claude-code - 💡(How to fix) Fix [BUG] Claude in Chrome MCP: tabId coerced from number to string in tool invocation layer, breaking navigate [1 comments, 2 participants]

Call: navigate with tabId: 785895690 (JSON number in the tool call):* MCP error -32602: Input validation error: Invalid arguments for tool navigate: [ { "code": "invalid_type", "expected": "number", "received": "string", "path": ["tabId"], "message": "Expected number, received string" } ]

For reference — tabs_context_mcp response (tabId is a number here): {"availableTabs":[{"tabId":785895690,"title":"New Tab","url":"chrome://newtab/"}],"tabGroupId":2063123329}

TL;DR

The issue can likely be fixed by modifying the tool invocation layer to pass numeric parameters as numbers instead of coercing them to strings before forwarding to the Chrome MCP server.

Guidance

• Verify that the tabId is indeed being coerced to a string by checking the request payload sent to the MCP server.
• Investigate the tool invocation layer code to identify where the type coercion is occurring and modify it to preserve the numeric type of the tabId parameter.
• Test the modified code by repeating the steps to reproduce the issue and checking if the tabId is received as a number by the MCP server.
• Consider adding type checks or validation in the tool invocation layer to ensure that numeric parameters are not coerced to strings.

Example

No code snippet can be provided without knowing the exact implementation of the tool invocation layer, but the fix would involve changing the way numeric parameters are handled, for example, by using a library that preserves the numeric type or by manually checking the type of the parameter before forwarding it.

Notes

The issue is specific to the interaction between the Claude model and the Chrome MCP server, and the fix would depend on the implementation details of the tool invocation layer. The provided information suggests that the issue is a regression, and the previous working version may have handled numeric parameters differently.

Recommendation

Apply a workaround by modifying the tool invocation layer to correctly handle numeric parameters, as the root cause of the issue is identified and a targeted fix can be implemented.