Settings

Large language models (LLMs) typically provide settings to augment their output.

All AI SDK functions support the following common settings in addition to the model, the prompt, and additional provider-specific settings:

const result = await generateText({
  model: __MODEL__,
  maxOutputTokens: 512,
  temperature: 0.3,
  maxRetries: 5,
  prompt: 'Invent a new holiday and describe its traditions.',
});

maxOutputTokens

Maximum number of tokens to generate.

temperature

Temperature setting.

The value is passed through to the provider. The range depends on the provider and model. For most providers, 0 means almost deterministic results, and higher values mean more randomness.

It is recommended to set either temperature or topP, but not both.

<Note>In AI SDK 5.0, temperature is no longer set to 0 by default.</Note>

topP

Nucleus sampling.

The value is passed through to the provider. The range depends on the provider and model. For most providers, nucleus sampling is a number between 0 and 1. E.g. 0.1 would mean that only tokens with the top 10% probability mass are considered.

It is recommended to set either temperature or topP, but not both.

topK

Only sample from the top K options for each subsequent token.

Used to remove "long tail" low probability responses. Recommended for advanced use cases only. You usually only need to use temperature.

presencePenalty

The presence penalty affects the likelihood of the model to repeat information that is already in the prompt.

The value is passed through to the provider. The range depends on the provider and model. For most providers, 0 means no penalty.

frequencyPenalty

The frequency penalty affects the likelihood of the model to repeatedly use the same words or phrases.

The value is passed through to the provider. The range depends on the provider and model. For most providers, 0 means no penalty.

stopSequences

The stop sequences to use for stopping the text generation.

If set, the model will stop generating text when one of the stop sequences is generated. Providers may have limits on the number of stop sequences.

seed

It is the seed (integer) to use for random sampling. If set and supported by the model, calls will generate deterministic results.

reasoning

Controls how much reasoning the model performs before generating a response.

If you also set reasoning-related options in providerOptions (e.g. openai.reasoningEffort or anthropic.thinking), the provider-specific options take precedence and the top-level reasoning parameter is ignored.

See the reasoning guide for details on per-provider mapping and migration from providerOptions.

maxRetries

Maximum number of retries. Set to 0 to disable retries. Default: 2.

abortSignal

An optional abort signal that can be used to cancel the call.

The abort signal can e.g. be forwarded from a user interface to cancel the call, or to define a timeout using AbortSignal.timeout.

Example: AbortSignal.timeout

const result = await generateText({
  model: __MODEL__,
  prompt: 'Invent a new holiday and describe its traditions.',
  abortSignal: AbortSignal.timeout(5000), // 5 seconds
});

timeout

An optional timeout in milliseconds. The call will be aborted if it takes longer than the specified duration.

This is a convenience parameter that creates an abort signal internally. It can be used alongside abortSignal - if both are provided, the call will abort when either condition is met.

You can specify the timeout either as a number (milliseconds) or as an object with totalMs, stepMs, and/or chunkMs properties:

• totalMs: The total timeout for the entire call including all steps.
• stepMs: The timeout for each individual step (LLM call). This is useful for multi-step generations where you want to limit the time spent on each step independently.
• chunkMs: The timeout between stream chunks (streaming only). The call will abort if no new chunk is received within this duration. This is useful for detecting stalled streams.

Example: 5 second timeout (number format)

const result = await generateText({
  model: __MODEL__,
  prompt: 'Invent a new holiday and describe its traditions.',
  timeout: 5000, // 5 seconds
});

Example: 5 second total timeout (object format)

const result = await generateText({
  model: __MODEL__,
  prompt: 'Invent a new holiday and describe its traditions.',
  timeout: { totalMs: 5000 }, // 5 seconds
});

Example: 10 second step timeout

const result = await generateText({
  model: __MODEL__,
  prompt: 'Invent a new holiday and describe its traditions.',
  timeout: { stepMs: 10000 }, // 10 seconds per step
});

Example: Combined total and step timeout

const result = await generateText({
  model: __MODEL__,
  prompt: 'Invent a new holiday and describe its traditions.',
  timeout: {
    totalMs: 60000, // 60 seconds total
    stepMs: 10000, // 10 seconds per step
  },
});

Example: Per-chunk timeout for streaming (streamText only)

const result = streamText({
  model: __MODEL__,
  prompt: 'Invent a new holiday and describe its traditions.',
  timeout: { chunkMs: 5000 }, // abort if no chunk received for 5 seconds
});

headers

Additional HTTP headers to be sent with the request. Only applicable for HTTP-based providers.

You can use the request headers to provide additional information to the provider, depending on what the provider supports. For example, some observability providers support headers such as Prompt-Id.

import { generateText } from 'ai';
__PROVIDER_IMPORT__;

const result = await generateText({
  model: __MODEL__,
  prompt: 'Invent a new holiday and describe its traditions.',
  headers: {
    'Prompt-Id': 'my-prompt-id',
  },
});