# 会话标题

[English](session-title.md) | 中文

[`@deepseek-ai/dsh-session-title`](../../packages/session-title/session-title) 所拥有的持久化后写覆盖标题状态与可选异步提供方词汇。共享 LLM（大语言模型）辅助组件负责精确的辅助请求记录。各包（package）README 负责时序、回退、失败与 fork 行为；生成的[持久化日志事件目录](../persistence-catalog.md)负责完整的事件声明。

源码：[`packages/session-title/session-title/src/index.ts`](../../packages/session-title/session-title/src/index.ts)、[`packages/session-title/session-title-llm/src/index.ts`](../../packages/session-title/session-title-llm/src/index.ts)

## 持久标题状态

提供方生成修订时会记录 `SessionTitleProviderId`。`SessionTitleEventData` 携带精确的人类消息来源信息，`SessionTitleSnapshot` 则加入 `foldSessionTitle()` 选出的持久事件信封事实。

```ts type-equiv
/** Identifies one session-title provider registration. */
type SessionTitleProviderId = Branded<'SessionTitleProviderId'>
```

```ts type-equiv
/** Exact auxiliary model route that produced a title. */
interface SessionTitleModelProvenance {
  /** Registered LLM provider route. */
  readonly provider: string
  /** Provider model id. */
  readonly model: string
}
```

```ts type-equiv
/** Durable ownership record for an accepted session title. */
type SessionTitleSource =
  | { readonly kind: 'fallback' }
  | {
    readonly kind: 'provider'
    readonly provider: SessionTitleProviderId
    readonly model?: SessionTitleModelProvenance
  }
```

```ts type-equiv
/** Payload of the log-only `session/title` event. */
interface SessionTitleEventData {
  /** Normalized non-empty title text. */
  readonly title: string
  /** Exact human `user/message` seqs used to derive this title. */
  readonly messageSeqs: number[]
  /** Built-in fallback or registered-provider provenance. */
  readonly source: SessionTitleSource
}
```

```ts type-equiv
/** Latest folded title plus the title event's durable envelope facts. */
interface SessionTitleSnapshot extends SessionTitleEventData {
  /** Seq of the latest `session/title` event. */
  readonly eventSeq: number
  /** Timestamp of the latest `session/title` event. */
  readonly updatedAt: number
}
```

## 辅助请求记录

共享 LLM 辅助组件会在调用模型前，记录每一项已经过验证且可分发的标题请求。即使后续生成失败，载荷仍会复现模型可见的系统输入与消息输入、路由、输出上限、提供方归属和源消息归因。

```ts type-equiv
/** Exact model-visible request recorded before one auxiliary title dispatch. */
interface SessionTitleLlmRequestEventData {
  /** Registered title-provider identity responsible for the request. */
  readonly titleProvider: SessionTitleProviderId
  /** Exact human `user/message` seqs represented in `messages`. */
  readonly messageSeqs: number[]
  /** Exact auxiliary LLM route. */
  readonly route: SessionTitleModelProvenance
  /** Exact auxiliary system prompt. */
  readonly system: string
  /** Exact auxiliary message list. */
  readonly messages: Message[]
  /** Exact auxiliary output-token cap. */
  readonly maxTokens: number
}
```

## 提供方输入与输出

服务会对截至某一修订的合格消息创建快照。提供方返回的 seq 仅可来自该请求；由服务负责的接受过程会验证顺序、规范化标题、强制执行字节上限并追加来源信息。

```ts type-equiv
/** One eligible human text message exposed to title providers. */
interface SessionTitleUserMessage {
  /** Source `user/message` event seq. */
  readonly seq: number
  /** Exact concatenated text-block content. */
  readonly text: string
}
```

```ts type-equiv
/** Automatic generation cadence owned by a registered provider. */
type SessionTitleAutomaticMode = 'first-message' | 'all-user-messages'
```

```ts type-equiv
/** Immutable input supplied to one title-provider call. */
interface SessionTitleProviderRequest {
  /** Live session being titled. */
  readonly session: Session
  /** All eligible human messages through this generation revision. */
  readonly messages: readonly SessionTitleUserMessage[]
  /** Exact current logged main-request route, when one has been recorded. */
  readonly route?: SessionTitleModelProvenance
  /** Cancellation for supersession, disposal, timeout composition, or the explicit caller. */
  readonly signal: AbortSignal
}
```

```ts type-equiv
/** Provider output before service-owned normalization and durable acceptance. */
interface SessionTitleProviderResult {
  /** Proposed title text. */
  readonly title: string
  /** Exact seqs from `request.messages` used by this result. */
  readonly messageSeqs: readonly number[]
  /** Auxiliary LLM route, when generation used a model. */
  readonly model?: SessionTitleModelProvenance
}
```

```ts type-equiv
/** One optional asynchronous title implementation registered with the service. */
interface SessionTitleProvider {
  /** Stable provider identity recorded in title provenance. */
  readonly id: SessionTitleProviderId
  /** When new human prompts start automatic generation. */
  readonly automatic: SessionTitleAutomaticMode
  /**
   * Produce one title revision.
   * @param request - message snapshot, current route, session, and cancellation.
   * @returns proposed title plus exact input seqs and optional model provenance.
   */
  generate(request: SessionTitleProviderRequest): Promise<SessionTitleProviderResult>
}
```
