## Create Tool

`client.tools.create(ToolCreateParamsbody, RequestOptionsoptions?): Tool`

**post** `/v1/tools/`

Create a new tool

### Parameters

- `body: ToolCreateParams`

  - `source_code: string`

    The source code of the function.

  - `args_json_schema?: Record<string, unknown> | null`

    The args JSON schema of the function.

  - `default_requires_approval?: boolean | null`

    Whether or not to require approval before executing this tool.

  - `description?: string | null`

    The description of the tool.

  - `enable_parallel_execution?: boolean | null`

    If set to True, then this tool will potentially be executed concurrently with other tools. Default False.

  - `json_schema?: Record<string, unknown> | null`

    The JSON schema of the function (auto-generated from source_code if not provided)

  - `npm_requirements?: Array<NpmRequirement> | null`

    Optional list of npm packages required by this tool.

    - `name: string`

      Name of the npm package.

    - `version?: string | null`

      Optional version of the package, following semantic versioning.

  - `pip_requirements?: Array<PipRequirement> | null`

    Optional list of pip packages required by this tool.

    - `name: string`

      Name of the pip package.

    - `version?: string | null`

      Optional version of the package, following semantic versioning.

  - `return_char_limit?: number`

    The maximum number of characters in the response.

  - `source_type?: string`

    The source type of the function.

  - `tags?: Array<string> | null`

    Metadata tags.

### Returns

- `Tool`

  Representation of a tool, which is a function that can be called by the agent.

  - `id: string`

    The human-friendly ID of the Tool

  - `args_json_schema?: Record<string, unknown> | null`

    The args JSON schema of the function.

  - `created_by_id?: string | null`

    The id of the user that made this Tool.

  - `default_requires_approval?: boolean | null`

    Default value for whether or not executing this tool requires approval.

  - `description?: string | null`

    The description of the tool.

  - `enable_parallel_execution?: boolean | null`

    If set to True, then this tool will potentially be executed concurrently with other tools. Default False.

  - `json_schema?: Record<string, unknown> | null`

    The JSON schema of the function.

  - `last_updated_by_id?: string | null`

    The id of the user that made this Tool.

  - `metadata_?: Record<string, unknown> | null`

    A dictionary of additional metadata for the tool.

  - `name?: string | null`

    The name of the function.

  - `npm_requirements?: Array<NpmRequirement> | null`

    Optional list of npm packages required by this tool.

    - `name: string`

      Name of the npm package.

    - `version?: string | null`

      Optional version of the package, following semantic versioning.

  - `pip_requirements?: Array<PipRequirement> | null`

    Optional list of pip packages required by this tool.

    - `name: string`

      Name of the pip package.

    - `version?: string | null`

      Optional version of the package, following semantic versioning.

  - `project_id?: string | null`

    The project id of the tool.

  - `return_char_limit?: number`

    The maximum number of characters in the response.

  - `source_code?: string | null`

    The source code of the function.

  - `source_type?: string | null`

    The type of the source code.

  - `tags?: Array<string>`

    Metadata tags.

  - `tool_type?: ToolType`

    The type of the tool.

    - `"custom"`

    - `"letta_core"`

    - `"letta_memory_core"`

    - `"letta_multi_agent_core"`

    - `"letta_sleeptime_core"`

    - `"letta_voice_sleeptime_core"`

    - `"letta_builtin"`

    - `"letta_files_core"`

    - `"external_langchain"`

    - `"external_composio"`

    - `"external_mcp"`

### Example

```typescript
import Letta from '@letta-ai/letta-client';

const client = new Letta({
  apiKey: process.env['LETTA_API_KEY'], // This is the default and can be omitted
});

const tool = await client.tools.create({ source_code: 'source_code' });

console.log(tool.id);
```

#### Response

```json
{
  "id": "tool-123e4567-e89b-12d3-a456-426614174000",
  "args_json_schema": {
    "foo": "bar"
  },
  "created_by_id": "created_by_id",
  "default_requires_approval": true,
  "description": "description",
  "enable_parallel_execution": true,
  "json_schema": {
    "foo": "bar"
  },
  "last_updated_by_id": "last_updated_by_id",
  "metadata_": {
    "foo": "bar"
  },
  "name": "name",
  "npm_requirements": [
    {
      "name": "x",
      "version": "version"
    }
  ],
  "pip_requirements": [
    {
      "name": "x",
      "version": "version"
    }
  ],
  "project_id": "project_id",
  "return_char_limit": 1,
  "source_code": "source_code",
  "source_type": "source_type",
  "tags": [
    "string"
  ],
  "tool_type": "custom"
}
```