feat(cron/slack): flat in-channel continuable cron delivery surface

[hashbender]

Summary

Adds a per-platform cron_continuable_surface config key so a continuable cron job can deliver flat into a Slack channel — no dedicated thread — and still be replied-to and continued in context.

Today continuable cron (cron.mirror_delivery / per-job attach_to_session) is thread-preferred: on any thread-capable platform it unconditionally mints a hidden handoff thread (cron/scheduler.py). There was no "continuable but flat" mode. This adds one.

How it works

cron_continuable_surface takes "thread" (default, byte-identical to today) or "in_channel". In in_channel mode the scheduler skips the thread-open branch (leaves thread_id=None), so the delivery posts flat — and the shipped origin-mirror then seeds the (slack, chat_id, None) shared-channel session, the exact bucket reply_in_thread: false already routes inbound channel replies to. A plain channel reply resolves to that session with the brief in context. No new seed code — it reuses the existing mirror.

This is model B (shared-channel session), deliberately not anchoring the seed to the delivery message's ts: on Slack, replying to a specific message is threading, so a ts anchor would only relocate the thread to first-reply-time, never deliver true threadless-continuable.

Config (the pairing)

# ~/.hermes/config.yaml
slack:
  cron_continuable_surface: in_channel   # default: thread
  reply_in_thread: false                 # required: answer + key the reply flat
  require_mention: false                 # so a plain reply continues the job

• reply_in_thread: false is required so the reply is answered flat and keyed to the seeded channel session. Missing it fails SAFE — you get a threaded continuation (≈ today), never a dropped reply — and the gateway logs a warning at startup (warn, not hard-reject: the two knobs stay orthogonal).
• require_mention: false (or a free-response channel) lets a plain reply continue the job; otherwise you'd have to @-mention on each reply. (Long-standing orthogonal channel knob — surfaced in docs.)
• Because the continuation is the whole-channel session, it's shared (other chatter joins the rolling conversation) — the same tradeoff reply_in_thread: false users already accept. Use the default thread surface when you want each delivery isolated.

Generic key, Slack first consumer

The scheduler reads the key generically from platform config; the in_channel branch is gated on a base-adapter capability flag supports_inchannel_continuable (Slack = True). Any platform without an implementation fails safe to thread with a debug log — no Slack-only special-case in core.

Files

• gateway/platforms/base.py — supports_inchannel_continuable capability flag (default False).
• plugins/platforms/slack/adapter.py — flag True; _cron_continuable_surface() resolver; _warn_if_inchannel_without_flat_reply() connect-time warning.
• gateway/config.py — shared-key bridge line (top-level or nested config).
• cron/scheduler.py — resolve the surface generically, gate the in_channel branch on the capability flag, skip thread-open.
• Docs: cron.md + slack.md (+ zh-Hans mirrors of both).

Testing

Run from inside the worktree (PYTHONPATH=$PWD):

• +6 cron scheduler tests — in_channel skips thread-open; seeds the flat channel session with thread_id=None; thread-mode regression; fail-safe on an unsupported platform; value coercion.
• Prove-fail — removing the and not in_channel_surface guard turns the two load-bearing tests RED; restore → GREEN.
• +10 slack resolver/capability/warning tests; +2 config-bridge tests.
• Offline E2E (tests/manual/cron_inchannel_e2e.py) — drives both real legs (delivery seed + inbound reply keying) and asserts they converge on (slack, C, None).
• No regressions: test_slack.py 216 passed alone; broader sweep green. (4 pre-existing cross-file-ordering failures in test_slack.py reproduce identically on pristine origin/main.)

Deploy note

Gateway-side config flag — a /restart picks it up. No Slack app reinstall needed (contrast a manifest/scope change).

Infographic

---

Mirror-of: NousResearch#56096
NousResearch#56096

[tenki-reviewer]

Review Complete
No issues found!

Risk: 🟢 Low (18/100) — no findings · 738 LOC across 12 files

---

No issues found meeting confidence and severity thresholds. PR adds cron in-channel delivery for Slack with proper config gating and fail-safe fallbacks.

Files Reviewed (12 files)

cron/scheduler.py
gateway/config.py
gateway/platforms/base.py
plugins/platforms/slack/adapter.py
tests/cron/test_scheduler.py
tests/gateway/test_slack_cron_continuable_surface.py
tests/gateway/test_slack_mention.py
tests/manual/cron_inchannel_e2e.py
website/docs/user-guide/features/cron.md
website/docs/user-guide/messaging/slack.md
website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/features/cron.md
website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/messaging/slack.md