Public chat API changelog

This page lists every version of the public chat API. The current version is 1.2. Minor versions add things and keep existing clients working. Major versions can break clients and come with a deprecation period. See the versioning and deprecation policy.

1.2 (2026-10-29)

Changed

• A session emptied by the workspace retention rule is now refused. Every session route answers 410 with message: "Session expired" and code: "SESSION_EXPIRED". Before, the session answered 200 with messages that had empty content.

Migration

• Handle 410 on a session route like 401: discard the stored session and create a new one. You can tell the user that the previous conversation expired.

1.1 (2026-10-22)

Added

• payload.variables on create a session: an agent can declare {{variables}} in its instructions, and the caller supplies their values at session start. Each value is substituted into the agent’s prompt before every reply.
• A declared variable without a caller value falls back to the default configured on the agent’s Embed tab.
• When a declared variable has neither a caller value nor a default, the session is refused with a 400 whose body carries code: "MISSING_PROMPT_VARIABLES" and the missing list of variable names.

Migration

• None. Existing clients keep working: payload.variables is optional, and agents that declare no {{variables}} behave exactly as before.

1.0 (2026-09-09)

Added

• First versioned release of the public chat API, under /public/v1/agents/{embedToken}/.
• Five routes: agent configuration, create a session, read a session, read MCP App card HTML, send a message and stream the reply.
• The reference page documents the routes, the server-sent events, the error codes, the CORS behavior and the limits.

Migration

• None. This is the first published version of the contract.