Dropbox MCP server tool schema incompatible with Anthropic/Claude strict tool validation

ABM13

Hi Dropbox team,I’m using the official Dropbox MCP endpoint with Claude Cowork:https://mcp.dropbox.com/mcpThe OAuth connection works correctly. Claude can authenticate and the WhoAmI/account check succeeds.However, Dropbox file/folder operations fail with this error:API Error: 400{"type": "error","error": {"type": "invalid_request_error","message": "tools.8.custom.input_schema: input_schema does not support oneOf, allOf, or anyOf at the top level"},"request_id": "req_011CauXV8iqCAGC7BNt7YccS"}This appears to be a schema compatibility issue. One of the Dropbox MCP tools seems to expose an input_schema using oneOf, allOf, or anyOf at the root level, which Anthropic/Claude rejects under strict tool validation.Reinstalling or reconnecting does not help because OAuth works. Only the Dropbox file operation tools fail.Can the Dropbox MCP server tool schemas be updated so that no input_schema uses oneOf/allOf/anyOf at the top level?Expected behavior:- OAuth succeeds- WhoAmI/account check succeeds- File/folder tools such as listing folders and reading files should workActual behavior:- OAuth succeeds- WhoAmI succeeds- File/folder tools fail with the schema validation error aboveThanks.

iNeil

Hi ABM13, Thanks for reporting this. We were able to reproduce the issue with the Dropbox MCP list_folder tool in Anthropic Claude, and I’ve escalated it to our engineering team for further investigation. I’ll share an update here once I have more information.