AI Alt Text for the Fediverse

Generate image alt text for Mastodon with your own Claude API key. Accessibility best practices, privacy-first.

A privacy-first Chrome extension that adds an AI alt-text button to the Mastodon web composer (any instance, including self-hosted). When you open the image description (alt-text) modal, the extension can send the image to Anthropic’s Claude API — using your own API key — and autofill a concise, screen-reader-friendly description that follows established alt-text accessibility best practices. - Accessibility best practices built in: Claude is prompted with established alt-text best practices (aligned with W3C WAI image guidance), so the output is written for real assistive-technology users. - Bring-your-own-key: You enter your own Anthropic API key. There is no developer key anywhere in the code. - Nothing leaves your device except the image you choose to describe, which goes only to api.anthropic.com. No analytics, no telemetry, no “phone home.” - Minimal permissions: Host access is requested per-instance, only for the Mastodon sites you add.