Custom Context MCP Server

Instructions

Implementation Reference

• src/common/tools.ts:55-86 (handler)

  The core handler function that processes the template and text inputs, extracts key-value pairs using helper functions, constructs a prompt with the JSON result, and returns it as MCP content.

  const textToJsonTool = (template: string, text: string) => {
  	if (!template || !text) {
  		throw new Error("Both template and text are required");
  	}
  
  	try {
  		const templateObj = JSON.parse(template);
  		const templateKeys = deepObjectKeys(templateObj, true);
  
  		const jsonResult = extractKeyValuesFromText(text, templateKeys);
  
  		const resultPrompt = `
  		Print this JSON result in JSON format.
  
  		JSON result:
  		${JSON.stringify(jsonResult)}
  
  		`;
  
  		return {
  			content: [
  				{
  					type: "text",
  					text: resultPrompt,
  				},
  			],
  		};
  	} catch (error) {
  		logger.error("Error processing template:", error);
  		throw new Error(`Failed to process template: ${error}`);
  	}
  };

• src/common/types.ts:6-9 (schema)

  Zod schema defining the input parameters for the text-to-json tool: template (JSON template string) and text (grouped text string).

  const TextToJsonSchema = z.object({
  	template: z.string().describe("JSON template with placeholders"),
  	text: z.string().describe("Groupped text from groupTextByJson tool"),
  });

• src/index.ts:45-49 (registration)

  Tool registration in the ListTools response, specifying name, description, and input schema derived from Zod schema.

  {
  	name: TOOL_NAMES.textToJson,
  	description: `Converts groupped text from ${TOOL_NAMES.groupTextByJson} tool to JSON. This tool accepts a JSON template with placeholders and groupped text from ${TOOL_NAMES.groupTextByJson} tool.`,
  	inputSchema: zodToJsonSchema(TextToJsonSchema),
  },

• src/index.ts:69-71 (handler)

  Dispatcher case in the CallTool request handler that validates args and invokes the textToJsonTool handler.

  case TOOL_NAMES.textToJson:
  	const textToJsonArgs = args as TextToJsonSchemaType;
  	return textToJsonTool(textToJsonArgs.template, textToJsonArgs.text);

• src/common/constants.ts:8-8 (helper)

  Constant defining the tool name 'text-to-json' used in registration and dispatching.

  textToJson: "text-to-json",