OSRS MCP Server

Instructions

Implementation Reference

• index.ts:190-211 (handler)

  The main handler function that executes the get_file_details tool logic, retrieving file existence, size, line count, and timestamps from the data directory.

  async function getFileDetails(filename: string): Promise<any> {
      try {
          const filePath = path.join(getDataDir(), filename);
          if (!fs.existsSync(filePath)) {
              return { exists: false };
          }
  
          const stats = await fs.promises.stat(filePath);
          const lineCount = await getFileLineCount(filePath);
  
          return {
              exists: true,
              size: stats.size,
              lineCount,
              created: stats.birthtime,
              lastModified: stats.mtime
          };
      } catch (error) {
          console.error(`Error getting file details for ${filename}:`, error);
          return { exists: false, error: 'Error getting file details' };
      }
  }

• index.ts:65-67 (schema)

  Zod schema defining the input validation for the get_file_details tool (filename parameter).

  const FileDetailsSchema = z.object({
      filename: z.string().describe("The filename to get details for in the data directory")
  });

• index.ts:370-372 (registration)

  Tool registration in the getToolDefinitions() function, listing get_file_details as an available tool.

      name: "get_file_details",
      description: "Get details about a file in the data directory.",
  },

• index.ts:473-483 (registration)

  Registration and dispatching logic in the main CallToolRequestSchema handler switch, validating arguments and invoking the getFileDetails handler.

  case "get_file_details":
      const detailsArgs = getSchemaForTool(name).parse(args) as { filename: string };
      const { filename: detailsFilename } = detailsArgs;
      
      // Security check to prevent directory traversal
      if (detailsFilename.includes('..') || detailsFilename.includes('/') || detailsFilename.includes('\\')) {
          throw new Error('Invalid filename');
      }
      
      const details = await getFileDetails(detailsFilename);
      return responseToString(details);

• index.ts:218-232 (helper)

  Helper function used by getFileDetails to count the number of lines in a file efficiently using streams.

  async function getFileLineCount(filePath: string): Promise<number> {
      return new Promise((resolve, reject) => {
          let lineCount = 0;
          const stream = fs.createReadStream(filePath);
          stream.on('data', (chunk) => {
              for (let i = 0; i < chunk.length; i++) {
                  if (chunk[i] === 10) { // ASCII code for newline
                      lineCount++;
                  }
              }
          });
          stream.on('end', () => resolve(lineCount));
          stream.on('error', reject);
      });
  }