Function llmToolSelectorMiddleware

llmToolSelectorMiddleware(options: InferInteropZodInput): AgentMiddleware<any>
Middleware for selecting tools using an LLM-based strategy.

When an agent has many tools available, this middleware filters them down to only the most relevant ones for the user's query. This reduces token usage and helps the main model focus on the right tools.
Parameters
- options: InferInteropZodInput
  Configuration options for the middleware
  - model
    The language model to use for tool selection (default: the provided model from the agent options).
  - systemPrompt
    Instructions for the selection model.
  - maxTools
    Maximum number of tools to select. If the model selects more, only the first maxTools will be used. No limit if not specified.
  - alwaysInclude
    Tool names to always include regardless of selection. These do not count against the maxTools limit.
Returns AgentMiddleware<any>
Example
Limit to 3 tools:
```
import { llmToolSelectorMiddleware } from "langchain/agents/middleware";

const middleware = llmToolSelectorMiddleware({ maxTools: 3 });

const agent = createAgent({
  model: "openai:gpt-4o",
  tools: [tool1, tool2, tool3, tool4, tool5],
  middleware: [middleware],
});
```
Example
Use a smaller model for selection:
```
const middleware = llmToolSelectorMiddleware({
  model: "openai:gpt-4o-mini",
  maxTools: 2
});
```
- Defined in libs/langchain/src/agents/middleware/llmToolSelector.ts:119