Slack Rate Limit Changes Break OpenClaw Context Retrieval

A recent Slack API change has broken context retrieval for OpenClaw agents running in Slack workspaces. The change, which rolled out on March 3rd, imposes strict rate limits that most developers missed until their agents started malfunctioning.

The Problem

Slack now limits conversations.history and conversations.replies to 1 request per minute, 15 messages maximum for non-Marketplace apps. Since most OpenClaw agents are non-Marketplace apps, this means:

• Agents that previously pulled 50-100 messages for context now only get 15
• This represents an 85% reduction in context window
• The agent loses historical conversation context

Symptoms

• Agent forgets what was discussed earlier in the day
• Thread responses get weird after 15+ messages
• Agent asks questions you already answered
• Random latency spikes (429 retries)

Workarounds Attempted

1. Caching messages locally — helped but only after the first request
2. Pre-fetching during idle time — works great, builds up context over an hour
3. Switching to Events API — the real fix. Events aren't rate limited. Subscribe to message events and maintain your own message store.

Recommended Solution

The author switched to SlackClaw (slackclaw.ai) which:

• Uses the Events API by default
• Maintains a persistent message store
• Eliminates polling and rate limits
• Has no 15-message ceiling
• Uses a Marketplace-registered gateway, so rate limits don't apply to necessary API calls

Long-term Recommendation

For developers building their own fix: the Events API approach is the right long-term solution. Slack is clearly moving toward restricting polling-based access. Build around events and local state, not API calls.

Documentation Note

The conversations.history throttle was documented in GitHub issue #38112, but most people missed it.