# Agent Runs Events and History Route Protocol

> **NOTE**: This document is the single source of truth for agent runs event streaming and history snapshot routes.

## Overview

Defines the transport format for:

- `POST /api/v1/agent/runs`
- `GET /api/v1/agent/runs/{thread_id}/events`
- `GET /api/v1/agent/history`
- `GET /api/v1/agent/attachments/signed-url`

## Version

- **Current**: `1.0`
- **Status**: Draft (pending full backend/frontend alignment)

---

## Route Semantics

### `GET /api/v1/agent/history`

- Unified history endpoint.
- Query params:
  - `threadId` (optional): target thread id.
  - `before` (optional, `YYYY-MM-DD`): paginate by day.
- Behavior:
  - With `threadId`: returns that thread's day snapshot.
  - Without `threadId`: returns latest available thread snapshot for current user.

### `GET /api/v1/agent/attachments/signed-url`

- Generate temporary signed URL for attachment rendering.
- Query params:
  - `bucket` (required)
  - `path` (required)
- Scope rule:
  - `bucket` must match current storage bucket.
  - `path` must be within current user prefix `agent-inputs/{user_id}/`.

---

## SSE Envelope (`/events`)

`GET /api/v1/agent/runs/{thread_id}/events` uses `text/event-stream`.

Each SSE frame format:

```text
id: <stream-id>
event: <EVENT_TYPE>
data: <JSON payload>

```

---

## Event Type Set

- `RUN_STARTED`
- `STEP_STARTED`
- `STEP_FINISHED`
- `TEXT_MESSAGE_START`
- `TEXT_MESSAGE_CONTENT`
- `TEXT_MESSAGE_END`
- `TOOL_CALL_RESULT`
- `RUN_FINISHED`
- `RUN_ERROR`

---

## Common Event Fields

```typescript
interface EventBase {
  type: string;
  threadId: string;
  runId?: string;
}
```

---

## Event Payload Schemas

### Run Lifecycle

```typescript
interface RunStartedEvent extends EventBase {
  type: "RUN_STARTED";
  runId: string;
}

interface RunFinishedEvent extends EventBase {
  type: "RUN_FINISHED";
  runId: string;
}

interface RunErrorEvent extends EventBase {
  type: "RUN_ERROR";
  runId: string;
  message: string;
}
```

### Step Lifecycle

```typescript
interface StepStartedEvent extends EventBase {
  type: "STEP_STARTED";
  runId: string;
  stepName: string;
}

interface StepFinishedEvent extends EventBase {
  type: "STEP_FINISHED";
  runId: string;
  stepName: string;
}
```

### Text Streaming

```typescript
interface TextMessageStartEvent extends EventBase {
  type: "TEXT_MESSAGE_START";
  runId: string;
  messageId: string;
  role: "assistant" | "system" | "user" | "tool";
  stage?: string;
}

interface TextMessageContentEvent extends EventBase {
  type: "TEXT_MESSAGE_CONTENT";
  runId: string;
  messageId: string;
  delta: string; // incremental text chunk
}

interface TextMessageEndEvent extends EventBase {
  type: "TEXT_MESSAGE_END";
  runId: string;
  messageId: string;
  workerAgentOutput: WorkerAgentOutput;
  // stage/model are intentionally excluded from this event
}
```

### Tool Result

```typescript
interface ToolCallResultEvent extends EventBase {
  type: "TOOL_CALL_RESULT";
  messageId: string;
  toolCallId: string;
  toolAgentOutput: ToolAgentOutput; // required
}
```

### Worker/Tool Payloads

```typescript
interface WorkerAgentOutput {
  status: "success" | "partial_success" | "failed";
  answer: string;
  key_points?: string[];
  result_type?: string;
  suggested_actions?: string[];
  error?: {
    code: string;
    message: string;
    retryable?: boolean;
    details?: Record<string, unknown>;
  };
  ui_hints?: Record<string, unknown>;
}

interface ToolAgentOutput {
  tool_name: string;
  tool_call_id: string;
  tool_call_args?: Record<string, unknown>;
  status: "success" | "partial" | "failure";
  result_summary: string;
  ui_hints?: Record<string, unknown>;
  error?: {
    code: string;
    message: string;
    retryable?: boolean;
    details?: Record<string, unknown>;
  };
}
```

---

## History Response Schema

`GET /api/v1/agent/history` returns `STATE_SNAPSHOT` payload.

```typescript
interface AgentHistoryResponse {
  type: "STATE_SNAPSHOT";
  threadId?: string;
  snapshot: {
    scope: "history_day";
    threadId: string | null;
    day: string | null; // YYYY-MM-DD
    hasMore: boolean;
    messages: SnapshotMessage[];
  };
}

interface SnapshotMessage {
  id: string;
  seq: number;
  role: "user" | "assistant" | "system" | "tool";
  content: string;
  metadata?: Record<string, unknown>;
  timestamp: string; // ISO-8601
}

interface AttachmentSignedUrlResponse {
  bucket: string;
  path: string;
  url: string;
}
```

---

## Compatibility Notes

- For `TOOL_CALL_RESULT`, clients should treat `toolAgentOutput` as canonical payload.
- `TEXT_MESSAGE_CONTENT.delta` is defined as incremental text chunk. Implementations should emit multiple chunks for real streaming UX.
- `TEXT_MESSAGE_END` must not include `stage` or `model` in this protocol version.
- History snapshot `messages[]` strictly follows `backend/src/schemas/messages/chat_message.py` `AgentChatMessage` schema.
- Attachment URL rendering is decoupled from history; client should call `/api/v1/agent/attachments/signed-url` using metadata fields.