NetSuite MCP connector (ns_updateRecord) fails with HTTP 400 when account default language is Portuguese

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?

The NetSuite MCP connector (ns_updateRecord) fails with HTTP 400
when the NetSuite account's default language is set to Portuguese ('pt').

Error:
"Invalid language. REST web services currently only support the default
company language, and do not support the language specified in your user
preferences. Provide the Content-Language header with your default company
language value 'pt'."

The connector is not sending the required Content-Language: pt header
in write requests (PUT/PATCH). Read operations (SuiteQL queries via
ns_runCustomSuiteQL) work correctly. Only write operations fail.

What Should Happen?

The connector should include the Content-Language: pt header in all
write requests (PUT/PATCH) to match the NetSuite account's default
language, allowing ns_updateRecord and ns_createRecord to work
correctly in non-English NetSuite accounts.

Error Messages/Logs

Error:
"Invalid language. REST web services currently only support the default 
company language, and do not support the language specified in your user 
preferences. Provide the Content-Language header with your default company 
language value 'pt'."

Steps to Reproduce

1. Connect Claude to a NetSuite account whose default language is Portuguese ('pt')
2. Call ns_updateRecord on any record type (e.g. account)
3. Observe HTTP 400 error with Content-Language header error

Claude Model

Not sure / Multiple models

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

1.2773.0

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

This issue occurs specifically with the NetSuite MCP connector integrated
in Claude Desktop. The connector authenticates with a NetSuite account
whose company default language is Portuguese ('pt').

The MCP tool ns_runCustomSuiteQL (read) works correctly.
The MCP tool ns_updateRecord (write) fails with HTTP 400 on every attempt.

The fix should be applied on the connector side: send
Content-Language: pt in the HTTP headers of all write requests to
the NetSuite REST API.

This affects any NetSuite account whose default language is not English.