validate

Instructions

Implementation Reference

• src/dataset_viewer/server.py:576-627 (handler)

  Handler for the 'validate' tool in the call_tool method. Validates dataset format with regex and checks existence via GET /is-valid endpoint on datasets-server.huggingface.co, returning JSON result or error messages as TextContent.

  elif name == "validate":
      dataset = arguments["dataset"]
      try:
          # First check format
          if not re.match(r"^[^/]+/[^/]+$", dataset):
              return [
                  types.TextContent(
                      type="text",
                      text="Dataset must be in the format 'owner/dataset'"
                  )
              ]
              
          # Then check if dataset exists and is accessible
          response = await DatasetViewerAPI(auth_token=auth_token).client.get("/is-valid", params={"dataset": dataset})
          response.raise_for_status()
          result = response.json()
          
          return [
              types.TextContent(
                  type="text",
                  text=json.dumps(result, indent=2)
              )
          ]
      except httpx.NetworkError as e:
          return [
              types.TextContent(
                  type="text",
                  text=str(e)
              )
          ]
      except httpx.HTTPStatusError as e:
          if e.response.status_code == 404:
              return [
                  types.TextContent(
                      type="text",
                      text=f"Dataset '{dataset}' not found"
                  )
              ]
          elif e.response.status_code == 403:
              return [
                  types.TextContent(
                      type="text",
                      text=f"Dataset '{dataset}' requires authentication"
                  )
              ]
          else:
              return [
                  types.TextContent(
                      type="text",
                      text=str(e)
                  )
              ]

• src/dataset_viewer/server.py:437-457 (registration)

  Registration of the 'validate' MCP tool in list_tools(), including name, description, and inputSchema defining 'dataset' as required string with pattern and optional auth_token.

  types.Tool(
      name="validate",
      description="Check if a Hugging Face dataset exists and is accessible",
      inputSchema={
          "type": "object",
          "properties": {
              "dataset": {
                  "type": "string", 
                  "description": "Hugging Face dataset identifier in the format owner/dataset",
                  "pattern": "^[^/]+/[^/]+$",
                  "examples": ["ylecun/mnist", "stanfordnlp/imdb"]
              },
              "auth_token": {
                  "type": "string",
                  "description": "Hugging Face auth token for private/gated datasets",
                  "optional": True
              }
          },
          "required": ["dataset"],
      }
  ),

• src/dataset_viewer/server.py:440-456 (schema)

  Input schema for the 'validate' tool, specifying object with required 'dataset' string (pattern ^[^/]+/[^/]+$) and optional 'auth_token'.

  inputSchema={
      "type": "object",
      "properties": {
          "dataset": {
              "type": "string", 
              "description": "Hugging Face dataset identifier in the format owner/dataset",
              "pattern": "^[^/]+/[^/]+$",
              "examples": ["ylecun/mnist", "stanfordnlp/imdb"]
          },
          "auth_token": {
              "type": "string",
              "description": "Hugging Face auth token for private/gated datasets",
              "optional": True
          }
      },
      "required": ["dataset"],
  }

• src/dataset_viewer/server.py:37-56 (helper)

  Helper method 'validate_dataset' in DatasetViewerAPI class that validates dataset format and existence using HEAD /is-valid, raising specific errors. Similar logic to tool handler but raises exceptions instead of returning content.

  async def validate_dataset(self, dataset: str) -> None:
      """Validate dataset ID format and check if it exists"""
      # Validate format (username/dataset-name)
      if not re.match(r"^[^/]+/[^/]+$", dataset):
          raise ValueError("Dataset ID must be in the format 'owner/dataset'")
          
      # Check if dataset exists and is accessible
      try:
          response = await self.client.head(f"/is-valid?dataset={dataset}")
          response.raise_for_status()
      except httpx.NetworkError as e:
          raise ConnectionError(f"Network error while validating dataset: {e}")
      except httpx.HTTPStatusError as e:
          if e.response.status_code == 404:
              raise ValueError(f"Dataset '{dataset}' not found")
          elif e.response.status_code == 403:
              raise ValueError(f"Dataset '{dataset}' exists but requires authentication")
          else:
              raise RuntimeError(f"Error validating dataset: {e}")