Update Basecamp Message
basecamp_update_messageModify a Basecamp message by replacing its content or using efficient partial operations (append, prepend, search-replace) to save token usage.
Instructions
Update a message. Use partial content operations when possible to save on token usage.
HTML rules for content:
Allowed tags: p, span, h2, h3, h4, br, strong, em, strike, code, a (with href attribute), pre, ol, ul, li, blockquote, mark, figure, figcaption, table, tbody, tr, th, td, div, bc-attachment.
Use for paragraphs. Use for empty line spacing between paragraphs.
Headings: use , , as appropriate.
Inline code: text. Preformatted blocks: text.
Ordered lists: .... Unordered: ....
Tables: Heading...Cell...
To mention people:
Single image:
Image gallery: wrap multiple in a .
Basecamp auto-enriches bc-attachment tags after saving (adds url, href, filename, content-type, etc.) — you never need to write those.
To consume less tokens, existing tags can be rewritten keeping only: sgid, presentation, caption. For mentions also keep content-type="application/vnd.basecamp.mention". Drop everything else including inner HTML.
Background highlights: ...
Text color highlights: ...
For both, N is 1 (yellow), 2 (amber), 3 (red), 4 (pink), 5 (purple), 6 (blue), 7 (teal), 8 (near-white), or 9 (light gray).
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| message_id | Yes | Basecamp resource identifier | |
| subject | No | New message subject | |
| message_type_id | No | Optional message type/category ID | |
| content | No | If provided, replaces entire HTML content. Cannot be used with content_append, content_prepend, or search_replace. | |
| content_append | No | Text to append to the end of current content. Cannot be used with content. | |
| content_prepend | No | Text to prepend to the beginning of current content. Cannot be used with content. | |
| search_replace | No | Array of search-replace operations to apply to current content. Cannot be used with content. |