messaging

The Teams messaging endpoint’s turn: what happens between Azure Bot Service POSTing an activity and a card appearing in the channel.

Split out from conversation.ts because the two callers have genuinely different contracts. conversation.ts runs a turn and RETURNS the reply, which is what a direct HTTP caller (or the in-repo preview UI) wants. A real channel cannot work that way: Bot Service ignores the response body and expects a fast 200, so this module acknowledges first and delivers the reply out-of-band through the Connector API.

The sequence for a message activity:

1. validate the inbound JWT and pin the reply destination to the token’s serviceUrl (see auth.ts);
2. return 200 immediately - Bot Service retries an activity it thinks timed out, and a duplicate turn means a duplicate card;
3. show the typing indicator, run the agent, and POST the card back.

Step 2 is why this is fire-and-forget rather than awaited: a card-producing agent turn takes seconds to tens of seconds, far longer than the ~15s Bot Service allows a bot to acknowledge.

Interfaces

• BotCredentials
• DeliverTurnOptions

Functions

• deliverTurn
• resolveServiceUrl