> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cascadeflow.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Tools

> Define, format, validate, and execute tools with the TypeScript core package.

## Define a Tool

```typescript theme={null}
import { ToolConfig } from '@cascadeflow/core';

const weatherTool = new ToolConfig({
  name: 'get_weather',
  description: 'Get the current weather for a city',
  parameters: {
    type: 'object',
    properties: {
      city: { type: 'string' },
    },
    required: ['city'],
  },
  function: async ({ city }: { city: string }) => ({ city, temperatureC: 18 }),
});
```

`createTool()` provides an equivalent function-based constructor. The `tool()` helper can infer a schema from examples.

## Execute Tools Automatically

```typescript theme={null}
import { CascadeAgent, ToolExecutor } from '@cascadeflow/core';

const executor = new ToolExecutor([weatherTool]);
const agent = new CascadeAgent({
  models,
  toolExecutor: executor,
});

const result = await agent.run('What is the weather in Zurich?', {
  tools: [weatherTool.toOpenAIFormat()],
  maxSteps: 5,
});
```

## Execute a Parsed Call

```typescript theme={null}
import { ToolCall, ToolCallFormat } from '@cascadeflow/core';

const call = new ToolCall({
  id: 'call_1',
  name: 'get_weather',
  arguments: { city: 'Zurich' },
  providerFormat: ToolCallFormat.OPENAI,
});

const toolResult = await executor.execute(call);
console.log(toolResult.success, toolResult.result);
```

`executeParallel()` runs multiple independent tool calls concurrently.

## Provider Formats

```typescript theme={null}
import {
  toAnthropicFormat,
  toOllamaFormat,
  toOpenAIFormat,
  toProviderFormat,
} from '@cascadeflow/core';
```

The format helpers convert the universal tool definition for provider APIs.

## Validation and Tool Cascading

The core package also exports:

* `ToolValidator` for quality and completeness checks.
* `ToolCallDetector` for detecting tool intent.
* `ToolCascadeRouter` for model and risk-tier selection.
* `ToolCascadeValidator` for validating generated tool calls.
* `ToolCascade` for the combined tool cascade pipeline.

See [Tools and Streaming](/developers/tools-and-streaming) for agent-loop patterns.