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

# Get Custom Function

> Get a custom function by ID, including its source code, input schema, and status

Retrieve a custom function by its ID, including the full source code, auto-extracted input schema, and current status.

## Path Parameters

<ParamField path="function_id" type="string" required>
  Unique identifier of the custom function
</ParamField>

## Response

Returns the full `CustomFunctionItem` object.

## Example Request

```bash theme={"dark"}
curl -X GET -H "x-api-key: <your-api-key>" \
  "https://api.xpander.ai/v1/custom_functions/<function-id>"
```


## OpenAPI

````yaml GET /v1/custom_functions/{function_id}
openapi: 3.1.0
info:
  title: xpander.ai API Service
  description: |2-

        The xpander.ai API Service provides a unified REST API for managing AI agents,
        executing tasks, managing knowledge bases, and integrating with external systems.
        
        Features:
        - Agent Management: Create, update, deploy, and delete AI agents
        - Task Execution: Invoke agents with support for sync, async, and streaming modes
        - Knowledge Bases: Manage knowledge bases and documents for RAG workflows
        - Tools: Discover, connect, and attach tools (connectors, custom functions, MCP servers, sub-agents, workflows) to agents and workflows
        - MCP Integration: Model Context Protocol support for standardized AI interactions
        
        Authentication: All endpoints require authentication via either an API key (`x-api-key`) or an OAuth2 JWT (`Authorization: Bearer <jwt>`).
        
  version: '0.001'
servers:
  - url: https://api.xpander.ai
security: []
paths:
  /v1/custom_functions/{function_id}:
    get:
      tags:
        - API v1
        - Custom Functions
        - Custom Functions CRUD
      summary: Get Custom Function
      description: >-
        Get a custom function by ID, including its source code, input schema,
        and status.
      operationId: Get_custom_function_v1_custom_functions__function_id__get
      parameters:
        - name: function_id
          in: path
          required: true
          schema:
            type: string
            title: Function Id
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CustomFunctionItem'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HTTPValidationError'
      security:
        - APIKeyHeader: []
components:
  schemas:
    CustomFunctionItem:
      properties:
        id:
          type: string
          title: Id
          description: Unique identifier of the custom function.
        name:
          type: string
          title: Name
          description: Human-readable name of the function.
        description:
          anyOf:
            - type: string
            - type: 'null'
          title: Description
          description: Description of what the function does.
        technical_description:
          anyOf:
            - type: string
            - type: 'null'
          title: Technical Description
          description: >-
            Auto-generated technical description from code analysis. Explains
            the function's logic, inputs, and outputs.
        status:
          anyOf:
            - type: string
            - type: 'null'
          title: Status
          description: >-
            Current function status. 'analysing' = being analyzed after
            create/update, 'ready' = available for execution, 'error' = analysis
            failed (check analysis_error_details), 'draft' = not yet analyzed.
        limits:
          anyOf:
            - $ref: '#/components/schemas/CustomFunctionLimitsModel'
            - type: 'null'
          description: Resource limits for execution.
        input_schema:
          anyOf:
            - additionalProperties: true
              type: object
            - type: 'null'
          title: Input Schema
          description: >-
            Auto-detected JSON schema of the function's input parameters.
            Generated during analysis from the function signature and type
            hints.
        source_code:
          anyOf:
            - type: string
            - type: 'null'
          title: Source Code
          description: >-
            Python source code of the function. Only included in get-by-id
            responses, not in list.
        analysis_error_details:
          anyOf:
            - type: string
            - type: 'null'
          title: Analysis Error Details
          description: >-
            Error details if the function analysis failed. Only present when
            status is 'error'.
        organization_id:
          anyOf:
            - type: string
            - type: 'null'
          title: Organization Id
          description: Organization that owns this function.
        created_at:
          anyOf:
            - type: string
            - type: 'null'
          title: Created At
          description: ISO timestamp of when the function was created.
      type: object
      required:
        - id
        - name
      title: CustomFunctionItem
      description: >-
        Public-facing custom function response model.


        Returned by list and get endpoints. Contains function metadata,

        status, auto-detected input schema, and source code.


        To use a custom function as an agent tool:

        1. Add to attached_tools: {"id": "xpander-custom-functions",
        "operation_ids": ["<function_id>"]}

        2. Add to graph: {"item_id": "<function_id>", "name": "<function_name>",
        "type": "tool", "targets": []}
    HTTPValidationError:
      properties:
        detail:
          items:
            $ref: '#/components/schemas/ValidationError'
          type: array
          title: Detail
      type: object
      title: HTTPValidationError
    CustomFunctionLimitsModel:
      properties:
        max_run_time:
          anyOf:
            - type: integer
            - type: 'null'
          title: Max Run Time
          description: >-
            Maximum execution time in seconds. The function will be terminated
            if it exceeds this limit. Default: 15 seconds.
          default: 15
      type: object
      title: CustomFunctionLimitsModel
      description: Resource limits for custom function execution.
    ValidationError:
      properties:
        loc:
          items:
            anyOf:
              - type: string
              - type: integer
          type: array
          title: Location
        msg:
          type: string
          title: Message
        type:
          type: string
          title: Error Type
      type: object
      required:
        - loc
        - msg
        - type
      title: ValidationError
  securitySchemes:
    APIKeyHeader:
      type: apiKey
      description: API Key for authentication
      in: header
      name: x-api-key

````