[BUG] "parent" are double-stringified in Notion-MCP tool calls → server throws “Expected object, received string”
Status Fixed / completed
Maintainer reply ✓ Yes — ashwin-ant
Activity 9 comments · opened Jul 5, 2025 · closed Jul 18, 2025
💡 Likely answer: A maintainer (ashwin-ant, collaborator)
responded on this thread — see the highlighted reply below.
Environment
- Platform (select one):
- [ ] Anthropic API
- Claude CLI version: 1.0.43
- Operating System: Ubuntu 22.04
Bug Description
When Claudecode invokes any Notion-MCP tool (create-pages, update-page, move-pages, …), object-typed arguments—e.g. parent is JSON-stringified twice. The remote MCP server therefore receives a string instead of the expected object and rejects the request with a schema error.
Steps to Reproduce
- ask claude code to create a notion page under a certain page as child page using notion mcp
Expected Behavior
parent (and any other object fields) should be transmitted as a JSON object exactly as produced by the LLM, allowing the MCP server to validate and process the request.
9 Comments
or maybe this bug is due to notion mcp server beta (official).
I think I'm seeing the same (or similar) thing with Claude Desktop integrating with the Notion web connector and any MCP tool requiring object parameters (e.g. create-pages)
Are you seeing this with other MCP clients as well? For example the MCP inspector? https://github.com/modelcontextprotocol/inspector
In my case, I'm seeing it when using the Notion web connector in Claude Desktop but not when configuring the MCP server myself based on
@notionhq/notion-mcp-server. When configuring it myself, everything works as expected.<img width="656" height="665" alt="Image" src="https://github.com/user-attachments/assets/7045c06a-450f-43bb-8b88-7668e4573d91" />
i tried again and this bug is now already fixed! (claude-code version 1.0.53)
Can anyone else confirm that? We didn't make any change here, so it's possible this was an issue on Notion's side.
I tried my case (Claude Desktop 0.12.16) again today and I'm no longer seeing the issue either 🎉
Great, I'll close this out then.
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.