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

# ChatFunctionTool

Tool definition for function calling (regular function or OpenRouter built-in server tool)

## Supported Types

### ChatFunctionToolFunction

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolChatFunctionToolFunction(components.ChatFunctionToolFunction{/* values here */})
```

### AdvisorServerToolOpenRouter

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolAdvisorServerToolOpenRouter(components.AdvisorServerToolOpenRouter{/* values here */})
```

### BashServerTool

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolBashServerTool(components.BashServerTool{/* values here */})
```

### DatetimeServerTool

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolDatetimeServerTool(components.DatetimeServerTool{/* values here */})
```

### FilesServerTool

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolFilesServerTool(components.FilesServerTool{/* values here */})
```

### FusionServerToolOpenRouter

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolFusionServerToolOpenRouter(components.FusionServerToolOpenRouter{/* values here */})
```

### ImageGenerationServerToolOpenRouter

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolImageGenerationServerToolOpenRouter(components.ImageGenerationServerToolOpenRouter{/* values here */})
```

### ChatSearchModelsServerTool

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolChatSearchModelsServerTool(components.ChatSearchModelsServerTool{/* values here */})
```

### SubagentServerToolOpenRouter

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolSubagentServerToolOpenRouter(components.SubagentServerToolOpenRouter{/* values here */})
```

### WebFetchServerTool

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolWebFetchServerTool(components.WebFetchServerTool{/* values here */})
```

### OpenRouterWebSearchServerTool

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolOpenRouterWebSearchServerTool(components.OpenRouterWebSearchServerTool{/* values here */})
```

### ChatWebSearchShorthand

```go theme={null}
chatFunctionTool := components.CreateChatFunctionToolChatWebSearchShorthand(components.ChatWebSearchShorthand{/* values here */})
```

## Union Discrimination

Use the `Type` field to determine which variant is active, then access the corresponding field:

```go theme={null}
switch chatFunctionTool.Type {
	case components.ChatFunctionToolUnionTypeChatFunctionToolFunction:
		// chatFunctionTool.ChatFunctionToolFunction is populated
	case components.ChatFunctionToolUnionTypeAdvisorServerToolOpenRouter:
		// chatFunctionTool.AdvisorServerToolOpenRouter is populated
	case components.ChatFunctionToolUnionTypeBashServerTool:
		// chatFunctionTool.BashServerTool is populated
	case components.ChatFunctionToolUnionTypeDatetimeServerTool:
		// chatFunctionTool.DatetimeServerTool is populated
	case components.ChatFunctionToolUnionTypeFilesServerTool:
		// chatFunctionTool.FilesServerTool is populated
	case components.ChatFunctionToolUnionTypeFusionServerToolOpenRouter:
		// chatFunctionTool.FusionServerToolOpenRouter is populated
	case components.ChatFunctionToolUnionTypeImageGenerationServerToolOpenRouter:
		// chatFunctionTool.ImageGenerationServerToolOpenRouter is populated
	case components.ChatFunctionToolUnionTypeChatSearchModelsServerTool:
		// chatFunctionTool.ChatSearchModelsServerTool is populated
	case components.ChatFunctionToolUnionTypeSubagentServerToolOpenRouter:
		// chatFunctionTool.SubagentServerToolOpenRouter is populated
	case components.ChatFunctionToolUnionTypeWebFetchServerTool:
		// chatFunctionTool.WebFetchServerTool is populated
	case components.ChatFunctionToolUnionTypeOpenRouterWebSearchServerTool:
		// chatFunctionTool.OpenRouterWebSearchServerTool is populated
	case components.ChatFunctionToolUnionTypeChatWebSearchShorthand:
		// chatFunctionTool.ChatWebSearchShorthand is populated
}
```