add_length_restriction
Define exact, minimum, or maximum character limits for parameters in IDS specifications to enforce data validation rules.
Instructions
Add string length restriction.
Args: spec_id: Specification identifier or name facet_index: Index of facet in location (0-based) parameter_name: Which parameter to restrict (e.g., "value") base_type: XSD base type (e.g., "xs:string") ctx: FastMCP Context (auto-injected) location: "applicability" or "requirements" (default: "requirements") length: Exact length min_length: Minimum length max_length: Maximum length
Returns: {"status": "added", "restriction_type": "length", "spec_id": "S1"}
Example: Add length restriction to attribute value: Tag must be between 5 and 50 characters
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| spec_id | Yes | ||
| facet_index | Yes | ||
| parameter_name | Yes | ||
| base_type | Yes | ||
| location | No | requirements | |
| length | No | ||
| min_length | No | ||
| max_length | No |
Implementation Reference
- The primary handler function implementing the 'add_length_restriction' tool. It adds length restrictions (exact, min, max) to a specified parameter on a facet in an IDS specification using IfcTester's Restriction API.async def add_length_restriction( spec_id: str, facet_index: int, parameter_name: str, base_type: str, ctx: Context, location: str = "requirements", length: Optional[int] = None, min_length: Optional[int] = None, max_length: Optional[int] = None ) -> Dict[str, Any]: """ Add string length restriction. Args: spec_id: Specification identifier or name facet_index: Index of facet in location (0-based) parameter_name: Which parameter to restrict (e.g., "value") base_type: XSD base type (e.g., "xs:string") ctx: FastMCP Context (auto-injected) location: "applicability" or "requirements" (default: "requirements") length: Exact length min_length: Minimum length max_length: Maximum length Returns: {"status": "added", "restriction_type": "length", "spec_id": "S1"} Example: Add length restriction to attribute value: Tag must be between 5 and 50 characters """ try: ids_obj = await get_or_create_session(ctx) spec = _find_specification(ids_obj, spec_id) await ctx.info(f"Adding length restriction to {spec_id}, facet {facet_index}") # Get the facet facet = _get_facet_from_spec(spec, location, facet_index) # Build length parameters length_params = {} if length is not None: length_params["length"] = length if min_length is not None: length_params["minLength"] = min_length if max_length is not None: length_params["maxLength"] = max_length # Create length restriction using IfcTester # Normalize base type (remove 'xs:' prefix if present) normalized_base = _normalize_base_type(base_type) restriction = ids.Restriction( base=normalized_base, options=length_params ) # Apply restriction to the parameter _apply_restriction_to_facet(facet, parameter_name, restriction) await ctx.info(f"Length restriction added: {length_params}") return { "status": "added", "restriction_type": "length", "spec_id": spec_id, "facet_index": facet_index, "parameter": parameter_name, "constraints": length_params } except ToolError: raise except Exception as e: await ctx.error(f"Failed to add length restriction: {str(e)}") raise ToolError(f"Failed to add length restriction: {str(e)}")
- src/ids_mcp_server/server.py:48-48 (registration)Tool registration in the FastMCP server using mcp_server.tool().mcp_server.tool(restrictions.add_length_restriction)
- Helper function that applies the Restriction object to the specified parameter on the facet object.def _apply_restriction_to_facet( facet: Any, parameter_name: str, restriction: ids.Restriction ) -> None: """ Apply restriction to a facet parameter. Args: facet: Facet object (Entity, Property, Attribute, etc.) parameter_name: Parameter to restrict (e.g., "value", "propertySet", "baseName") restriction: Restriction object to apply Raises: ToolError: If parameter doesn't exist on facet """ # Check if parameter exists if not hasattr(facet, parameter_name): raise ToolError( f"Parameter '{parameter_name}' not found on facet type {type(facet).__name__}" ) # Set the restriction on the parameter setattr(facet, parameter_name, restriction)
- Helper function to retrieve a specific facet from the specification based on location ('applicability' or 'requirements') and index.def _get_facet_from_spec( spec: ids.Specification, location: str, facet_index: int ) -> Any: """ Get facet from specification by location and index. Args: spec: Specification object location: "applicability" or "requirements" facet_index: Index of facet in location (0-based) Returns: Facet object Raises: ToolError: If location invalid or index out of range """ if location == "applicability": facets = spec.applicability elif location == "requirements": facets = spec.requirements else: raise ToolError(f"Invalid location: {location}. Must be 'applicability' or 'requirements'") if facet_index < 0 or facet_index >= len(facets): raise ToolError( f"Facet index {facet_index} out of range. " f"Location '{location}' has {len(facets)} facet(s)" ) return facets[facet_index]
- Helper function to normalize the base_type by removing the 'xs:' prefix if present, as required by IfcTester.def _normalize_base_type(base_type: str) -> str: """ Normalize XML Schema base type for IfcTester. IfcTester adds 'xs:' prefix automatically, so we need to remove it if present. Args: base_type: Base type (e.g., "xs:string" or "string") Returns: Normalized base type without 'xs:' prefix (e.g., "string") """ if base_type.startswith("xs:"): return base_type[3:] # Remove 'xs:' prefix return base_type