Basecamp MCP Server

Update Kanban Card

basecamp_update_kanban_card

Update a Basecamp kanban card's title, due date, assignees, content, or steps, using partial edits to change content without replacing the whole card.

Instructions

Update a kanban card including its steps. At least one field (title, content, partial content operations, or steps) must be provided. 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.
Wrap every paragraph in ..., and put between one paragraph and the next. Both parts are necessary: newlines and blank lines in your HTML are discarded, and Basecamp shows no space around a on its own, so two paragraphs with nothing between them are shown as one block of text. Do not rely on line breaks in your HTML to separate paragraphs.
Headings: use , , as appropriate.
Inline code: text. Preformatted blocks: text.
Ordered lists: .... Unordered: ....
Tables: Heading...Cell...
To mention a person: . Put the tag where the name must show in the text, for example "Thanks for the fix". The person gets a notification. If the ID is not a person, the tool returns an error and writes nothing. Get person IDs from basecamp_list_people, or from the people in other responses (assignees, creators).
Single image:
Image gallery: wrap multiple in a .
A bc-attachment needs an attachable_sgid. For a file that is already in Basecamp, take the sgid from the HTML content of the message, comment or card that shows it, or use basecamp_list_recordings. For a file that is not in Basecamp yet, such as an image at an external URL or a screenshot on disk, upload it with basecamp_create_attachment and use the sgid that it returns. There is no tag, so an external image URL can never be embedded directly: upload it, or accept that it stays a plain link.
Basecamp auto-enriches bc-attachment tags after saving (adds url, href, filename, content-type, etc.) — you never need to write those.
When you see an existing, already-enriched tag (e.g. from a previous list/get call), leave its inner HTML alone. Before any content_append/content_prepend/search_replace runs, it is automatically collapsed back to its minimal form (sgid, presentation, caption, and content-type for mentions) — you don't need to strip it yourself, and doing so manually is unnecessary and risks mismatched find strings.
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

TableJSON Schema

Name	Required	Description
`steps`	No	Complete array of desired steps. Array order defines position. Steps not in array will be deleted.
`title`	No	New card title
`due_on`	No	Due date (YYYY-MM-DD format) or null to clear
`card_id`	Yes	Basecamp resource identifier
`content`	No	If provided, replaces entire HTML content. Cannot be used with content_append, content_prepend, or search_replace.
`assignee_ids`	No	Array of user IDs to assign to the card
`content_append`	No	Text to append to the end 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.
`content_prepend`	No	Text to prepend to the beginning of current content. Cannot be used with content.

Schema Changelog

Changes observed during successful MCP inspections.

Changed12 schema fields changedv1.2.1Jun 19, 2026
- addedInput schema / properties / assignee_ids / items / $ref
```
Added value: +"#/properties/card_id"
```
- removedInput schema / properties / assignee_ids / items / type
```
Removed value: -"number"
```
- removedInput schema / properties / bucket_id
```
Removed value: -{
-  "description": "Basecamp resource identifier",
-  "type": "number"
-}
```
- removedInput schema / properties / card_id / $ref
```
Removed value: -"#/properties/bucket_id"
```
- addedInput schema / properties / card_id / description
```
Added value: +"Basecamp resource identifier"
```
- addedInput schema / properties / card_id / type
```
Added value: +"number"
```
- removedInput schema / properties / notify
```
Removed value: -{
-  "description": "Whether to notify assignees of the update",
-  "type": "boolean"
-}
```
- addedInput schema / properties / steps / items / properties / assignee_ids / items / $ref
```
Added value: +"#/properties/card_id"
```
- removedInput schema / properties / steps / items / properties / assignee_ids / items / type
```
Removed value: -"number"
```
- addedInput schema / properties / steps / items / properties / id / $ref
```
Added value: +"#/properties/card_id"
```
- removedInput schema / properties / steps / items / properties / id / type
```
Removed value: -"number"
```
- changedInput schema / required
```
Previous value: -[
-  "bucket_id",
-  "card_id"
-]New value: +[
+  "card_id"
+]
```
Addedv1.0.0Jan 4, 2026

TDQS

A4.2/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well past the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=true) by disclosing error behavior ('If the ID is not a person, the tool returns an error and writes nothing'), server-side auto-enrichment of bc-attachment tags, and the automatic collapsing of enriched tags before append/prepend/search_replace so callers don't strip manually. It does not warn that the steps array is a full replacement whose omissions are deleted, which is the main destructive behavior of this tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness3/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose, precondition, and the token-saving tip are correctly front-loaded, and the bulleted HTML list is scannable. However, the HTML reference is roughly ten bullets of format documentation that dwarf the actual update semantics, and parts (color index table, gallery syntax) are reference material rather than decision-relevant guidance.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 9-parameter mutation tool with nested step objects and no output schema, the description covers the hardest thing to get right (valid HTML content format) thoroughly and names the helper tools for IDs and attachments. The notable omission is that replacing 'steps' silently deletes steps not resent, which an agent should be warned about before calling.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3, but the description adds real semantics the schema lacks: the full allowed HTML tag set, required paragraph wrapping and <p><br></p> separator rules, mention/gallery syntax, and the highlight variable convention. The mutual-exclusion rules are restated from the schema rather than extended.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource immediately: 'Update a kanban card including its steps.' This is clearly distinguishable from the adjacent siblings create_kanban_card, move_kanban_card, get_kanban_card, and list_kanban_cards without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides a hard precondition ('At least one field must be provided') and a clear preference rule ('Use partial content operations when possible to save on token usage'). It also routes the agent to basecamp_list_people, basecamp_list_recordings, and basecamp_create_attachment for the supporting data HTML needs. It never states when to use this instead of basecamp_move_kanban_card or basecamp_update_todo, so exclusions are absent.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

Update Kanban Card

Instructions

Input Schema

Schema Changelog

TDQS

Other Tools