Add conversation attribute support to POST /data_attributes (Unstable)

[efassor]

Why?

Monolith PR intercom/intercom#485182 extends the POST /data_attributes endpoint to support creating conversation attributes via model: "conversation". The OpenAPI spec needs to be updated to document these new capabilities for SDK generation and developer documentation.

How?

Extends the Unstable spec with the new conversation model option, conversation-specific data types (list, decimal, relationship, files), and new request/response fields (multiline, list_options, reference). Also documents the PUT endpoint restriction for conversation attributes.

Implementation Plan

Plan: Document Conversation Attributes in POST /data_attributes

Context

PR intercom/intercom#485182 extends the POST /data_attributes endpoint to support creating conversation attributes via model: "conversation". This is an Unstable-only feature gated by the CreateConversationDataAttributes version change and a killswitch flag. The PUT /data_attributes/{id} endpoint is also updated to reject conversation attribute updates with a 400 error.

We need to update two downstream repos (Intercom-OpenAPI and developer-docs) to document these changes following the three-repo coordination pattern.

Changes

create_data_attribute_request schema

• model enum expanded: [contact, company, conversation]
• Added multiline boolean field to top-level properties
• Expanded "other type" branch with decimal and files
• Added "conversation list attribute" branch (data_type: list + required list_options)
• Added "conversation relationship attribute" branch (data_type: relationship + required reference)

data_attribute response schema

• model enum expanded to include conversation
• data_type enum expanded with decimal, datetime, list, relationship, files
• Added nullable response properties: multiline, list_options, reference

POST /data_attributes endpoint

• Updated description to mention conversation model
• Added conversation attribute success response example
• Added error examples: duplicate name, list options required, list options wrong type
• Added conversation request body examples (list, relationship, string)

PUT /data_attributes/{id} endpoint

• Added admonition about conversation attributes not being updatable
• Added error example for conversation attribute update attempt

_{Generated with Claude Code}