We publish through the v2 API (media upload + drafts). There’s currently no way to set image alt text programmatically: the media upload has no alt field, the media endpoint is GET-only, and the drafts schema doesn’t carry one. Our automated workflow ends with someone pasting alt text by hand in the editor before publishing.
Proposal: expose a writable alt_text on media, either at upload or via PATCH /v2/social-sets/{social_set_id}/media/{media_id}. The web editor already supports per-image descriptions, so this would let API-created posts ship accessible by default and remove the last manual step in our pipeline.
