Write actions blocked on custom MCP server – Business plan workspace, Developer Mode unavailable at workspace level

Thanks for the responses so far. I wanted to share additional findings that narrow this down considerably.

We have two versions of the same MCP server, with identical tool definitions:

• Production server: https://mcp.your-domain.com/internal/mcp → write actions are BLOCKED
• QA/testing server: https://mcp.your-domain-qa.net/platform02-core/mcp → write actions work SUCCESSFULLY

The only difference between them is the domain (.com vs .net). This strongly suggests the safety layer is evaluating the server’s domain as part of its decision to block write actions.

We tested two types of write actions to confirm this:

1. Creating a new email from scratch
   • Production: blocked, no request for writing tools reached our server
   • QA: succeeded, edit link returned correctly
2. Copying an existing email (simplest possible write action — no content, no parameters, just a copy)
   • Production: blocked
   • QA: succeeded, edit link returned correctly

The simple copy test is particularly relevant because it removes any possible variable related to content, URLs, or parameters. The only remaining variable is the server domain.

What we already tried:

• Marked the tools as non-destructive in the tool definition (destructiveHint: false)
• Simplified the tool call to its bare minimum (only library name and email name, no optional parameters)
• Tried a plain copy with no extra parameters whatsoever
• Verified server logs: no incoming request is registered when the call is blocked, confirming it never reaches our server

So my main question is: does anyone know why write actions are blocked specifically on the .com server while the equivalent .net one works fine? Any explanation would be super helpful.

Thanks again for your help.