# Options

URL: https://tailrace.dev/docs/reference/ai-sdk/options

> AiSdkWrapOptions and StreamBlockBehavior for model and tool wrappers.



Shared configuration for [`wrapModel`](/docs/reference/ai-sdk/wrap-model), [`wrapTools`](/docs/reference/ai-sdk/wrap-tools), and [`withAiSdk`](/docs/reference/ai-sdk/with-ai-sdk).

## AiSdkWrapOptions [#aisdkwrapoptions]

```ts
interface AiSdkWrapOptions {
  agent?: string;
  workflowId?: string | (() => string);
  streamBlockBehavior?: StreamBlockBehavior;
  onDecision?: (decisions: Decision[]) => void;
}
```

### `agent` [#agent]

**Type:** `string`\
**Default:** `"default"`

Identity agent id for policy resolution. Matches keys under `identities` in your policy document.

### `workflowId` [#workflowid]

**Type:** `string | (() => string)`\
**Default:** `"default"`

Vault scope for tokenization. The same workflow ID and detected value produce the same token on every check.

Use a chat session ID, thread ID, or per-run UUID. Pass the same value to `restore` at egress.

### `streamBlockBehavior` [#streamblockbehavior]

**Type:** `"abort" | "buffer" | "redact"`\
**Default:** `"abort"`\
**Applies to:** `wrapStream` only (model output streaming)

Controls how a policy **`block`** on model output is translated. Input blocking always throws before the provider runs.

#### `abort` [#abort]

Hold-back scan with a 128-character carry buffer. Safe prefix text is emitted incrementally. On block: cancel the stream and throw `PolicyViolationError`.

**Fail-closed.** Recommended default.

#### `buffer` [#buffer]

Accumulate the entire stream, run one `check` at end, throw on block. No incremental output until the stream completes.

**Fail-closed.** Use for very long single-line secrets (large JWTs, PEM keys) that exceed the carry window.

#### `redact` [#redact]

Hold-back scan. On block, apply **`mask`** (`[ENTITY]` labels) instead of throwing. Stream continues.

**Not fail-closed.** Opt-in only. Audit decisions record `action: "block"` with `appliedAs: "mask"`.

Non-streaming `wrapGenerate` always throws on block regardless of this option.

### `onDecision` [#ondecision]

**Type:** `(decisions: Decision[]) => void`

Called after each successful `check` with audit decisions. Decisions include `entity`, `rule`, `contentHash`, and span offsets - **never raw values**.

Also forwarded to Tailrace audit sinks configured on the instance.

## StreamBlockBehavior [#streamblockbehavior-1]

```ts
type StreamBlockBehavior = "abort" | "buffer" | "redact";
```

## Example [#example]

```ts
tailrace.model(openai("gpt-4o"), {
  agent: "billing-bot",
  workflowId: () => getSessionId(),
  streamBlockBehavior: "abort",
  onDecision: (decisions) => {
    metrics.count("tailrace.decisions", decisions.length);
  },
});
```

## Related [#related]

* [wrapModel](/docs/reference/ai-sdk/wrap-model)
* [Protect PII guide - streaming](/docs/guides/protect-pii-in-ai-sdk#step-5--configure-streaming-optional)