Basecamp MCP Server

Create Basecamp Check-in Answer

basecamp_create_answer

Create and post a new HTML answer to a specific Basecamp check-in question, grouped by date, so teams can submit daily or recurring check-in responses.

Instructions

Create a new answer for a check-in question. Content must be HTML.

Input Schema

TableJSON Schema

Name	Required	Description
`content`	Yes	HTML content of the answer. 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 <p>...</p>, and put <p><br></p> 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 <p> 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 <h2>, <h3>, <h4> as appropriate. * Inline code: <code>text</code>. Preformatted blocks: <pre>text</pre>. * Ordered lists: <ol><li>...</li></ol>. Unordered: <ul><li>...</li></ul>. * Tables: <table><tbody><tr><th>Heading</th>...</tr><tr><td>Cell</td>...</tr></tbody></table> * To mention a person: <bc-attachment person-id="{ person.id }"></bc-attachment>. Put the tag where the name must show in the text, for example "Thanks <bc-attachment person-id="123"></bc-attachment> 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: <bc-attachment sgid="{ attachment.attachable_sgid }"></bc-attachment> * Image gallery: wrap multiple <bc-attachment sgid="..." presentation="gallery"> in a <div>. * 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 <img> 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 <bc-attachment> 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: <mark style="background-color: var(--highlight-bg-N);">...</mark> * Text color highlights: <span style="color: var(--highlight-N);">...</span> * 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).
`group_on`	Yes	Date the answer belongs to (YYYY-MM-DD format, used to group answers by check-in day)
`question_id`	Yes	Question ID to answer

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.6.0Oct 7, 2026

changedInput schema / properties / content / description

Previous value: -"HTML content of the answer"New value: +"HTML content of the answer. \n\nHTML rules for content:\n\n* 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.\n* Wrap every paragraph in <p>...</p>, and put <p><br></p> 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 <p> 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.\n* Headings: use <h2>, <h3>, <h4> as appropriate.\n* Inline code: <code>text</code>. Preformatted blocks: <pre>text</pre>.\n* Ordered lists: <ol><li>...</li></ol>. Unordered: <ul><li>...</li></ul>.\n* Tables: <table><tbody><tr><th>Heading</th>...</tr><tr><td>Cell</td>...</tr></tbody></table>\n* To mention a person: <bc-attachment person-id=\"{ person.id }\"></bc-attachment>. Put the tag where the name must show in the text, for example \"Thanks <bc-attachment person-id=\"123\"></bc-attachment> 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).\n* Single image: <bc-attachment sgid=\"{ attachment.attachable_sgid }\"></bc-attachment>\n* Image gallery: wrap multiple <bc-attachment sgid=\"...\" presentation=\"gallery\"> in a <div>.\n* 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 <img> tag, so an external image URL can never be embedded directly: upload it, or accept that it stays a plain link.\n* Basecamp auto-enriches bc-attachment tags after saving (adds url, href, filename, content-type, etc.) — you never need to write those.\n* When you see an existing, already-enriched <bc-attachment> 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.\n* Background highlights: <mark style=\"background-color: var(--highlight-bg-N);\">...</mark>\n* Text color highlights: <span style=\"color: var(--highlight-N);\">...</span>\n* 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).\n"

Changed2 schema fields changedv1.2.1Jun 19, 2026

removedInput schema / properties / bucket_id

Removed value: -{
-  "description": "Project/bucket ID",
-  "type": "number"
-}

changedInput schema / required

Previous value: -[
-  "bucket_id",
-  "question_id",
-  "content",
-  "group_on"
-]New value: +[
+  "question_id",
+  "content",
+  "group_on"
+]

Addedv1.0.3Apr 29, 2026

TDQS

B3.3/5.0

Behavior3/5

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

Annotations already declare this is a non-read-only, non-idempotent, non-destructive, open-world write. The description adds one genuinely useful behavioral constraint — content must be HTML — but says nothing about whether an answer is appended to an existing one, whether the author is the caller, or what happens on error. With annotations carrying the safety profile, a 3 fits.

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

Conciseness5/5

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

Two short sentences, purpose first, constraint second, no filler. Nothing to trim and the key requirement is front-loaded.

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

Completeness3/5

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

For a write tool with no output schema, the description is thin: it never says what a successful call returns (e.g., the new answer ID) or how errors surface, and it omits the relationship between group_on and the check-in day grouping beyond the schema's own note. Annotations plus the rich schema keep it callable, but the description itself is only adequate.

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

Parameters3/5

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

Schema description coverage is 100%, with the content parameter carrying an extremely detailed HTML spec and group_on explaining the YYYY-MM-DD grouping semantics. The description repeats only the HTML requirement and adds no meaning beyond the schema, so the baseline 3 applies.

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

Purpose4/5

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

States a specific verb and resource ("Create a new answer") and scopes it to a check-in question, which separates it from create_comment, create_message, and the read-side list_answers/get_answer siblings. It is clear but does not explicitly name any alternative tool or contrast with them.

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

Usage Guidelines2/5

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

There is no guidance on when to use this tool versus basecamp_update_answer-like siblings (update path isn't present, but update_comment exists) or versus create_comment, and no prerequisites such as needing a valid question_id from list_questions. Usage is only implied by "for a check-in question."

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

Deploy Server

Create Basecamp Check-in Answer

Instructions

Input Schema

Schema Changelog

TDQS

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