Is your feature request related to a problem? Please describe.
In Inspector v2, input parameters can no longer be marked as nullable. This was supported in Inspector v1 and allowed testing MCP tools that intentionally accept null values for optional inputs. The removal of this capability makes it impossible to accurately test servers whose schemas rely on nullable input parameters.
Describe the solution you’d like
Reintroduce support for nullable input parameters in the Inspector. Ideally, the UI should allow users to explicitly set a parameter to null (instead of omitting it) when the schema allows nullable values.
Describe alternatives you’ve considered
The only current workaround is to modify the tool schema or server implementation to avoid nullable parameters, which is not desirable because it changes the API solely to accommodate the Inspector’s limitations. Another option is to manually invoke the server without the Inspector, but this defeats the purpose of having an interactive testing tool.
Additional context
This functionality was available in Inspector v1 and is required for testing existing MCP servers that use nullable input parameters. Restoring this behavior would improve backwards compatibility and make it easier to test schemas that legitimately distinguish between an omitted value and an explicit null.
Is your feature request related to a problem? Please describe.
In Inspector v2, input parameters can no longer be marked as nullable. This was supported in Inspector v1 and allowed testing MCP tools that intentionally accept null values for optional inputs. The removal of this capability makes it impossible to accurately test servers whose schemas rely on nullable input parameters.
Describe the solution you’d like
Reintroduce support for nullable input parameters in the Inspector. Ideally, the UI should allow users to explicitly set a parameter to null (instead of omitting it) when the schema allows nullable values.
Describe alternatives you’ve considered
The only current workaround is to modify the tool schema or server implementation to avoid nullable parameters, which is not desirable because it changes the API solely to accommodate the Inspector’s limitations. Another option is to manually invoke the server without the Inspector, but this defeats the purpose of having an interactive testing tool.
Additional context
This functionality was available in Inspector v1 and is required for testing existing MCP servers that use nullable input parameters. Restoring this behavior would improve backwards compatibility and make it easier to test schemas that legitimately distinguish between an omitted value and an explicit null.