Claude Code: Notion MCP create-database fails with MCP error -32602 invalid arguments
Claude Code with the Notion MCP server (makenotion/notion-mcp-server) works for some Notion operations but fails when creating database entries: Claude retries many times and the server returns "MCP error -32602: Invalid arguments for tool create-database" with the required "properties" parameter reported as undefined. Other MCP servers work fine, so is this a known issue with Notion MCP or something on my end? Client: Claude Code (also affects Claude Desktop); tool version and OS were not specified in the thread.
Originally asked on GitHub: https://github.com/makenotion/notion-mcp-server/issues/74
6 answers
This is a known bug on the Anthropic/Claude side of the integration, not a configuration problem on your end. The issue was closed as completed: on July 22, 2025, a Notion MCP maintainer said Anthropic's fix had landed the previous week and worked for them in Claude Desktop. Notion's MCP beta overview acknowledged that most operations returned "invalid argument" errors because tools received an incorrect parameter shape, and that Anthropic had been informed and was investigating.
The failure signature others reported:
mcp.shared.exceptions.McpError: MCP error -32602: Invalid arguments for tool create-database "expected": "object", "received": "undefined", "path": ["properties"], "message": "Required"While the bug was active, Notion recommended trying Notion MCP with Cursor or ChatGPT instead (they also warned about excessive context token consumption). After the fix landed, one user reported it was still spotty: 2 of 5 identical test runs failed.
General advice: since the bug was a client-side tool-argument shape problem, keep your Claude client updated and, if failures persist, try a different LLM model as the maintainer suggested. No versions were given in the thread, so test with your current client before changing anything.
Did this work for you?What @mquan tried on GitHub (Worked)
A Notion collaborator explained that Anthropic's fix had landed the previous week, said it worked in Claude Desktop for them, and suggested using a different LLM model or redirecting the question to Claude if issues remain.
Did this work for you?What @tienttn-imt tried on GitHub (Partly worked)
A user re-ran five identical test runs after the fix and two still failed, so the behavior remained inconsistent.
Did this work for you?What @Z-Gort tried on GitHub (Outcome unclear)
Reported the exact server rejection for the create-database tool (error -32602, properties required but undefined). This confirmed the request was rejected for a wrong argument shape rather than an auth or permission problem.
Did this work for you?What @Kl-11 tried on GitHub (Didn't work)
The reporter tried repeatedly to create database entries through Notion MCP in Claude Code; the plain Notion API worked, and other Notion MCP calls worked, but database entry creation kept failing.
Source: https://github.com/makenotion/notion-mcp-server/issues/74 (opens external site)
Did this work for you?What @timothy-tt tried on GitHub (Outcome unclear)
Notion publicly acknowledged the issue and recommended trying Notion MCP with other agent tools such as Cursor or ChatGPT while the fix was pending.
Did this work for you?