exif-mcp

Instructions

Implementation Reference

• src/tools/index.ts:69-84 (handler)

  The core handler function for the 'read-metadata' tool. Loads image buffer using loadImage, builds exifr options from segments using buildOptions, parses metadata with exifr.parse, returns success response with metadata JSON or error.
  async (args, extra) => { try { const { image, segments } = args; const buf = await loadImage(image); const opts = buildOptions(segments as any); const meta = await exifr.parse(buf, opts); if (!meta || Object.keys(meta).length === 0) { return createErrorResponse('No metadata found in image'); } return createSuccessResponse(meta); } catch (error) { return createErrorResponse(`Error reading metadata: ${error instanceof Error ? error.message : String(error)}`); } }
• src/tools/index.ts:54-68 (schema)

  Input schema definition: ImageSourceSchema (zod object for image source kinds) and segments (optional array of specific metadata segments enum). Used in server.tool call.
  const ImageSourceSchema = z.object({ kind: z.enum(['path', 'url', 'base64', 'buffer']), path: z.string().optional(), url: z.string().optional(), data: z.string().optional(), buffer: z.string().optional() }); // Tool 1: read-metadata - reads all or specified metadata segments from an image const readMetadataTool = server.tool('read-metadata', "Read all or specified metadata segments from an image", { image: ImageSourceSchema, segments: z.array(z.enum(['EXIF', 'GPS', 'XMP', 'ICC', 'IPTC', 'JFIF', 'IHDR'])).optional() },
• src/tools/index.ts:63-86 (registration)

  Registration of the 'read-metadata' tool via server.tool() with name, description, input schema, and handler function. Reference stored in tools object.
  const readMetadataTool = server.tool('read-metadata', "Read all or specified metadata segments from an image", { image: ImageSourceSchema, segments: z.array(z.enum(['EXIF', 'GPS', 'XMP', 'ICC', 'IPTC', 'JFIF', 'IHDR'])).optional() }, async (args, extra) => { try { const { image, segments } = args; const buf = await loadImage(image); const opts = buildOptions(segments as any); const meta = await exifr.parse(buf, opts); if (!meta || Object.keys(meta).length === 0) { return createErrorResponse('No metadata found in image'); } return createSuccessResponse(meta); } catch (error) { return createErrorResponse(`Error reading metadata: ${error instanceof Error ? error.message : String(error)}`); } } ); tools['read-metadata'] = readMetadataTool;
• src/tools/loaders.ts:11-72 (helper)

  loadImage helper: asynchronously loads image data from path, URL (http/file), base64 data URI or raw, or base64 buffer into Buffer/Uint8Array. Handles errors and size limits.
  export async function loadImage(src: ImageSourceType): Promise<Buffer | Uint8Array> { try { switch (src.kind) { case 'path': if (!src.path) { throw new Error('Path is required for kind="path"'); } return await fs.promises.readFile(src.path); case 'url': if (!src.url) { throw new Error('URL is required for kind="url"'); } if (src.url.startsWith('file://')) { // Handle file:// URLs by converting to filesystem path const filePath = fileURLToPath(src.url); return await fs.promises.readFile(filePath); } else { // Handle HTTP/HTTPS URLs const response = await fetch(src.url); if (!response.ok) { throw new Error(`Failed to fetch URL: ${response.status} ${response.statusText}`); } return new Uint8Array(await response.arrayBuffer()); } case 'base64': if (!src.data) { throw new Error('Data is required for kind="base64"'); } // Check for potential oversized base64 string (>30MB) if (src.data.length > 40000000) { // ~30MB in base64 throw new Error('PayloadTooLarge: Base64 data exceeds 30MB limit'); } // Handle data URIs or raw base64 if (src.data.startsWith('data:')) { const base64Data = src.data.split(',')[1]; return Buffer.from(base64Data, 'base64'); } else { return Buffer.from(src.data, 'base64'); } case 'buffer': if (!src.buffer) { throw new Error('Buffer is required for kind="buffer"'); } return Buffer.from(src.buffer, 'base64'); default: // This should never happen due to type constraints, but TypeScript needs it throw new Error(`Unsupported image source kind: ${(src as any).kind}`); } } catch (error) { if (error instanceof Error) { throw new Error(`Failed to load image: ${error.message}`); } throw error; } }
• src/tools/segments.ts:24-73 (helper)

  buildOptions helper: creates exifr.parse options enabling all segments by default or only specified ones (EXIF/GPS via 'tiff', XMP, ICC, IPTC, JFIF, IHDR).
  export function buildOptions(segments?: SegmentType[]): ExifrOptions { // Default options - include everything if segments not specified if (!segments || segments.length === 0) { return { tiff: true, // Includes EXIF and GPS xmp: true, icc: true, iptc: true, jfif: true, ihdr: true, }; } // Start with all segments disabled const options: ExifrOptions = { tiff: false, xmp: false, icc: false, iptc: false, jfif: false, ihdr: false, }; // Enable requested segments segments.forEach(segment => { switch (segment) { case 'EXIF': case 'GPS': options.tiff = true; break; case 'XMP': options.xmp = true; break; case 'ICC': options.icc = true; break; case 'IPTC': options.iptc = true; break; case 'JFIF': options.jfif = true; break; case 'IHDR': options.ihdr = true; break; } }); return options; }