deepseek-harness/website/zh-CN/api/harness/token-meter.md

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# ctx.tokenMeter

`TokenMeterService` — provided by `@deepseek-ai/dsh-token-meter`.

Replay owner for one service-wide estimator and isolated per-session folds.

[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/llm/token-meter/src/index.ts#L106)

### ctx.tokenMeter.contextWindow

```ts website-api
/** Provider context-window capacity used by pressure consumers. */
readonly contextWindow: number
```

Provider context-window capacity used by pressure consumers.

[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/llm/token-meter/src/index.ts#L112)

### ctx.tokenMeter.measure(session, requestHeader?)

```ts website-api
/**
 * Measure current request pressure and surface through the durable tail.
 *
 * Provider usage is reused only when the latest successful call's canonical
 * request envelope matches `requestHeader` and its total is no lower than
 * that call's full heuristic anchor; otherwise the complete envelope and
 * surface are heuristically repriced.
 *
 * `requestHeader` affects request pressure only; surface fields always
 * describe the current session surface. Every call clones those positional
 * nodes, so measurement is O(surface).
 *
 * @param session - session to replay through its current durable tail.
 * @param requestHeader - optional effective request envelope replacing the latest logged header.
 * @returns a detached deeply immutable pressure and surface measurement.
 */
measure(session: Session, requestHeader?: EpochHeader): TokenMeasurement
```

Measure current request pressure and surface through the durable tail.
Provider usage is reused only when the latest successful call's canonical request envelope matches `requestHeader` and its total is no lower than that call's full heuristic anchor; otherwise the complete envelope and surface are heuristically repriced.
`requestHeader` affects request pressure only; surface fields always describe the current session surface. Every call clones those positional nodes, so measurement is O(surface).

- `session` — session to replay through its current durable tail.
- `requestHeader` — optional effective request envelope replacing the latest logged header.

**Returns** a detached deeply immutable pressure and surface measurement.

[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/llm/token-meter/src/index.ts#L143)

### ctx.tokenMeter.estimateMessage(message)

```ts website-api
/**
 * Heuristically price one model-visible message.
 * @param message - message to price without mutation.
 * @returns content and role-framing tokens under the fixed service heuristic.
 */
estimateMessage(message: Message): number
```

Heuristically price one model-visible message.

- `message` — message to price without mutation.

**Returns** content and role-framing tokens under the fixed service heuristic.

[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/llm/token-meter/src/index.ts#L181)