STAC MCP Server

Instructions

Implementation Reference

• stac_mcp/tools/get_collection.py:12-55 (handler)

  The core handler function that executes the 'get_collection' tool: fetches the STAC collection by ID using STACClient and formats a textual or JSON response.

  def handle_get_collection(
      client: STACClient,
      arguments: dict[str, Any],
  ) -> list[TextContent] | dict[str, Any]:
      collection_id = arguments["collection_id"]
      collection = client.get_collection(collection_id)
      if collection is None:
          return {"type": "collection", "collection": None}
      if arguments.get("output_format") == "json":
          return {"type": "collection", "collection": collection}
      title = collection.get("title", collection.get("id", collection_id))
      result_text = f"**Collection: {title}**\n\n"
      identifier = collection.get("id", collection_id)
      result_text += f"ID: `{identifier}`\n"
      description = collection.get("description", "No description available")
      result_text += f"Description: {description}\n"
      license_value = collection.get("license", "unspecified")
      result_text += f"License: {license_value}\n\n"
      extent = collection.get("extent") or {}
      if extent:
          spatial = extent.get("spatial") or {}
          bbox_list = spatial.get("bbox") or []
          if bbox_list:
              bbox = bbox_list[0]
              if isinstance(bbox, list | tuple) and len(bbox) >= BBOX_MIN_COORDS:
                  result_text += (
                      "Spatial Extent: "
                      f"[{bbox[0]:.2f}, {bbox[1]:.2f}, {bbox[2]:.2f}, {bbox[3]:.2f}]\n"
                  )
          temporal = extent.get("temporal") or {}
          interval_list = temporal.get("interval") or []
          if interval_list:
              interval = interval_list[0]
              start = interval[0] if len(interval) > 0 else "unknown"
              end = interval[1] if len(interval) > 1 else "present"
              result_text += f"Temporal Extent: {start} to {end or 'present'}\n"
      providers = collection.get("providers") or []
      if providers:
          result_text += f"\nProviders: {len(providers)}\n"
          for provider in providers:
              name = provider.get("name", "Unknown")
              roles = provider.get("roles", [])
              result_text += f"  - {name} ({roles})\n"
      return [TextContent(type="text", text=result_text)]

• stac_mcp/tools/execution.py:56-67 (registration)

  Internal registry in execution.py that maps the tool name 'get_collection' to its handler function handle_get_collection.

  _TOOL_HANDLERS: dict[str, Handler] = {
      "search_collections": handle_search_collections,
      "get_collection": handle_get_collection,
      "search_items": handle_search_items,
      "get_item": handle_get_item,
      "estimate_data_size": handle_estimate_data_size,
      "get_root": handle_get_root,
      "get_conformance": handle_get_conformance,
      "get_queryables": handle_get_queryables,
      "get_aggregations": handle_get_aggregations,
      "sensor_registry_info": handle_sensor_registry_info,
  }

• stac_mcp/server.py:50-60 (registration)

  FastMCP server registration of the 'get_collection' tool, defining input schema via parameters (collection_id: str, catalog_url: str | None) and delegating to execution.execute_tool.

  @app.tool
  async def get_collection(
      collection_id: str, catalog_url: str | None = None
  ) -> list[dict[str, Any]]:
      """Fetch a single STAC Collection by id."""
      return await execution.execute_tool(
          "get_collection",
          arguments={"collection_id": collection_id},
          catalog_url=catalog_url,
          headers=None,
      )

• stac_mcp/server.py:51-60 (schema)

  Input schema for the tool derived from the registered function signature: requires collection_id (str), optional catalog_url (str). Output is list[dict[str, Any]]. Note: handler supports additional 'output_format' param.

  async def get_collection(
      collection_id: str, catalog_url: str | None = None
  ) -> list[dict[str, Any]]:
      """Fetch a single STAC Collection by id."""
      return await execution.execute_tool(
          "get_collection",
          arguments={"collection_id": collection_id},
          catalog_url=catalog_url,
          headers=None,
      )