# Agent SSE Events

本文档描述 `GET /api/v1/agent/runs/{thread_id}/events` 的事件协议。

---

## 1) 事件管道

后端事件流转如下：

1. Runtime 直接产出 AG-UI 事件（如 `RUN_STARTED`、`TOOL_CALL_RESULT`）
2. `agui_codec` 仅做协议对齐与字段净化（例如移除仅后端内部统计字段）
3. 事件同时：
   - 持久化到数据库（用于 history）
   - 发布到 Redis Stream（用于 SSE）
4. `/runs/{thread_id}/events` 从 Redis Stream 读取并输出 SSE

---

## 2) SSE 帧格式

每条事件遵循标准 SSE：

```text
id: <redis-stream-id>
event: <AG-UI-EVENT-TYPE>
data: <json>

```

- `id` 可用于断点续流（`Last-Event-ID`）
- `event` 与 JSON 内 `type` 一致（例如 `RUN_STARTED`）
- 空闲时可能出现 keep-alive 注释帧：

```text
: keep-alive

```

---

## 3) 事件类型（当前实现）

### 3.1 Run 生命周期

#### `RUN_STARTED`

```json
{
  "type": "RUN_STARTED",
  "threadId": "...",
  "runId": "..."
}
```

#### `RUN_FINISHED`

```json
{
  "type": "RUN_FINISHED",
  "threadId": "...",
  "runId": "..."
}
```

#### `RUN_ERROR`

```json
{
  "type": "RUN_ERROR",
  "threadId": "...",
  "runId": "...",
  "message": "runtime execution failed",
  "code": null
}
```

### 3.2 阶段事件

#### `STEP_STARTED`

```json
{
  "type": "STEP_STARTED",
  "threadId": "...",
  "runId": "...",
  "stepName": "router" | "worker"
}
```

#### `STEP_FINISHED`

```json
{
  "type": "STEP_FINISHED",
  "threadId": "...",
  "runId": "...",
  "stepName": "router" | "worker"
}
```

### 3.3 Tool 事件

#### `TOOL_CALL_START`

```json
{
  "type": "TOOL_CALL_START",
  "threadId": "...",
  "runId": "...",
  "messageId": "...",
  "toolCallId": "...",
  "toolCallName": "...",
  "stage": "worker"
}
```

#### `TOOL_CALL_ARGS`

```json
{
  "type": "TOOL_CALL_ARGS",
  "threadId": "...",
  "runId": "...",
  "messageId": "...",
  "toolCallId": "...",
  "toolCallName": "...",
  "args": {},
  "stage": "worker"
}
```

#### `TOOL_CALL_END`

```json
{
  "type": "TOOL_CALL_END",
  "threadId": "...",
  "runId": "...",
  "messageId": "...",
  "toolCallId": "...",
  "toolCallName": "...",
  "stage": "worker"
}
```

#### `TOOL_CALL_RESULT`

```json
{
  "type": "TOOL_CALL_RESULT",
  "threadId": "...",
  "runId": "...",
  "messageId": "...",
  "role": "tool",
  "stage": "worker",
  "tool_name": "...",
  "tool_call_id": "...",
  "tool_call_args": {},
  "status": "success" | "failed",
  "result_summary": "...",
  "ui_schema": {},
  "error": null
}
```

### 3.4 文本完成事件

#### `TEXT_MESSAGE_END`

当前实现仅在 worker 输出完成后发送完整结果，不发送 token delta 事件。

```json
{
  "type": "TEXT_MESSAGE_END",
  "threadId": "...",
  "runId": "...",
  "messageId": "...",
  "role": "assistant",
  "stage": "worker",
  "status": "success" | "partial_success" | "failed",
  "answer": "...",
  "key_points": [],
  "result_type": "execution_report" | "clarification" | "error_report" | "unknown",
  "suggested_actions": [],
  "error": null,
  "ui_schema": {}
}
```

`inputTokens`、`outputTokens`、`cost`、`latencyMs`、`model` 属于后端内部统计字段，不在 SSE 对外协议中暴露。

### 3.5 快照事件

编码器支持以下 AG-UI 类型映射：

- `STATE_SNAPSHOT`
- `MESSAGES_SNAPSHOT`

当前 `/runs/{thread_id}/events` 主流程通常不主动产出这两类事件；历史查询请使用 `/history`。

---

## 4) 字段命名约定

- 事件顶层通用字段使用 AG-UI 风格：`type`、`threadId`、`runId`
- 部分业务字段沿运行时模型历史命名保留下划线：
  - `tool_name`
  - `tool_call_id`
  - `tool_call_args`
  - `ui_schema`

这部分命名属于当前后端实现约束，文档与实现保持一致。