OpenSearch MCP Server

Instructions

Implementation Reference

• src/opensearch_mcp_server/tools/es_admin/admin_index.py:30-47 (handler)

  The main handler function for the 'get_index_templates' tool. It performs a GET request to '/_index_template' using the OpenSearch client, filters the response, and returns the templates as TextContent objects or an error message.

  @mcp.tool(description="Get index template configurations")
  async def get_index_templates() -> list[TextContent]:
      """
      Get index templates and their configurations.
      Returns template names and their configured number of shards.
      This helps understand how new indices will be created.
      """
      self.logger.info("Fetching index templates...")
      try:
          response = self.es_client.transport.perform_request(
              'GET',
              '/_index_template',
              params={'filter_path': ' _index_template?filter_path=index_templates.name,index_templates.index_template.index_patterns,index_templates.index_template.template.settings.index.number_of_shards'}
          )
          return [TextContent(type="text", text=str(response))]
      except Exception as e:
          self.logger.error(f"Error fetching index templates: {e}")
          return [TextContent(type="text", text=f"Error: {str(e)}")]

• src/opensearch_mcp_server/server.py:40-40 (registration)

  Calls register_tools on the AdminIndexTools instance, which defines and registers the 'get_index_templates' tool via decorators inside its register_tools method.

  admin_index_tools.register_tools(self.mcp)