Discord forum channel broadcasts to all threads when thread ID is omitted

[ptone]

Bug Description

Platform: Discord integration

Context: Discord supports "forum channels" — a channel type where all conversation happens inside threads. Unlike regular text channels, forum channels require a thread ID to target a specific thread. Without one, the message has no valid single destination.

Current Behavior

When an agent (or user) sends a message to a Discord forum channel without specifying a thread ID, the integration currently broadcasts the message into every thread in that channel.

Expected Behavior

The integration should:

1. Detect when the target Discord channel is a forum channel
2. Require a thread ID when sending to a forum channel
3. Return an error to the sender if no thread ID is provided (rather than broadcasting)

Impact

Unintended message broadcast to all threads in a forum channel whenever thread ID is omitted — noisy and potentially confusing for all thread participants.

Root Cause Hypothesis

The integration likely doesn't distinguish between regular Discord text channels and forum channels when routing messages. For forum channels, the channel-to-project mapping needs to enforce thread ID presence.

Suggested Fix Scope

This applies when Scion channels are mapped to Discord forum channels. The fix likely involves:

• Detecting forum channel type at message routing time — the Discord API can identify channel type (forum channels are type 15)
• Enforcing thread ID requirement in the message handler for forum channels
• Returning a clear error if thread ID is missing for a forum-type channel