openrouter_chat: Send LLM Messages to the OpenRouter Chat API

Description

Sends a message history to the OpenRouter API, which provides access to hundreds of models from different providers through a single OpenAI-compatible endpoint.

Usage

openrouter_chat(
  .llm,
  .model = "anthropic/claude-sonnet-5",
  .max_tokens = 2048,
  .temperature = NULL,
  .top_p = NULL,
  .frequency_penalty = NULL,
  .presence_penalty = NULL,
  .stop = NULL,
  .stream = FALSE,
  .json_schema = NULL,
  .tools = NULL,
  .tool_choice = NULL,
  .reasoning = NULL,
  .provider = NULL,
  .route = NULL,
  .models = NULL,
  .api_url = "https://openrouter.ai",
  .timeout = 60,
  .verbose = FALSE,
  .dry_run = FALSE,
  .max_tries = 3,
  .max_tool_rounds = 10
)

Value

A new LLMMessage object containing the original messages plus the assistant's response.

Arguments

.llm

An LLMMessage object containing the conversation history.

.model

The model identifier to use (default: "google/gemini-3.6-flash"). Any model available on OpenRouter can be used.

.max_tokens

Maximum number of tokens in the response (default: 2048).

.temperature

Controls randomness (0–2, optional).

.top_p

Nucleus sampling parameter (0–1, optional).

.frequency_penalty

Penalizes repeated tokens (-2 to 2, optional).

.presence_penalty

Encourages new topics (-2 to 2, optional).

.stop

One or more stop sequences (optional).

.stream

Logical; if TRUE, streams the response (default: FALSE).

.json_schema

A JSON schema object for structured output (default: NULL).

.tools

Either a single TOOL object or a list of TOOL objects for tool calls.

.tool_choice

Tool-calling behavior: "none", "auto", or "required" (optional).

.reasoning

A named list controlling reasoning token behavior (optional). Supported fields vary by model family:

effort: one of "xhigh", "high", "medium", "low", "minimal", "none" (OpenAI/Grok)
max_tokens: integer specifying the reasoning token budget (Anthropic/Gemini/Alibaba)
exclude: logical; if TRUE, reasoning is used internally but not returned in the response
enabled: logical; if TRUE, activates reasoning at default settings

Example: list(effort = "high") or list(max_tokens = 4000, exclude = FALSE).

.provider

A named list of OpenRouter provider preferences, e.g. list(order = c("Anthropic", "AWS Bedrock"), allow_fallbacks = TRUE) (optional).

.route

OpenRouter routing strategy; "fallback" routes to the next model if the primary is unavailable (optional).

.models

A character vector of model IDs to use as fallbacks when the primary model is unavailable (optional). Used together with .route = "fallback".

.api_url

Base URL for the OpenRouter API (default: "https://openrouter.ai").

.timeout

Request timeout in seconds (default: 60).

.verbose

If TRUE, displays additional information after the API call (default: FALSE).

.dry_run

If TRUE, returns the request object without executing it (default: FALSE).

.max_tries

Maximum retries (default: 3).

.max_tool_rounds

Maximum number of tool use iterations (default: 10).