Fix Incoming: Your OpenClaw Slack Agent Will Finally Remember Thread Context

If you've ever used OpenClaw with Slack, you've probably run into this frustrating scenario: you start a thread with your agent, it responds perfectly, then you follow up... and it has completely forgotten the conversation you're in.

The Problem

When OpenClaw handles Slack threads today, it only fetches thread history on the first message of a thread session. Every subsequent message in that thread? The agent receives it with zero context about what was said before.

This means your agent can't:

• Follow up on previous points in the thread
• Reference earlier context you provided
• Maintain coherent multi-turn conversations in threads

The culprit is a single conditional check that gates history fetching to only the initial turn:

if (threadInitialHistoryLimit > 0 && !threadSessionPreviousTimestamp) {

That !threadSessionPreviousTimestamp condition means "only if we haven't seen this thread before" — so subsequent turns skip history entirely.

The Fix: Delta Fetching

PR #16186 by @markshields-tl introduces a smart solution: delta fetching.

Instead of fetching the entire thread history every time (expensive and potentially hitting API limits), the fix:

1. Removes the first-turn gate — now history is fetched on every turn when threadInitialHistoryLimit > 0
2. Fetches only new messages — passes the session's last-seen timestamp as the oldest parameter to Slack's conversations.replies API
3. Exposes thread metadata — adds thread_ts, message_ts, channel_id, and is_thread_reply to the agent's inbound context

This means your agent gets exactly the context it needs — no more, no less — on every single turn.

Why Thread Metadata Matters

The PR also solves a secondary problem: agents had no way to know they were in a thread without hardcoded values.

Now the inbound metadata includes:

• thread_ts — The Slack thread timestamp (tells the agent which thread it's in)
• message_ts — The current message timestamp
• channel_id — The raw Slack channel/conversation ID
• is_thread_reply — A boolean flag for easy conditional logic

This enables agents to dynamically call tools like slack_thread_context without needing hardcoded channel IDs.

Impact for Slack Power Users

If you run an OpenClaw agent in Slack for team support, internal tools, or async collaboration, this fix changes the game:

• Multi-turn workflows work — Ask a question, get an answer, follow up naturally
• Parallel threads stay isolated — Five threads, five separate contexts, no bleeding
• Thread-aware tools become possible — Agents can now reference their thread context programmatically

How to Help

This PR is currently open and in review. If thread context bugs have bitten you:

1. Test the branch — Try it against your Slack setup and report results
2. Comment on the PR — Share your use case or edge cases you'd want tested
3. 👍 the PR — Signal to maintainers this matters to users

PR link: github.com/openclaw/openclaw/pull/16186

Related issues: #12742, #12586