## Upsert Tool

**put** `/v1/tools/`

Create or update a tool

### Body Parameters

- `source_code: string`

  The source code of the function.

- `args_json_schema: optional map[unknown]`

  The args JSON schema of the function.

- `default_requires_approval: optional boolean`

  Whether or not to require approval before executing this tool.

- `description: optional string`

  The description of the tool.

- `enable_parallel_execution: optional boolean`

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

- `json_schema: optional map[unknown]`

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

- `npm_requirements: optional array of NpmRequirement`

  Optional list of npm packages required by this tool.

  - `name: string`

    Name of the npm package.

  - `version: optional string`

    Optional version of the package, following semantic versioning.

- `pip_requirements: optional array of PipRequirement`

  Optional list of pip packages required by this tool.

  - `name: string`

    Name of the pip package.

  - `version: optional string`

    Optional version of the package, following semantic versioning.

- `return_char_limit: optional number`

  The maximum number of characters in the response.

- `source_type: optional string`

  The source type of the function.

- `tags: optional array of string`

  Metadata tags.

### Returns

- `Tool object { id, args_json_schema, created_by_id, 15 more }`

  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: optional map[unknown]`

    The args JSON schema of the function.

  - `created_by_id: optional string`

    The id of the user that made this Tool.

  - `default_requires_approval: optional boolean`

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

  - `description: optional string`

    The description of the tool.

  - `enable_parallel_execution: optional boolean`

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

  - `json_schema: optional map[unknown]`

    The JSON schema of the function.

  - `last_updated_by_id: optional string`

    The id of the user that made this Tool.

  - `metadata_: optional map[unknown]`

    A dictionary of additional metadata for the tool.

  - `name: optional string`

    The name of the function.

  - `npm_requirements: optional array of NpmRequirement`

    Optional list of npm packages required by this tool.

    - `name: string`

      Name of the npm package.

    - `version: optional string`

      Optional version of the package, following semantic versioning.

  - `pip_requirements: optional array of PipRequirement`

    Optional list of pip packages required by this tool.

    - `name: string`

      Name of the pip package.

    - `version: optional string`

      Optional version of the package, following semantic versioning.

  - `project_id: optional string`

    The project id of the tool.

  - `return_char_limit: optional number`

    The maximum number of characters in the response.

  - `source_code: optional string`

    The source code of the function.

  - `source_type: optional string`

    The type of the source code.

  - `tags: optional array of string`

    Metadata tags.

  - `tool_type: optional 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

```http
curl https://api.letta.com/v1/tools/ \
    -X PUT \
    -H 'Content-Type: application/json' \
    -H "Authorization: Bearer $LETTA_API_KEY" \
    -d '{
          "source_code": "source_code"
        }'
```

#### 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"
}
```