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Box MCP Write Tools Appear in Schema but Return “Tool Not Found” at Runtime

  • August 28, 2026
  • 2 replies
  • 80 views

Hi everyone,

I’m testing the Box MCP Server with ChatGPT and have run into an issue specifically with write/update operations.

Read operations work normally. I can search folders, list folder contents, read file metadata, and retrieve file contents without any problem.

However, when I try to update an existing file, the MCP tool schema shows that tools such as upload_file_version and get_upload_url are available, but when ChatGPT actually invokes them, the runtime returns:

Tool upload_file_version not found

and

Tool get_upload_url not found

The affected file is a normal Markdown (.md) file in Box, and the authenticated user appears to have upload/edit permissions on the folder.

So the situation seems to be:

  • Box MCP connection/authentication works

  • Read tools work

  • The write/upload tools appear in the exposed tool list/schema

  • But those tools are not available at runtime

Has anyone encountered this behavior with the Box MCP Server?

Is there an additional Box MCP configuration, permission, feature flag, or server-side setting required to enable file-version uploads or overwrite/update operations?

I’d also be interested to know whether this is a known issue where a tool is advertised in the MCP schema but is not actually registered on the runtime side.

Thanks!

2 replies

I can independently reproduce the same issue with the Box connector in ChatGPT.

Environment:
- Box account: Individual
- ChatGPT Box connector: connected successfully
- ChatGPT connector permission setting: "Allow all actions"

The following write operations work correctly:
- upload_file — SUCCESS
- create_folder — SUCCESS
- create_file_comment — SUCCESS
- copy_file — SUCCESS

However, the following tools are exposed in the ChatGPT tool/schema definitions, but fail at runtime:

- upload_file_version
  MCP error -32602: Tool upload_file_version not found

- get_upload_url
  MCP error -32602: Tool get_upload_url not found

- update_file_properties
  MCP error -32602: Tool update_file_properties not found

I also tested additional existing-item mutation operations:

- update_folder_properties
  MCP error -32602: Tool update_folder_properties not found

- move_file
  MCP error -32602: Tool move_file not found

The test file itself reports these Box permissions:
- canUpload: true
- canRename: true
- canDelete: true
- canComment: true
- canShare: true

So this does not appear to be a general Box write-permission issue. Creating new files/folders, copying files, and adding comments all succeed. The failures are specifically occurring for multiple tools that modify existing Box items.

I also performed a comparison using the Box connector in Claude. In Claude, upload_file_version, get_upload_url, and update_file_properties are not exposed in the connector schema at all, while upload_file works successfully.

So the behavior differs between clients:

- ChatGPT: these tools are exposed in the schema, but return "Tool not found" at runtime.
- Claude: the same tools are not exposed in the schema.

This makes me suspect there may be a mismatch between the tool catalog/schema exposed to the client and the tools actually registered or available at runtime.

Could someone from Box please confirm:

1. Whether upload_file_version, get_upload_url, update_file_properties, update_folder_properties, and move_file are currently expected to work with the ChatGPT Box connector for Individual accounts.
2. Whether there is any known issue with the MCP tool registry/tool exposure for these write tools.
3. Whether this behavior depends on Box plan, Tool Access configuration, or the specific AI client.

I am happy to provide additional reproduction details if needed.

  • jambus
  • New Member
  • September 16, 2026

I can reproduce the issue described in this thread with the Box connector in ChatGPT.

My workflow is to retrieve a PDF attachment from Microsoft Outlook and archive it in a specific Box folder. The Outlook connector successfully retrieves the attachment, and the Box connector can:

  • Search for folders and files

  • List folder contents

  • Read file and folder metadata

  • Create a new folder

However, uploading the PDF requires the get_upload_url tool. Although this tool is exposed in the ChatGPT tool schema, every invocation returns:

MCP error -32602: Tool get_upload_url not found

The affected file is a normal two-page PDF of approximately 49 KB. I retried the operation several times on September 16, 2026, fetched a fresh copy of the Outlook attachment, and confirmed that the destination folder exists and is empty. The result remained unchanged.

This does not appear to be related to the file size, file type, Box connection, or general write permissions, because folder creation works correctly. The failure seems limited to the binary-upload tool advertised in the schema but unavailable at runtime.

Could Box please confirm:

  1. Whether get_upload_url is currently supported by the Box connector in ChatGPT.

  2. Whether this is a known mismatch between the exposed tool schema and the tools registered at runtime.

  3. Whether there is a supported workaround for uploading binary files such as PDFs.

  4. Whether and when a fix is expected.

At present, this issue prevents automated archiving of Outlook PDF attachments in Box, even though all preceding workflow steps work correctly.

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