The Capacities MCP connector changes an object's name when you write to a custom property that is also called "Title."

Setup

Object type: Person Custom property: "Title" (rich text), used for job title Tools: getObjectTypeShape and updateObjectViaMD

Steps to reproduce

Add a custom rich-text property named "Title" to an object type. Call getObjectTypeShape for that type. It lists the custom property with the frontmatter key title_, which is separate from the built-in title (the object name). Call updateObjectViaMD on an object with:

title_: CEO

Read the object back with getObjectContent.

Expected: The custom "Title" property is "CEO." The object name does not change.

Actual: The object's name changes to "CEO." The custom "Title" property stays empty. Sending both title: and title_: CEO in the same call gives the same result.

Impact: The schema tool gives this key as the correct one to use, so AI agents that follow it rename records without warning.

Workaround: Rename the custom property, for example to "Role." The connector then gives it a key that does not clash (role), and writes go to the right field.

Possible related issue: Custom properties that clash with other built-in keys also get an underscore key. For example, a Meeting property "Type" gets type_. These may have the same bug. I have not tested this.