> {
@@ -835,6 +934,34 @@ export class EryxAppService extends EventEmitter<AppServiceEvents> {
     };
   }
 
+  private updateSessionRun(
+    session: SessionRecord,
+    requestId: string,
+    updater: (run: SessionRunRecord) => SessionRunRecord,
+  ): SessionRunRecord | undefined {
+    const run = session.runs.find((candidate) => candidate.requestId === requestId);
+    if (!run) {
+      return undefined;
+    }
+
+    const nextRun = updater(run);
+    if (nextRun === run) {
+      return undefined;
+    }
+
+    session.runs = upsertSessionRunRecord(session.runs, nextRun);
+    return nextRun;
+  }
+
+  private emitRunUpdated(sessionId: string, occurredAt: string, run: SessionRunRecord): void {
+    this.emitSessionEvent({
+      sessionId,
+      kind: 'run-updated',
+      occurredAt,
+      run,
+    });
+  }
+
   private emitSessionEvent(event: SessionEventRecord): void {
     this.emit('session-event', event);
   }

src/main/persistence/workspaceRepository.ts

@@ -3,6 +3,7 @@ import { mkdir } from 'node:fs/promises';
 import { createBuiltinPatterns } from '@shared/domain/pattern';
 import type { PatternDefinition } from '@shared/domain/pattern';
 import { mergeScratchpadProject } from '@shared/domain/project';
+import { normalizeSessionRunRecords } from '@shared/domain/runTimeline';
 import { normalizeSessionToolingSelection, normalizeWorkspaceSettings } from '@shared/domain/tooling';
 import { createWorkspaceSeed, type WorkspaceState } from '@shared/domain/workspace';
 import { nowIso } from '@shared/utils/ids';
@@ -62,6 +63,7 @@ export class WorkspaceRepository {
       projects,
       sessions: (stored.sessions ?? []).map((session) => ({
         ...session,
+        runs: normalizeSessionRunRecords(session.runs),
         tooling: normalizeSessionToolingSelection(session.tooling),
       })),
       settings: normalizeWorkspaceSettings(stored.settings),

src/renderer/lib/sessionWorkspace.ts

@@ -1,4 +1,5 @@
 import type { SessionEventRecord } from '@shared/domain/event';
+import { upsertSessionRunRecord } from '@shared/domain/runTimeline';
 import type { ChatMessageRecord, SessionRecord } from '@shared/domain/session';
 import type { WorkspaceState } from '@shared/domain/workspace';
 import { mergeStreamingText } from '@shared/utils/streamingText';
@@ -40,6 +41,8 @@ function applySessionEvent(session: SessionRecord, event: SessionEventRecord): S
       return applyMessageDeltaEvent(session, event);
     case 'message-complete':
       return applyMessageCompleteEvent(session, event);
+    case 'run-updated':
+      return applyRunUpdatedEvent(session, event);
     default:
       return session;
   }
@@ -160,3 +163,23 @@ function applyMessageCompleteEvent(session: SessionRecord, event: SessionEventRe
     updatedAt: event.occurredAt,
   };
 }
+
+function applyRunUpdatedEvent(session: SessionRecord, event: SessionEventRecord): SessionRecord {
+  if (!event.run) {
+    return session;
+  }
+
+  const nextRuns = upsertSessionRunRecord(session.runs, event.run);
+  if (
+    nextRuns.length === session.runs.length
+    && nextRuns.every((run, index) => run === session.runs[index])
+  ) {
+    return session;
+  }
+
+  return {
+    ...session,
+    runs: nextRuns,
+    updatedAt: event.occurredAt,
+  };
+}

src/shared/contracts/sidecar.ts

@@ -152,6 +152,8 @@ export interface AgentActivityEvent {
   activityType: AgentActivityType;
   agentId?: string;
   agentName?: string;
+  sourceAgentId?: string;
+  sourceAgentName?: string;
   toolName?: string;
 }
 

src/shared/domain/event.ts

@@ -1,3 +1,5 @@
+import type { SessionRunRecord } from '@shared/domain/runTimeline';
+
 export type SessionActivityType = 'thinking' | 'tool-calling' | 'handoff' | 'completed';
 
 export type SessionEventKind =
@@ -5,6 +7,7 @@ export type SessionEventKind =
   | 'message-delta'
   | 'message-complete'
   | 'agent-activity'
+  | 'run-updated'
   | 'error';
 
 export interface SessionEventRecord {
@@ -19,6 +22,9 @@ export interface SessionEventRecord {
   activityType?: SessionActivityType;
   agentId?: string;
   agentName?: string;
+  sourceAgentId?: string;
+  sourceAgentName?: string;
   toolName?: string;
+  run?: SessionRunRecord;
   error?: string;
 }

src/shared/domain/runTimeline.ts

@@ -0,0 +1,454 @@
+import type { PatternDefinition, ReasoningEffort } from '@shared/domain/pattern';
+import type { ProjectRecord } from '@shared/domain/project';
+import { createId } from '@shared/utils/ids';
+
+export type SessionRunStatus = 'running' | 'completed' | 'error';
+export type SessionRunWorkspaceKind = 'project' | 'scratchpad';
+export type RunTimelineEventKind =
+  | 'run-started'
+  | 'thinking'
+  | 'handoff'
+  | 'tool-call'
+  | 'message'
+  | 'run-completed'
+  | 'run-failed';
+export type RunTimelineEventStatus = 'running' | 'completed' | 'error';
+
+export interface RunTimelineAgentRecord {
+  agentId: string;
+  agentName: string;
+  model: string;
+  reasoningEffort?: ReasoningEffort;
+}
+
+export interface RunTimelineEventRecord {
+  id: string;
+  kind: RunTimelineEventKind;
+  occurredAt: string;
+  updatedAt?: string;
+  status: RunTimelineEventStatus;
+  agentId?: string;
+  agentName?: string;
+  sourceAgentId?: string;
+  sourceAgentName?: string;
+  targetAgentId?: string;
+  targetAgentName?: string;
+  toolName?: string;
+  messageId?: string;
+  content?: string;
+  error?: string;
+}
+
+export interface SessionRunRecord {
+  id: string;
+  requestId: string;
+  projectId: string;
+  projectPath: string;
+  workspaceKind: SessionRunWorkspaceKind;
+  patternId: string;
+  patternName: string;
+  patternMode: PatternDefinition['mode'];
+  triggerMessageId: string;
+  startedAt: string;
+  completedAt?: string;
+  status: SessionRunStatus;
+  agents: RunTimelineAgentRecord[];
+  events: RunTimelineEventRecord[];
+}
+
+export interface CreateSessionRunRecordInput {
+  requestId: string;
+  project: Pick<ProjectRecord, 'id' | 'path'>;
+  workspaceKind: SessionRunWorkspaceKind;
+  pattern: Pick<PatternDefinition, 'id' | 'name' | 'mode' | 'agents'>;
+  triggerMessageId: string;
+  startedAt: string;
+}
+
+export interface AppendRunActivityEventInput {
+  activityType: 'thinking' | 'tool-calling' | 'handoff';
+  occurredAt: string;
+  agentId?: string;
+  agentName?: string;
+  sourceAgentId?: string;
+  sourceAgentName?: string;
+  toolName?: string;
+}
+
+export interface UpsertRunMessageEventInput {
+  messageId: string;
+  occurredAt: string;
+  authorName?: string;
+  content?: string;
+  status: RunTimelineEventStatus;
+  error?: string;
+}
+
+function normalizeOptionalString(value: string | undefined): string | undefined {
+  const trimmed = value?.trim();
+  return trimmed ? trimmed : undefined;
+}
+
+function normalizeRunTimelineAgent(
+  agent: RunTimelineAgentRecord,
+): RunTimelineAgentRecord | undefined {
+  const agentId = normalizeOptionalString(agent.agentId);
+  const agentName = normalizeOptionalString(agent.agentName);
+  const model = normalizeOptionalString(agent.model);
+  if (!agentId || !agentName || !model) {
+    return undefined;
+  }
+
+  return {
+    agentId,
+    agentName,
+    model,
+    reasoningEffort: agent.reasoningEffort,
+  };
+}
+
+function normalizeRunTimelineEvent(
+  event: RunTimelineEventRecord,
+): RunTimelineEventRecord | undefined {
+  const id = normalizeOptionalString(event.id);
+  const occurredAt = normalizeOptionalString(event.occurredAt);
+  if (!id || !occurredAt) {
+    return undefined;
+  }
+
+  return {
+    id,
+    kind: event.kind,
+    occurredAt,
+    updatedAt: normalizeOptionalString(event.updatedAt),
+    status: event.status,
+    agentId: normalizeOptionalString(event.agentId),
+    agentName: normalizeOptionalString(event.agentName),
+    sourceAgentId: normalizeOptionalString(event.sourceAgentId),
+    sourceAgentName: normalizeOptionalString(event.sourceAgentName),
+    targetAgentId: normalizeOptionalString(event.targetAgentId),
+    targetAgentName: normalizeOptionalString(event.targetAgentName),
+    toolName: normalizeOptionalString(event.toolName),
+    messageId: normalizeOptionalString(event.messageId),
+    content: event.content,
+    error: normalizeOptionalString(event.error),
+  };
+}
+
+function resolveRunTimelineAgent(
+  run: SessionRunRecord,
+  agentId?: string,
+  agentName?: string,
+): Pick<RunTimelineEventRecord, 'agentId' | 'agentName'> {
+  const normalizedAgentId = normalizeOptionalString(agentId);
+  const normalizedAgentName = normalizeOptionalString(agentName);
+
+  if (normalizedAgentId) {
+    const matchedAgent = run.agents.find((agent) => agent.agentId === normalizedAgentId);
+    if (matchedAgent) {
+      return {
+        agentId: matchedAgent.agentId,
+        agentName: matchedAgent.agentName,
+      };
+    }
+  }
+
+  if (normalizedAgentName) {
+    const matchedAgent = run.agents.find((agent) => agent.agentName === normalizedAgentName);
+    if (matchedAgent) {
+      return {
+        agentId: matchedAgent.agentId,
+        agentName: matchedAgent.agentName,
+      };
+    }
+  }
+
+  return {
+    agentId: normalizedAgentId,
+    agentName: normalizedAgentName,
+  };
+}
+
+function appendRunTimelineEvent(
+  run: SessionRunRecord,
+  event: Omit<RunTimelineEventRecord, 'id'> & { id?: string },
+): SessionRunRecord {
+  const nextEvent = normalizeRunTimelineEvent({
+    id: event.id ?? createId('run-event'),
+    ...event,
+  });
+  if (!nextEvent) {
+    return run;
+  }
+
+  return {
+    ...run,
+    events: [...run.events, nextEvent],
+  };
+}
+
+function settleOpenMessageEvents(
+  run: SessionRunRecord,
+  status: Extract<RunTimelineEventStatus, 'completed' | 'error'>,
+  occurredAt: string,
+  error?: string,
+): SessionRunRecord {
+  let changed = false;
+  const normalizedError = normalizeOptionalString(error);
+  const nextEvents = run.events.map((event) => {
+    if (event.kind !== 'message' || event.status !== 'running') {
+      return event;
+    }
+
+    changed = true;
+    return {
+      ...event,
+      status,
+      updatedAt: occurredAt,
+      error: normalizedError,
+    };
+  });
+
+  if (!changed) {
+    return run;
+  }
+
+  return {
+    ...run,
+    events: nextEvents,
+  };
+}
+
+export function createSessionRunRecord(input: CreateSessionRunRecordInput): SessionRunRecord {
+  return {
+    id: createId('run'),
+    requestId: input.requestId,
+    projectId: input.project.id,
+    projectPath: input.project.path,
+    workspaceKind: input.workspaceKind,
+    patternId: input.pattern.id,
+    patternName: input.pattern.name,
+    patternMode: input.pattern.mode,
+    triggerMessageId: input.triggerMessageId,
+    startedAt: input.startedAt,
+    status: 'running',
+    completedAt: undefined,
+    agents: input.pattern.agents
+      .map((agent): RunTimelineAgentRecord => ({
+        agentId: agent.id,
+        agentName: agent.name,
+        model: agent.model,
+        reasoningEffort: agent.reasoningEffort,
+      }))
+      .flatMap((agent) => {
+        const normalized = normalizeRunTimelineAgent(agent);
+        return normalized ? [normalized] : [];
+      }),
+    events: [
+      {
+        id: createId('run-event'),
+        kind: 'run-started',
+        occurredAt: input.startedAt,
+        status: 'completed',
+        messageId: input.triggerMessageId,
+      },
+    ],
+  };
+}
+
+export function normalizeSessionRunRecords(
+  runs: readonly SessionRunRecord[] | undefined,
+): SessionRunRecord[] {
+  if (!runs || runs.length === 0) {
+    return [];
+  }
+
+  return runs.flatMap((run) => {
+    const id = normalizeOptionalString(run.id);
+    const requestId = normalizeOptionalString(run.requestId);
+    const projectId = normalizeOptionalString(run.projectId);
+    const projectPath = normalizeOptionalString(run.projectPath);
+    const patternId = normalizeOptionalString(run.patternId);
+    const patternName = normalizeOptionalString(run.patternName);
+    const triggerMessageId = normalizeOptionalString(run.triggerMessageId);
+    const startedAt = normalizeOptionalString(run.startedAt);
+    if (!id || !requestId || !projectId || !projectPath || !patternId || !patternName || !triggerMessageId || !startedAt) {
+      return [];
+    }
+
+    return [
+      {
+        id,
+        requestId,
+        projectId,
+        projectPath,
+        workspaceKind: run.workspaceKind === 'scratchpad' ? 'scratchpad' : 'project',
+        patternId,
+        patternName,
+        patternMode: run.patternMode,
+        triggerMessageId,
+        startedAt,
+        completedAt: normalizeOptionalString(run.completedAt),
+        status: run.status === 'error' ? 'error' : run.status === 'running' ? 'running' : 'completed',
+        agents: run.agents.flatMap((agent) => {
+          const normalized = normalizeRunTimelineAgent(agent);
+          return normalized ? [normalized] : [];
+        }),
+        events: run.events.flatMap((event) => {
+          const normalized = normalizeRunTimelineEvent(event);
+          return normalized ? [normalized] : [];
+        }),
+      },
+    ];
+  });
+}
+
+export function upsertSessionRunRecord(
+  runs: readonly SessionRunRecord[],
+  nextRun: SessionRunRecord,
+): SessionRunRecord[] {
+  const runIndex = runs.findIndex((run) => run.id === nextRun.id);
+  if (runIndex < 0) {
+    return [nextRun, ...runs];
+  }
+
+  const nextRuns = runs.slice();
+  nextRuns[runIndex] = nextRun;
+  return nextRuns;
+}
+
+export function appendRunActivityEvent(
+  run: SessionRunRecord,
+  input: AppendRunActivityEventInput,
+): SessionRunRecord {
+  switch (input.activityType) {
+    case 'thinking': {
+      const agent = resolveRunTimelineAgent(run, input.agentId, input.agentName);
+      return appendRunTimelineEvent(run, {
+        kind: 'thinking',
+        occurredAt: input.occurredAt,
+        status: 'completed',
+        ...agent,
+      });
+    }
+    case 'tool-calling': {
+      const agent = resolveRunTimelineAgent(run, input.agentId, input.agentName);
+      return appendRunTimelineEvent(run, {
+        kind: 'tool-call',
+        occurredAt: input.occurredAt,
+        status: 'completed',
+        ...agent,
+        toolName: normalizeOptionalString(input.toolName),
+      });
+    }
+    case 'handoff': {
+      const sourceAgent = resolveRunTimelineAgent(run, input.sourceAgentId, input.sourceAgentName);
+      const targetAgent = resolveRunTimelineAgent(run, input.agentId, input.agentName);
+      return appendRunTimelineEvent(run, {
+        kind: 'handoff',
+        occurredAt: input.occurredAt,
+        status: 'completed',
+        agentId: sourceAgent.agentId,
+        agentName: sourceAgent.agentName,
+        sourceAgentId: sourceAgent.agentId,
+        sourceAgentName: sourceAgent.agentName,
+        targetAgentId: targetAgent.agentId,
+        targetAgentName: targetAgent.agentName,
+      });
+    }
+  }
+}
+
+export function upsertRunMessageEvent(
+  run: SessionRunRecord,
+  input: UpsertRunMessageEventInput,
+): SessionRunRecord {
+  const messageId = normalizeOptionalString(input.messageId);
+  if (!messageId) {
+    return run;
+  }
+
+  const author = resolveRunTimelineAgent(run, undefined, input.authorName);
+  const existingIndex = run.events.findIndex((event) => event.kind === 'message' && event.messageId === messageId);
+  const normalizedError = normalizeOptionalString(input.error);
+
+  if (existingIndex < 0) {
+    return appendRunTimelineEvent(run, {
+      kind: 'message',
+      occurredAt: input.occurredAt,
+      updatedAt: input.occurredAt,
+      status: input.status,
+      messageId,
+      content: input.content,
+      error: normalizedError,
+      ...author,
+    });
+  }
+
+  const existingEvent = run.events[existingIndex];
+  const nextEvent: RunTimelineEventRecord = {
+    ...existingEvent,
+    agentId: existingEvent.agentId ?? author.agentId,
+    agentName: existingEvent.agentName ?? author.agentName,
+    updatedAt: input.occurredAt,
+    status: input.status,
+    content: input.content ?? existingEvent.content,
+    error: normalizedError,
+  };
+
+  if (
+    nextEvent.agentId === existingEvent.agentId
+    && nextEvent.agentName === existingEvent.agentName
+    && nextEvent.updatedAt === existingEvent.updatedAt
+    && nextEvent.status === existingEvent.status
+    && nextEvent.content === existingEvent.content
+    && nextEvent.error === existingEvent.error
+  ) {
+    return run;
+  }
+
+  const nextEvents = run.events.slice();
+  nextEvents[existingIndex] = nextEvent;
+  return {
+    ...run,
+    events: nextEvents,
+  };
+}
+
+export function completeSessionRunRecord(
+  run: SessionRunRecord,
+  completedAt: string,
+): SessionRunRecord {
+  const settledRun = settleOpenMessageEvents(run, 'completed', completedAt);
+  const completedRun: SessionRunRecord = {
+    ...settledRun,
+    status: 'completed',
+    completedAt,
+  };
+
+  return appendRunTimelineEvent(completedRun, {
+    kind: 'run-completed',
+    occurredAt: completedAt,
+    status: 'completed',
+  });
+}
+
+export function failSessionRunRecord(
+  run: SessionRunRecord,
+  failedAt: string,
+  error: string,
+): SessionRunRecord {
+  const settledRun = settleOpenMessageEvents(run, 'error', failedAt, error);
+  const failedRun: SessionRunRecord = {
+    ...settledRun,
+    status: 'error',
+    completedAt: failedAt,
+  };
+
+  return appendRunTimelineEvent(failedRun, {
+    kind: 'run-failed',
+    occurredAt: failedAt,
+    status: 'error',
+    error,
+  });
+}

src/shared/domain/session.ts

@@ -4,6 +4,7 @@ import {
   normalizeSessionToolingSelection,
   type SessionToolingSelection,
 } from '@shared/domain/tooling';
+import type { SessionRunRecord } from '@shared/domain/runTimeline';
 
 export type ChatRole = 'system' | 'user' | 'assistant';
 export type SessionStatus = 'idle' | 'running' | 'error';
@@ -38,6 +39,7 @@ export interface SessionRecord {
   lastError?: string;
   scratchpadConfig?: ScratchpadSessionConfig;
   tooling?: SessionToolingSelection;
+  runs: SessionRunRecord[];
 }
 
 export function resolveSessionTitle(

src/shared/domain/sessionLibrary.ts

@@ -181,6 +181,7 @@ export function duplicateSessionRecord(
           enabledLspProfileIds: [...session.tooling.enabledLspProfileIds],
         }
       : undefined,
+    runs: [],
     messages: session.messages.map((message): ChatMessageRecord => ({
       ...message,
       pending: false,

tests/renderer/messagePhase.test.ts

@@ -16,6 +16,7 @@ function createSession(
     updatedAt: '2026-03-23T00:00:00.000Z',
     status,
     messages,
+    runs: [],
   };
 }
 

tests/renderer/sessionWorkspace.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, test } from 'bun:test';
 
 import { applySessionEventWorkspace } from '@renderer/lib/sessionWorkspace';
 import type { SessionEventRecord } from '@shared/domain/event';
+import type { SessionRunRecord } from '@shared/domain/runTimeline';
 import { createWorkspaceSettings } from '@shared/domain/tooling';
 import type { WorkspaceState } from '@shared/domain/workspace';
 
@@ -21,6 +22,7 @@ describe('session workspace helpers', () => {
           updatedAt: '2026-03-23T00:00:00.000Z',
           status: 'idle',
           messages: [],
+          runs: [],
         },
       ],
       selectedSessionId: 'session-1',
@@ -185,6 +187,47 @@ describe('session workspace helpers', () => {
     });
   });
 
+  test('applies live run snapshots without waiting for a workspace refresh', () => {
+    const run: SessionRunRecord = {
+      id: 'run-1',
+      requestId: 'turn-1',
+      projectId: 'project-1',
+      projectPath: 'C:\\workspace\\alpha',
+      workspaceKind: 'project',
+      patternId: 'pattern-1',
+      patternName: 'Sequential Review',
+      patternMode: 'sequential',
+      triggerMessageId: 'msg-user-1',
+      startedAt: '2026-03-23T00:00:01.000Z',
+      status: 'running',
+      agents: [
+        {
+          agentId: 'agent-1',
+          agentName: 'Writer',
+          model: 'gpt-5.4',
+        },
+      ],
+      events: [
+        {
+          id: 'run-event-1',
+          kind: 'run-started',
+          occurredAt: '2026-03-23T00:00:01.000Z',
+          status: 'completed',
+          messageId: 'msg-user-1',
+        },
+      ],
+    };
+
+    const updated = applySessionEventWorkspace(createWorkspace(), {
+      sessionId: 'session-1',
+      kind: 'run-updated',
+      occurredAt: '2026-03-23T00:00:01.000Z',
+      run,
+    } satisfies SessionEventRecord);
+
+    expect(updated?.sessions[0].runs).toEqual([run]);
+  });
+
   test('ignores events for unknown sessions', () => {
     const workspace = createWorkspace();
     expect(

tests/shared/runTimeline.test.ts

@@ -0,0 +1,171 @@
+import { describe, expect, test } from 'bun:test';
+
+import type { PatternDefinition } from '@shared/domain/pattern';
+import {
+  appendRunActivityEvent,
+  completeSessionRunRecord,
+  createSessionRunRecord,
+  normalizeSessionRunRecords,
+  upsertRunMessageEvent,
+} from '@shared/domain/runTimeline';
+import type { ProjectRecord } from '@shared/domain/project';
+
+function createPattern(): PatternDefinition {
+  return {
+    id: 'pattern-sequential',
+    name: 'Sequential Trio Review',
+    description: 'Sequential handoff review flow.',
+    mode: 'sequential',
+    availability: 'available',
+    maxIterations: 1,
+    agents: [
+      {
+        id: 'agent-writer',
+        name: 'Writer',
+        description: 'Writes the draft.',
+        instructions: 'Write.',
+        model: 'gpt-5.4',
+      },
+      {
+        id: 'agent-reviewer',
+        name: 'Reviewer',
+        description: 'Reviews the draft.',
+        instructions: 'Review.',
+        model: 'claude-sonnet-4.5',
+      },
+    ],
+    createdAt: '2026-03-23T00:00:00.000Z',
+    updatedAt: '2026-03-23T00:00:00.000Z',
+  };
+}
+
+function createProject(): ProjectRecord {
+  return {
+    id: 'project-1',
+    name: 'alpha',
+    path: 'C:\\workspace\\alpha',
+    addedAt: '2026-03-23T00:00:00.000Z',
+  };
+}
+
+describe('run timeline helpers', () => {
+  test('creates a persistent run record with agent lanes and a trigger event', () => {
+    const run = createSessionRunRecord({
+      requestId: 'turn-1',
+      project: createProject(),
+      workspaceKind: 'project',
+      pattern: createPattern(),
+      triggerMessageId: 'msg-user-1',
+      startedAt: '2026-03-23T00:00:01.000Z',
+    });
+
+    expect(run).toMatchObject({
+      requestId: 'turn-1',
+      projectId: 'project-1',
+      projectPath: 'C:\\workspace\\alpha',
+      patternId: 'pattern-sequential',
+      patternName: 'Sequential Trio Review',
+      patternMode: 'sequential',
+      triggerMessageId: 'msg-user-1',
+      status: 'running',
+    });
+    expect(run.agents).toEqual([
+      {
+        agentId: 'agent-writer',
+        agentName: 'Writer',
+        model: 'gpt-5.4',
+        reasoningEffort: undefined,
+      },
+      {
+        agentId: 'agent-reviewer',
+        agentName: 'Reviewer',
+        model: 'claude-sonnet-4.5',
+        reasoningEffort: undefined,
+      },
+    ]);
+    expect(run.events[0]).toMatchObject({
+      kind: 'run-started',
+      status: 'completed',
+      messageId: 'msg-user-1',
+    });
+  });
+
+  test('records grouped message steps and settles the run on completion', () => {
+    const baseRun = createSessionRunRecord({
+      requestId: 'turn-1',
+      project: createProject(),
+      workspaceKind: 'project',
+      pattern: createPattern(),
+      triggerMessageId: 'msg-user-1',
+      startedAt: '2026-03-23T00:00:01.000Z',
+    });
+
+    const streamingRun = upsertRunMessageEvent(baseRun, {
+      messageId: 'msg-assistant-1',
+      authorName: 'Writer',
+      content: 'Draft',
+      occurredAt: '2026-03-23T00:00:02.000Z',
+      status: 'running',
+    });
+
+    const completedRun = completeSessionRunRecord(
+      upsertRunMessageEvent(streamingRun, {
+        messageId: 'msg-assistant-1',
+        authorName: 'Writer',
+        content: 'Draft polished into the final answer.',
+        occurredAt: '2026-03-23T00:00:03.000Z',
+        status: 'completed',
+      }),
+      '2026-03-23T00:00:04.000Z',
+    );
+
+    const messageEvent = completedRun.events.find((event) => event.kind === 'message');
+    expect(messageEvent).toMatchObject({
+      messageId: 'msg-assistant-1',
+      agentId: 'agent-writer',
+      agentName: 'Writer',
+      content: 'Draft polished into the final answer.',
+      status: 'completed',
+      updatedAt: '2026-03-23T00:00:03.000Z',
+    });
+    expect(completedRun.status).toBe('completed');
+    expect(completedRun.completedAt).toBe('2026-03-23T00:00:04.000Z');
+    expect(completedRun.events.at(-1)).toMatchObject({
+      kind: 'run-completed',
+      status: 'completed',
+    });
+  });
+
+  test('captures handoffs with explicit source and target agents', () => {
+    const run = appendRunActivityEvent(
+      createSessionRunRecord({
+        requestId: 'turn-1',
+        project: createProject(),
+        workspaceKind: 'project',
+        pattern: createPattern(),
+        triggerMessageId: 'msg-user-1',
+        startedAt: '2026-03-23T00:00:01.000Z',
+      }),
+      {
+        activityType: 'handoff',
+        occurredAt: '2026-03-23T00:00:02.000Z',
+        sourceAgentId: 'agent-writer',
+        agentId: 'agent-reviewer',
+      },
+    );
+
+    expect(run.events.at(-1)).toMatchObject({
+      kind: 'handoff',
+      agentId: 'agent-writer',
+      agentName: 'Writer',
+      sourceAgentId: 'agent-writer',
+      sourceAgentName: 'Writer',
+      targetAgentId: 'agent-reviewer',
+      targetAgentName: 'Reviewer',
+    });
+  });
+
+  test('normalizes missing run collections to an empty array', () => {
+    expect(normalizeSessionRunRecords(undefined)).toEqual([]);
+  });
+});

tests/shared/session.test.ts

@@ -51,6 +51,7 @@ function createSession(overrides?: Partial<SessionRecord>): SessionRecord {
     updatedAt: '2026-03-23T00:00:00.000Z',
     status: 'idle',
     messages: [],
+    runs: [],
     ...overrides,
   };
 }

tests/shared/sessionLibrary.test.ts

@@ -59,6 +59,7 @@ function createSession(overrides?: Partial<SessionRecord>): SessionRecord {
         createdAt: '2026-03-23T00:00:00.000Z',
       },
     ],
+    runs: [],
     ...overrides,
   };
 }
@@ -148,6 +149,7 @@ describe('session library helpers', () => {
       updatedAt: '2026-03-23T00:07:00.000Z',
     });
     expect(session.messages[0]?.pending).toBe(false);
+    expect(session.runs).toEqual([]);
   });
 
   test('searches across session title, messages, projects, and patterns', () => {