Best possible solution:

Land the narrow reset-aware Slack reseeding fix after maintainer acceptance, while leaving broader rollover continuity to the separate family-history or carryover work.

Do we have a high-confidence way to reproduce the issue?

Yes. Current main is source-reproducible by creating an existing Slack thread row that is stale under the reset policy, then preparing a reply in that thread: Slack's timestamp gate skips history while session initialization would roll the row to a fresh session.

Is this the best way to solve the issue?

Yes. The latest head is the best narrow fix for this bug: it aligns Slack's initial thread-history gate with the same reset freshness semantics as session initialization, preserves the direct-monitor/fresh/zero-history cases, and avoids replaying archived transcripts.

AGENTS.md: found and applied where relevant.

Codex review notes: model internal, reasoning high; reviewed against 119dc4bd821e.

Label changes:

• add rating: 🐚 platinum hermit: Overall readiness is 🐚 platinum hermit; proof is 🦞 diamond lobster and patch quality is 🐚 platinum hermit.
• add status: 👀 ready for maintainer look: ClawSweeper has no concrete contributor-facing blocker left for this PR. Sufficient (live_output): Live Slack/API proof in the PR discussion demonstrates the central stale-thread reseeding path, and the later production follow-up only restores direct-monitor fallback while focused tests cover that caller shape.
• remove rating: 🧂 unranked krab: Current PR rating is rating: 🐚 platinum hermit, so this older rating label is no longer current.
• remove status: ⏳ waiting on author: Current PR status label is status: 👀 ready for maintainer look.

Label justifications:

• P2: This is a normal-priority Slack/session-context bug fix with concrete user impact but no core outage, security emergency, or release-blocker signal.
• merge-risk: 🚨 compatibility: Existing Slack users can see different first-turn prompt context after a daily or idle session rollover because stale rows now reseed bounded native thread history.
• merge-risk: 🚨 session-state: The PR changes how Slack prepare interprets persisted thread session freshness before session initialization rotates or reuses state.
• rating: 🐚 platinum hermit: Overall readiness is 🐚 platinum hermit; proof is 🦞 diamond lobster and patch quality is 🐚 platinum hermit.
• status: 👀 ready for maintainer look: ClawSweeper has no concrete contributor-facing blocker left for this PR. Sufficient (live_output): Live Slack/API proof in the PR discussion demonstrates the central stale-thread reseeding path, and the later production follow-up only restores direct-monitor fallback while focused tests cover that caller shape.
• proof: sufficient: Contributor real behavior proof is sufficient. Live Slack/API proof in the PR discussion demonstrates the central stale-thread reseeding path, and the later production follow-up only restores direct-monitor fallback while focused tests cover that caller shape.

PR surface:

Source +186, Tests +538, Docs 0, Generated 0, Other +3. Total +727 across 21 files.

What I checked:

• Live PR state: Live PR metadata shows this PR is open on head 1f8e6bf, uses closing syntax for Slack thread replies after daily reset should seed thread history #97073, is mergeable but unstable, and carries the protected maintainer plus compatibility/session-state risk labels. (1f8e6bf4f662)
• Current main Slack mismatch: Current main still gates Slack initial thread history on readSessionUpdatedAt, so any stored thread row is treated as existing before reset-policy freshness is considered. (extensions/slack/src/monitor/message-handler/prepare-thread-context.ts:128, 119dc4bd821e)
• Current main reset authority: Current main session initialization evaluates provider-owned implicit expiry, lifecycle timestamps, and reset policy separately, so the same row can roll to a new session after Slack prepare skipped initial history. (src/auto-reply/reply/session.ts:499, 119dc4bd821e)
• PR Slack fix path: The PR head resolves reset freshness through the channel runtime and treats missing or stale freshness as initial thread context while preserving the old timestamp fallback when no channel runtime is present. (extensions/slack/src/monitor/message-handler/prepare-thread-context.ts:164, 1f8e6bf4f662)
• PR session helper semantics: The new helper mirrors the session initializer's lifecycle-freshness rule, including provider-owned implicit reset behavior and explicit reset overrides. (src/config/sessions/entry-freshness.ts:53, 1f8e6bf4f662)
• Focused regression coverage: The PR head covers fresh existing-thread skip, omitted channel-runtime fallback, stale reset-history seeding, provider-owned implicit reset, and initialHistoryLimit: 0 behavior. (extensions/slack/src/monitor/message-handler/prepare.test.ts:1911, 1f8e6bf4f662)

Likely related people:

• sourman: PR metadata for fix(slack): reduce token bloat by skipping thread context on existing sessions #32133 shows sourman authored the merged Slack bloat-guard change that skipped thread context on existing sessions, the Slack-side gate this PR adjusts. (role: introduced related Slack history optimization; confidence: high; commits: 201aee6c7c58, 2438fde6d9ba; files: src/slack/monitor/message-handler/prepare.ts, src/slack/monitor/message-handler/prepare.test.ts, extensions/slack/src/monitor/message-handler/prepare-thread-context.ts)
• steipete: steipete merged PR 32133 and authored the daily reset policy history that defines the stale-session rollover behavior involved here. (role: merger and adjacent session lifecycle contributor; confidence: high; commits: 2438fde6d9ba, 367826f6e4e9; files: src/slack/monitor/message-handler/prepare.test.ts, src/auto-reply/reply/session.ts)
• vincentkoc: Vincent Koc isolated reset-policy helpers used by the freshness path and recently merged adjacent current-main session/runtime changes. (role: adjacent reset-policy contributor and merger; confidence: medium; commits: c70be4b4afd0, 5ccfc97b31e3; files: src/config/sessions/reset-policy.ts, src/config/sessions/reset.ts, extensions/slack/src/monitor/message-handler/prepare-thread-context.ts)
• Ayaan Zaidi: Ayaan Zaidi recently changed reply session initialization serialization on the same session initialization path that evaluates freshness and rolls stale entries. (role: recent session initialization contributor; confidence: medium; commits: d2da8c79d9b8; files: src/auto-reply/reply/session.ts, src/auto-reply/reply/session.test.ts)

• 🦀 challenger crab: rare, exceptional readiness with strong proof, clean implementation, and convincing validation.
• 🦞 diamond lobster: very strong readiness with only minor maintainer review expected.
• 🐚 platinum hermit: good normal PR, likely mergeable with ordinary maintainer review.
• 🦐 gold shrimp: useful signal, but proof or patch confidence is still limited.
• 🦪 silver shellfish: thin signal; proof, validation, or implementation needs work.
• 🧂 unranked krab: not merge-ready because proof is missing/unusable or there are serious correctness or safety concerns.
• 🌊 off-meta tidepool: rating does not apply to this item.

Shiny media proof means a screenshot, video, or linked artifact directly shows the changed behavior. Runtime, network, CSP, and security claims still need visible diagnostics.

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