Why This Matters

When OpenClaw replies in Slack, threaded conversations keep parallel work streams organized — you can have five things going at once without messages bleeding together. But today, the agent loses thread context after the first message, so it can't follow the conversation it's in. Additionally, proactive heartbeat messages incorrectly thread into whatever conversation was last active. This PR fixes both gaps.

Problem (Technical)

1. Missing thread history on subsequent turns

When a user sends a 2nd+ message in a Slack thread, the agent receives no thread history context. Only the first message in a thread session fetches history.

Root Cause: prepare.ts line 508:

if (threadInitialHistoryLimit > 0 && !threadSessionPreviousTimestamp) {

The !threadSessionPreviousTimestamp condition means history is only fetched on the first turn.

2. Heartbeat messages threading into unrelated conversations

Proactive heartbeat/cron messages inherit the session's lastThreadId, causing them to reply in whatever thread was last active instead of going top-level.

Root Cause: resolveHeartbeatDeliveryTarget in targets.ts passes through resolvedTarget.threadId unconditionally, which falls back to session lastThreadId.

Fix

Delta fetch for thread history

• Remove the !threadSessionPreviousTimestamp gate — always fetch thread history when threadInitialHistoryLimit > 0
• Delta fetch — pass threadSessionPreviousTimestamp as the oldest parameter to Slack's conversations.replies API, so only messages newer than the last seen timestamp are fetched
• Add oldest param to resolveSlackThreadHistory to support the delta fetch

Expose thread context in inbound meta

• thread_ts — Slack thread timestamp, present when message is a thread reply
• message_ts — Slack message timestamp for the current message
• channel_id — Raw Slack channel/conversation ID (e.g. D0AD6FBJB3R)
• is_thread_reply flag in flags object
• ProviderChannelId in template context, passed from message.channel
• extractChannelId() helper that parses channel ID from GroupChannel, To, or raw value

Prevent heartbeat thread leaking

• resolveHeartbeatDeliveryTarget now only uses threadId when explicitly configured (e.g. Telegram :topic: syntax), not inherited from session history
• Proactive sends go top-level by default

Changes

• src/slack/monitor/message-handler/prepare.ts — remove first-turn gate, add delta fetch with oldest, pass ProviderChannelId
• src/slack/monitor/media.ts — add oldest param to resolveSlackThreadHistory
• src/auto-reply/templating.ts — add ThreadTs, ProviderChannelId to MsgContext type
• src/auto-reply/reply/inbound-meta.ts — add thread_ts, message_ts, channel_id, is_thread_reply to inbound meta JSON; add extractChannelId() helper
• src/infra/outbound/targets.ts — filter threadId in heartbeat delivery to explicit-only
• src/infra/heartbeat-runner.returns-default-unset.test.ts — regression test for heartbeat thread leaking
• prepare.inbound-contract.test.ts — update test to verify delta fetch behavior

Testing

All existing tests pass. New regression test added for heartbeat thread leaking. Validated against live Slack threads.

Fixes #12742, #12586

🤖 AI-Assisted Contribution

Built by Claude (via OpenClaw agent). Fully tested against live Slack threads — validated that delta fetch resolves the core problem of missing thread context on subsequent turns. The author understands the changes and the codebase context that motivated them.