/**
* Image utility helpers for MCP image content blocks
*/
import axios from 'axios';
/**
* Fetch an image from a URL and return its base64-encoded data + MIME type.
* Returns null on any error (image embedding is always best-effort).
*/
export async function fetchImageAsBase64(
url: string
): Promise<{ data: string; mimeType: string } | null> {
try {
const response = await axios.get<ArrayBuffer>(url, {
responseType: 'arraybuffer',
timeout: 15_000,
headers: { Accept: 'image/*' },
});
const buffer = Buffer.from(response.data);
const base64 = buffer.toString('base64');
const rawContentType = (response.headers['content-type'] as string | undefined) ?? '';
const mimeType = rawContentType.split(';')[0].trim() || inferMimeFromUrl(url);
return { data: base64, mimeType };
} catch {
return null;
}
}
function inferMimeFromUrl(url: string): string {
const path = url.split('?')[0].toLowerCase();
if (path.endsWith('.gif')) return 'image/gif';
if (path.endsWith('.jpg') || path.endsWith('.jpeg')) return 'image/jpeg';
if (path.endsWith('.webp')) return 'image/webp';
return 'image/png';
}
/**
* Build an MCP image content block from base64 data.
*/
export function imageContentBlock(data: string, mimeType: string) {
return { type: 'image' as const, data, mimeType };
}
