hermes-agent/gateway/platforms
snav e84fe483bc feat(discord): channel history backfill for multi-user sessions
Adds optional channel-context backfill for Discord shared-channel sessions
so the agent can see recent messages it missed between its own turns
(typically when require_mention=true filters out most traffic).

Previously the agent only saw the @mention message that triggered it, which
led to disorienting replies in active multi-user channels where the
conversation context was invisible. With backfill enabled, a configurable
number of recent messages are fetched per-turn and prepended to the trigger
message as a context block, kept separate from sender-prefix logic so
attribution remains clean.

This re-opens the work from #13063 (approved by @OutThisLife on 2026-04-20,
closed when I closed the branch to address the simpolism:main head-branch
issue plus an ordering bug I caught later in live use). Filing against the
freshly-rewritten problem statement in #13054 so the design is grounded in
the failure mode rather than the implementation shape.

The implementation follows the **push-mode last-self-anchored** design from
the two options laid out in #13054. See the issue for the trade-off
discussion vs pull-mode (#13120 was an earlier closed PR using that shape).
Treating this as a reference implementation — happy to rewrite as
last-trigger anchoring or as a hybrid with #13120 if maintainers prefer.

Changes:

- gateway/platforms/discord.py:
  - new `_discord_history_backfill()` / `_discord_history_backfill_limit()`
    helpers (config.extra > env > default), mirroring the existing
    `_discord_require_mention()` shape
  - new `_fetch_channel_context()` that scans `channel.history()` backwards
    from the trigger to the bot's last message (or limit), formats as
    `[Recent channel messages] / [name] msg / ...`, respects DISCORD_ALLOW_BOTS,
    skips system messages
  - per-channel `_last_self_message_id` cache to narrow the fetch window
    on hot paths (avoids full history scan when the bot has spoken recently)
  - **IMPORTANT**: passes `oldest_first=False` explicitly to `channel.history()`.
    discord.py 2.x silently flips the default to True when `after=` is supplied,
    which would select the EARLIEST N messages after our last response instead
    of the LATEST N before the trigger. In high-traffic windows this would
    return stale tool traces and drop the actual final answer the user is
    asking about. See regression test below. Caught in live use during a
    Codex tool-trace burst on May 13 2026.
- gateway/config.py: discord_history_backfill + discord_history_backfill_limit
  settings + yaml→env bridge
- gateway/platforms/base.py: channel_context field on MessageEvent
- gateway/run.py: prepend channel_context after sender-prefix so the
  [sender name] tag applies to the trigger message alone, not to the backfill
- hermes_cli/config.py: defaults for new discord.history_backfill and
  discord.history_backfill_limit keys
- cli-config.yaml.example: documented defaults
- tests/gateway/test_discord_free_response.py: 7 new tests covering
  cold-start backfill, self-message stop boundary, other-bot filtering,
  cache hot-path narrowing, stale-cache fallback, shared-channel +
  per-user backfill paths, and the ordering regression test
  (`test_fetch_channel_context_cache_uses_latest_window_when_after_set`)
- tests/gateway/test_config.py: yaml→env bridge tests
- tests/gateway/test_session.py: prefix-order edge cases
- website/docs/user-guide/messaging/discord.md: env vars + config keys +
  usage docs

Tested on Ubuntu 24.04 — empirically validated in my own multi-bot Discord
research server for the past three weeks.

Fixes #13054
Supersedes #13063 (closed)
2026-05-14 15:50:57 -07:00
..
qqbot fix(gateway): keep QQBot reconnect loop alive 2026-05-13 23:13:25 -07:00
__init__.py perf(gateway): defer QQAdapter and YuanbaoAdapter imports via PEP 562 (#22790) 2026-05-09 13:17:48 -07:00
_http_client_limits.py fix(gateway): tighten httpx keepalive and close whatsapp typing-response leak (#18451) 2026-05-02 02:23:37 -07:00
ADDING_A_PLATFORM.md refactor(plugins): add apply_yaml_config_fn registry hook 2026-05-13 22:20:30 -07:00
api_server.py fix(gateway): enqueue SSE EOS sentinel on task completion 2026-05-12 15:04:54 -07:00
base.py feat(discord): channel history backfill for multi-user sessions 2026-05-14 15:50:57 -07:00
bluebubbles.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
dingtalk.py fix(gateway): add lazy_deps.ensure() to slack, matrix, dingtalk, feishu adapters (#25014) 2026-05-13 19:28:50 +05:30
discord.py feat(discord): channel history backfill for multi-user sessions 2026-05-14 15:50:57 -07:00
email.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
feishu.py fix(gateway): make Feishu ws connect override sync to preserve context manager 2026-05-13 23:12:34 -07:00
feishu_comment.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
feishu_comment_rules.py chore: ruff auto-fix C401, C416, C408, PLR1722 (#23940) 2026-05-11 11:20:58 -07:00
helpers.py chore: ruff auto-fixes — collapsible-else-if, if-stmt-min-max, dict.fromkeys (#23926) 2026-05-11 11:03:29 -07:00
homeassistant.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
matrix.py fix(gateway): complete lazy-install rebind for slack/feishu/matrix + add ensure_and_bind helper (#25038) 2026-05-14 10:41:46 +05:30
mattermost.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
msgraph_webhook.py fix(msgraph_webhook): harden auth surface + IP allowlisting + response hygiene 2026-05-08 10:29:58 -07:00
signal.py fix(signal): handle group messages from linked devices in syncMessage path 2026-05-12 18:43:26 -07:00
signal_rate_limit.py feat(gateway/signal): add support for multiple images sending 2026-04-30 04:28:08 -07:00
slack.py fix(gateway): complete lazy-install rebind for slack/feishu/matrix + add ensure_and_bind helper (#25038) 2026-05-14 10:41:46 +05:30
sms.py test(sms): use clear=True in test_missing_phone_number_is_non_retryable 2026-05-04 05:25:09 -07:00
telegram.py fix(telegram): set REQUIRES_EDIT_FINALIZE so final MarkdownV2 edit is not skipped 2026-05-14 14:51:07 -07:00
telegram_network.py chore: ruff auto-fix C401, C416, C408, PLR1722 (#23940) 2026-05-11 11:20:58 -07:00
webhook.py fix(webhook): widen INSECURE_NO_AUTH loopback check + tests + docs 2026-05-07 07:38:43 -07:00
wecom.py fix(wecom): update connection status after WebSocket reconnection 2026-05-12 18:48:17 -07:00
wecom_callback.py fix(gateway): tighten httpx keepalive and close whatsapp typing-response leak (#18451) 2026-05-02 02:23:37 -07:00
wecom_crypto.py feat(gateway): add WeCom callback-mode adapter for self-built apps 2026-04-11 15:22:49 -07:00
weixin.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
whatsapp.py fix(whatsapp): drop status broadcasts and channel newsletters before agent dispatch (#25845) 2026-05-14 09:59:03 -07:00
yuanbao.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
yuanbao_media.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
yuanbao_proto.py chore: ruff auto-fix PLR6201 — tuple → set in membership tests (#23937) 2026-05-11 11:13:25 -07:00
yuanbao_sticker.py yuanbao platform (#16298) 2026-04-26 18:50:49 -07:00