codex - 💡(How to fix) Fix MCP tools registered and enabled but all return 'unsupported call' on invocation (v0.133.0)

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All MCP tools are registered, enabled, and visible in both codex mcp list and codex doctor, but every invocation returns unsupported call.

Root Cause

All MCP tools are registered, enabled, and visible in both codex mcp list and codex doctor, but every invocation returns unsupported call.

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Description

All MCP tools are registered, enabled, and visible in both codex mcp list and codex doctor, but every invocation returns unsupported call.

Environment

  • Codex Desktop version: v0.133.0
  • OS: macOS (Mac16,13 / MacBook Air)
  • Shell: bash

Steps to Reproduce

  1. Configure one or more MCP servers in Codex settings
  2. Run codex mcp list — all servers show as enabled
  3. Run codex doctor — no MCP-related errors reported
  4. In a Codex session, invoke any MCP tool (e.g. list_chats from a Feishu/Lark MCP server)
  5. The tool call returns: unsupported call: <tool_name>

Expected Behavior

MCP tools should execute normally when the server is enabled and healthy.

Actual Behavior

Every MCP tool call returns unsupported call regardless of server or tool type.

Additional Context

  • Multiple MCP servers tested (Feishu/Lark FastMCP server); all exhibit the same behavior
  • The MCP servers themselves are running and accessible outside of Codex
  • Issue persists after fully quitting and restarting Codex Desktop (Cmd+Q + reopen)
  • This blocks all MCP-dependent workflows

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codex - 💡(How to fix) Fix MCP tools registered and enabled but all return 'unsupported call' on invocation (v0.133.0)