> ## Documentation Index
> Fetch the complete documentation index at: https://opentouter.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# ChatRequest - TypeScript SDK
> ChatRequest type definition
The TypeScript SDK and docs are currently in beta.
Report issues on [GitHub](https://github.com/OpenRouterTeam/typescript-sdk/issues).
Chat completion request parameters
## Example Usage
```typescript lines theme={null}
import { ChatRequest } from "@openrouter/sdk/models";
let value: ChatRequest = {
messages: [
{
content: "You are a helpful assistant.",
role: "system",
},
{
content: "What is the capital of France?",
role: "user",
},
],
};
```
## Fields
| Field | Type | Required | Description | Example |
| --------------------- | ------------------------------------------------------------------------------------------------------------------ | -------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------ |
| `cacheControl` | [models.AnthropicCacheControlDirective](/agent-sdk/typescript/api-reference/models/anthropiccachecontroldirective) | :heavy\_minus\_sign: | Enable automatic prompt caching. When set at the top level, the system automatically applies cache breakpoints to the last cacheable block in the request. Currently supported for Anthropic Claude models. | `{"type": "ephemeral"}` |
| `debug` | [models.ChatDebugOptions](/agent-sdk/typescript/api-reference/models/chatdebugoptions) | :heavy\_minus\_sign: | Debug options for inspecting request transformations (streaming only) | `{"echo_upstream_body": true}` |
| `frequencyPenalty` | *number* | :heavy\_minus\_sign: | Frequency penalty (-2.0 to 2.0) | 0 |
| `imageConfig` | `Record` | :heavy\_minus\_sign: | Provider-specific image configuration options. Keys and values vary by model/provider. See [https://openrouter.ai/docs/guides/overview/multimodal/image-generation](https://openrouter.ai/docs/guides/overview/multimodal/image-generation) for more details. | `{"aspect_ratio": "16:9","quality": "high"}` |
| `logitBias` | `Record` | :heavy\_minus\_sign: | Token logit bias adjustments | `{"50256": -100}` |
| `logprobs` | *boolean* | :heavy\_minus\_sign: | Return log probabilities | false |
| `maxCompletionTokens` | *number* | :heavy\_minus\_sign: | Maximum tokens in completion | 100 |
| `maxTokens` | *number* | :heavy\_minus\_sign: | Maximum tokens (deprecated, use max\_completion\_tokens). Note: some providers enforce a minimum of 16. | 100 |
| `messages` | *models.ChatMessages*\[] | :heavy\_check\_mark: | List of messages for the conversation | \[
`{"content": "Hello!","role": "user"}`
] |
| `metadata` | `Record` | :heavy\_minus\_sign: | Key-value pairs for additional object information (max 16 pairs, 64 char keys, 512 char values) | `{"session_id": "session-456","user_id": "user-123"}` |
| `modalities` | [models.Modality](/agent-sdk/typescript/api-reference/models/modality)\[] | :heavy\_minus\_sign: | Output modalities for the response. Supported values are "text", "image", and "audio". | \[
"text",
"image"
] |
| `model` | *string* | :heavy\_minus\_sign: | Model to use for completion | openai/gpt-4 |
| `models` | *string*\[] | :heavy\_minus\_sign: | Models to use for completion | \[
"openai/gpt-4",
"openai/gpt-4o"
] |
| `parallelToolCalls` | *boolean* | :heavy\_minus\_sign: | Whether to enable parallel function calling during tool use. When true, the model may generate multiple tool calls in a single response. | true |
| `plugins` | *models.ChatRequestPlugin*\[] | :heavy\_minus\_sign: | Plugins you want to enable for this request, including their settings. | |
| `presencePenalty` | *number* | :heavy\_minus\_sign: | Presence penalty (-2.0 to 2.0) | 0 |
| `provider` | [models.ProviderPreferences](/agent-sdk/typescript/api-reference/models/providerpreferences) | :heavy\_minus\_sign: | When multiple model providers are available, optionally indicate your routing preference. | `{"allow_fallbacks": true}` |
| `reasoning` | [models.ChatRequestReasoning](/agent-sdk/typescript/api-reference/models/chatrequestreasoning) | :heavy\_minus\_sign: | Configuration options for reasoning models | `{"effort": "medium","summary": "concise"}` |
| `responseFormat` | *models.ResponseFormat* | :heavy\_minus\_sign: | Response format configuration | `{"type": "json_object"}` |
| `seed` | *number* | :heavy\_minus\_sign: | Random seed for deterministic outputs | 42 |
| `serviceTier` | [models.ChatRequestServiceTier](/agent-sdk/typescript/api-reference/models/chatrequestservicetier) | :heavy\_minus\_sign: | The service tier to use for processing this request. | auto |
| `sessionId` | *string* | :heavy\_minus\_sign: | A unique identifier for grouping related requests (e.g., a conversation or agent workflow). When provided, OpenRouter uses it as the sticky routing key, routing all requests in the session to the same provider to maximize prompt cache hits. Also used for observability grouping. If provided in both the request body and the x-session-id header, the body value takes precedence. Maximum of 256 characters. | |
| `stop` | *models.Stop* | :heavy\_minus\_sign: | Stop sequences (up to 4) | \[
""
] |
| `stopServerToolsWhen` | *models.StopServerToolsWhenCondition*\[] | :heavy\_minus\_sign: | Stop conditions for the server-tool agent loop. Any condition firing halts the loop (OR logic). When set, this overrides `max_tool_calls`. | \[
`{"step_count": 5,"type": "step_count_is"}`,
`{"max_cost_in_dollars": 0.5,"type": "max_cost"}`
] |
| `stream` | *boolean* | :heavy\_minus\_sign: | Enable streaming response | false |
| `streamOptions` | [models.ChatStreamOptions](/agent-sdk/typescript/api-reference/models/chatstreamoptions) | :heavy\_minus\_sign: | Streaming configuration options | `{"include_usage": true}` |
| `temperature` | *number* | :heavy\_minus\_sign: | Sampling temperature (0-2) | 0.7 |
| `toolChoice` | *models.ChatToolChoice* | :heavy\_minus\_sign: | Tool choice configuration | auto |
| `tools` | *models.ChatFunctionTool*\[] | :heavy\_minus\_sign: | Available tools for function calling | \[
`{"function": {"description": "Get weather","name": "get_weather"}`,
"type": "function"
}
] |
| `topLogprobs` | *number* | :heavy\_minus\_sign: | Number of top log probabilities to return (0-20) | 5 |
| `topP` | *number* | :heavy\_minus\_sign: | Nucleus sampling parameter (0-1) | 1 |
| `trace` | [models.TraceConfig](/agent-sdk/typescript/api-reference/models/traceconfig) | :heavy\_minus\_sign: | Metadata for observability and tracing. Known keys (trace\_id, trace\_name, span\_name, generation\_name, parent\_span\_id) have special handling. Additional keys are passed through as custom metadata to configured broadcast destinations. | `{"trace_id": "trace-abc123","trace_name": "my-app-trace"}` |
| `user` | *string* | :heavy\_minus\_sign: | Unique user identifier | user-123 |