hermes - 💡(How to fix) Fix Discord thread backfill skipped when in_bot_thread is true (thread_require_mention=false) [3 pull requests]

Bug

When discord.thread_require_mention: false (or default, which is false), in_bot_thread evaluates to true for threads the bot has previously participated in. This bypasses the @mention requirement — but it also silently disables history backfill.

Root Cause

gateway/platforms/discord.py line 4671-4677:

_needed_mention = (
    require_mention
    and not is_free_channel
    and not in_bot_thread      # false when thread_require_mention=false
)
_backfill_enabled = self._discord_history_backfill()
if _needed_mention and _backfill_enabled:
    # backfill never runs for threads

Backfill is gated on _needed_mention, which requires in_bot_thread == false. But thread_require_mention: false (the default) sets in_bot_thread = true, so backfill always skips.

The condition conflates "mention was needed" with "backfill is needed" — they are separate concerns. A thread where the bot responds freely still benefits from backfilling recent thread history.

Steps to Reproduce

1. Default config: discord.thread_require_mention: false (or unset)
2. Bot has participated in a thread (so thread_id in self._threads)
3. User sends a message in that thread (with or without @mention)
4. Bot responds but has no thread context via backfill

Check gateway.log — no "fetching channel context" entries for thread messages.

Expected

Backfill runs for thread messages regardless of whether thread_require_mention is true or false. The backfill's purpose is to provide thread context, not just to fill the "mention gap".

Suggested Fix

gateway/platforms/discord.py line 4677 — change:

if _needed_mention and _backfill_enabled:

to:

if _backfill_enabled and (_needed_mention or is_thread):

This ensures threads always get backfill when history_backfill is enabled, independent of the mention gate.

Related

• #31467 — Discord auto-thread backfill fetches from parent channel instead of thread
• #16725 — Discord known-thread participation bypass cannot be disabled
• #23084 — discord.thread_require_mention YAML key is ignored (only env var works)
• #20742 — Add Discord strict mention mode for thread follow-ups