Create a new DRAFT post. account_id comes from postey://accounts, which lists every account the caller can access, and is the account the user confirmed for this post, including when only one account exists. postey://platforms/{platform}/rules lists each platform's required, optional and forbidden content fields. One create_post call covers every platform for a topic: platform and contents for the first platform, additional_platforms=[{platform, contents}, ...] for the rest. All of them share one post_id, which cross-platform grouping, scheduling and analytics rely on. Separate create_post calls for the same topic create separate post_ids that cannot be grouped, scheduled or managed together. Example: create_post(platform=X, contents=[...], additional_platforms=[{platform: LINKEDIN, contents: [...]}, {platform: INSTAGRAM, contents: [...]}]). convert_post_content is for explicit requests to auto-adapt content, not for multi-platform creation. The compose-post prompt covers each target platform, and content has to fit the platform's hard limit (validate_post_content checks it). tags=[...] attaches tags inline, without separate add_tag calls. postey://accounts/{account_id}/tags lists existing tags; reusing an existing name with its exact casing attaches that tag.
