fetch-elements-of-category

Retrieve BIM elements by category from IFC files, enabling structured querying of building information model data with configurable attribute and relation options.

Instructions

Fetch elements of a specified category

Input Schema

TableJSON Schema

Name	Required	Description	Default
`category`	Yes	Category name. e.g. IFCWALL
`config`	Yes	Configuration for fetching elements

Implementation Reference

main.ts:124-146 (handler)

MCP server tool handler function. Checks if fragments are loaded, calls the core fetchElementsOfCategory helper, and returns the results as JSON text content.

({ category, config }) => {
  if (!fragments) {
    return {
      content: [
        {
          type: 'text',
          text: 'No fragments loaded. Please call load-frag first.',
        },
      ],
    }
  }

  const itemsData = fetchElementsOfCategory(fragments, category, config)

  return {
    content: [
      {
        type: 'text',
        text: JSON.stringify(itemsData),
      },
    ],
  }
}

main.ts:105-123 (schema)

Zod schema for tool inputs: category (string) and config (object with attributesDefault, attributes array, and relations for HasAssociations and IsDefinedBy).

{
  category: z.string().describe('Category name. e.g. IFCWALL'),
  config: z
    .object({
      attributesDefault: z.boolean(),
      attributes: z.array(z.string()),
      relations: z.object({
        HasAssociations: z.object({
          attributes: z.boolean(),
          relations: z.boolean(),
        }),
        IsDefinedBy: z.object({
          attributes: z.boolean(),
          relations: z.boolean(),
        }),
      }),
    })
    .describe('Configuration for fetching elements'),
},

main.ts:102-147 (registration)

Registration of the 'fetch-elements-of-category' tool using server.tool(), including name, description, schema, and handler.

server.tool(
  'fetch-elements-of-category',
  'Fetch elements of a specified category',
  {
    category: z.string().describe('Category name. e.g. IFCWALL'),
    config: z
      .object({
        attributesDefault: z.boolean(),
        attributes: z.array(z.string()),
        relations: z.object({
          HasAssociations: z.object({
            attributes: z.boolean(),
            relations: z.boolean(),
          }),
          IsDefinedBy: z.object({
            attributes: z.boolean(),
            relations: z.boolean(),
          }),
        }),
      })
      .describe('Configuration for fetching elements'),
  },
  ({ category, config }) => {
    if (!fragments) {
      return {
        content: [
          {
            type: 'text',
            text: 'No fragments loaded. Please call load-frag first.',
          },
        ],
      }
    }

    const itemsData = fetchElementsOfCategory(fragments, category, config)

    return {
      content: [
        {
          type: 'text',
          text: JSON.stringify(itemsData),
        },
      ],
    }
  }
)

fragments.ts:50-64 (helper)

Core helper function that implements the logic to fetch elements of a category: gets items matching category regex, filters valid IDs, and retrieves items data with given config.

export const fetchElementsOfCategory = (
  fragments: FRAGS.SingleThreadedFragmentsModel,
  category: string,
  config: Partial<FRAGS.ItemsDataConfig>
) => {
  const elementsOfCategory = fragments.getItemsOfCategories([
    safeRegExp(category),
  ]);
  const ids = Object.values(elementsOfCategory)
    .flat()
    .filter((id) => id !== undefined && id !== null);
  const itemsData = fragments.getItemsData(ids, config);

  return itemsData;
};

Fragment MCP Server