feat(discord): sync thread names from session titles

[yshen92]

What does this PR do?

Fixes #18430.

Hermes-created Discord threads already get generated session titles, but the visible Discord thread name stays as the original user-message snippet. That makes Discord's native thread list hard to scan because threads keep cryptic or truncated names even after Hermes has a better session title.

This PR syncs Hermes-generated session titles to visible Discord thread names, behind an opt-in config gate. It reuses the existing session-title flow and the existing maybe_auto_title(..., title_callback=...) seam. It does not add a new model tool, model schema, or environment variable.

Mapping to #18430

Issue requirement	Where implemented
Config option to enable the behavior	discord.auto_rename_threads.enabled, default false
Detect title generation after maybe_auto_title	Existing title_callback seam; agent/title_generator.py untouched
Sanitize/truncate to Discord's 100-char thread-name limit	Gateway sanitizer plus adapter-level cap (defense in depth); values above 100 clamped
Graceful failure without permissions / archived threads	Three-layer error isolation; a rename failure cannot interrupt response delivery
Guardrail: conservative default (off)	Disabled by default; zero behavior change for existing deployments
Guardrail: /title renames only behind a separate option	sync_title_command, default false (requires enabled: true and mode: session_title)
Guardrail: don't overwrite manually renamed threads	Not implemented in this PR — see Limitations

Limitations

This PR renames the thread whenever a session title is generated while the feature is enabled; it does not detect that a user manually renamed the thread in the meantime. This is a deliberate scope cut to keep the diff minimal and avoid per-thread initial-name state. If maintainers want the guard in this PR, I'm happy to add an initial-name check as a follow-up commit; #35420's thread_initial_name approach shows one viable shape.

Relationship to existing Discord thread-title PRs

Several PRs target #18430 or adjacent thread-naming behavior. This PR is the narrow, strictly opt-in implementation of the issue's proposed solution.

• feat(discord): sync thread titles with session titles #35420 (open): closest prior work. Session-title sync with a default-on summary mode, new environment variables, bidirectional Discord-to-session title sync, an initial-name guard, and changes to the platform base interface and title-generator internals. This PR is strictly opt-in per the issue's guardrails, keeps all config in config.yaml with no env vars, and does not touch agent/title_generator.py, session internals, or the platform base interface. Smaller reviewable surface: one commit on the existing callback seam.
• feat(gateway/discord): sync thread names with session titles #15757 (open): also syncs generated session titles and /title to Discord thread names, but polls the session DB (up to 15s latency) against an older gateway layout. This PR is event-driven via the existing callback and targets the current plugin-based Discord adapter layout.
• feat(discord): auto-rename threads from session titles + periodic retitle #29983 (open): auto-rename plus periodic retitling. This PR performs a single rename per title generation, avoiding recurring edit traffic against Discord's channel-edit rate limit.
• feat(discord): sync thread names from session titles #26477 and feat(gateway): add cross-platform update_topic_title to base adapter #30559: additional attempts in the same area (referenced in the feat(discord): auto-rename generic thread titles #33862 discussion); listed for completeness.
• feat(discord): add opt-in smart auto-retitling for threads #13915 (closed): combined smarter initial thread names with post-first-exchange retitling behind an env-var-facing gate. This PR keeps the scope narrower: session-title sync only, no new env var, disabled defaults.
• feat(discord): generate auto-thread titles #3009 (closed): generates a better Discord thread name before creating the thread. This PR updates the thread after Hermes has generated the session title, so it is not a pre-create title-generation path.
• feat(discord): auto-rename generic thread titles #33862 (open): deterministic ingress cleanup for generic/truncated thread names, no model/session-title dependency. Complementary: feat(discord): auto-rename generic thread titles #33862 improves initial names, this PR syncs generated titles afterward. The two can coexist if config names/modes stay compatible.

So the claim is not "nobody has proposed this." The claim is "this is the current, tested, strictly opt-in implementation matching the issue's proposed guardrails, with the smallest blast radius of the open attempts."

Related Issue

Fixes #18430

Related: #35420, #15757, #29983, #26477, #30559, #13915, #3009, #33862

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• gateway/run.py
  • Detects Discord thread lanes and schedules best-effort title sync through the existing generated-title callback path.
  • Keeps response delivery isolated from Discord rename failures.
• plugins/platforms/discord/adapter.py
  • Adds DiscordAdapter.rename_thread(thread_id, name).
  • Resolves thread/channel IDs with get_channel first and fetch_channel fallback.
  • Handles invalid IDs, permission/API errors, archived/locked threads, and unexpected exceptions without propagating into the response path.
• gateway/slash_commands.py
  • Extends /title Name so manual session titles can also sync the visible Discord thread name when explicitly enabled.
  • Leaves read-only /title behavior unchanged.
• gateway/config.py, hermes_cli/config.py, cli-config.yaml.example
  • Adds discord.auto_rename_threads config with disabled defaults:

discord:
  auto_rename_threads:
    enabled: false
    mode: session_title
    sync_title_command: false
    max_length: 100

• website/docs/user-guide/messaging/discord.md
  • Documents the opt-in config, /title coupling, 100-character Discord name cap, and rate-limit considerations.
• Tests
  • Adds Discord title-sync coverage, /title coverage (including a test that exercises the real /title → scheduler → adapter path, RED on pre-fix code), config-default coverage, adversarial cases (invalid thread IDs, missing adapter/client, cache-miss fetch fallback), and regression checks for existing Discord/Telegram behavior.

How to Test

Automated checks run locally:

scripts/run_tests.sh \
  tests/gateway/test_discord_thread_title_rename.py \
  tests/gateway/test_title_command.py \
  tests/test_gateway_streaming_nested_config.py \
  tests/gateway/test_discord_slash_commands.py \
  tests/gateway/test_telegram_topic_mode.py

Result:

122 passed, 0 failed

Syntax check:

python -m py_compile \
  gateway/run.py \
  gateway/slash_commands.py \
  gateway/config.py \
  hermes_cli/config.py \
  plugins/platforms/discord/adapter.py

Result:

PASS

Manual rollout check performed on a Discord gateway instance after enabling:

discord:
  auto_rename_threads:
    enabled: true
    mode: session_title
    sync_title_command: true
    max_length: 100

Verified behavior:

1. A newly created Discord auto-thread was renamed from the initial message snippet to the generated Hermes session title.
2. /title Manual English Title updated both the stored Hermes session title and the visible Discord thread name.
3. Gateway stayed active after restart and did not report fatal rename errors.

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate (see Relationship section)
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: Ubuntu/Linux gateway service with Discord enabled

Note: I ran the targeted gateway/config regression suite above, not the full pytest tests/ -q suite.

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

Screenshots / Logs

No screenshots attached to keep the PR focused on code and tests.

Relevant verification summary:

122 passed, 0 failed
py_compile PASS
gateway rollout verified locally with Discord thread rename and /title rename

Privacy/data guardrails

• No outbound telemetry, analytics, or third-party identifier tagging.
• Uses the existing Discord bot token already configured for the gateway. No new credentials.
• Session title generation behavior is unchanged and stays in the existing agent/title_generator.py path.
• No user PII is sent beyond what the bot already sends in normal Discord message delivery.
• Config defaults are disabled, so no existing Discord server is affected unless an operator explicitly opts in.
• No .env variable added. Behavioral config lives in config.yaml.

[teknium1]

Fixed via #60187 (salvage of #56792 by @rungmc357). We went with the default-on, guard-based approach (matching how Telegram topic rename shipped) over a config gate. Thanks for the thorough config plumbing and tests!