Meta Ads MCP returns 500 error on all tool calls after successful connection

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

After connecting the Meta Ads MCP and completing the full OAuth/Facebook authorization flow, all tool calls (e.g. ads_get_ad_accounts) immediately return a 500 error. The MCP shows as connected in settings but no tools function.

Steps to reproduce:

Add the Meta Ads MCP in Claude Code settings
Complete the Facebook OAuth authorization flow
Ask Claude to call any Meta Ads tool (e.g. list ad accounts)
Tool returns: Tool call failed: 500
Expected behavior: Tool should return a list of ad accounts.

Environment:

Claude Code version: (latest)
OS: macOS
Attempted reconnecting multiple times — issue persists

What Should Happen?

It should connect and be able to access ad accounts as described in the MCP layout.

Error Messages/Logs

Tool call failed: 500

Steps to Reproduce

Add the Meta Ads MCP in Claude Code settings
Complete the Facebook OAuth authorization flow
Ask Claude to call any Meta Ads tool (e.g. list ad accounts)
Tool returns: Tool call failed: 500
Expected behavior: Tool should return a list of ad accounts.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.59

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_