Home / Fixes

Slack MCP search fails: needs keywords and natural_language_query

Error: Slack search tool rejects the call

What causes it

slack_search_channels needs both keywords and natural_language_query. Semantic search is unavailable on the free plan.

How to fix it

1. Pass both fields on every call.
2. Expect keyword-only behavior on a free Slack workspace.

Where we hit it

• Slack MCP test report (tested Oct 16, 2026). Setup: Claude, Claude Code, Cursor, VS Code, ChatGPT

Related fixes

• MCP error: "Incompatible auth server: does not support dynamic client registration"
• MCP error -32601 Method not found on resources/list

All MCP fixes | Setup guides | Hit a different error? Request a test