Experiment for v6-beta: remove commonJS and zod 3

[gr2m]

Related to #9287

removing zod 3 lets us zod 4 mini which should help with bundle size and potentially benchmarks

[chentsulin]

Is it possible to keep Zod v3 support until the official TypeScript MCP SDK supports Zod v4?
ref:

• feat: zod v4 modelcontextprotocol/typescript-sdk#869
• Zod 4 supported modelcontextprotocol/typescript-sdk#555
• SDK V2 modelcontextprotocol/typescript-sdk#809
• feat: zod v4 with backwards compatibility for v3.25+ modelcontextprotocol/typescript-sdk#1040

This would allow more flexibility for internal tool development.

[gr2m]

This would only go into the v6 beta and we consider it an experiment to see what friction it might cause that we didn't anticipate.

@chentsulin do you have a feel how long it will take for @modelcontxtprotocol to update to Zod v4?

FYI @aayush-kapoor who is working on MCP

[chentsulin]

@gr2m From modelcontextprotocol/typescript-sdk#1040, it’s clear that compatibility work for Zod v4 is still progressing recently. However, I think it’s difficult to estimate how long it will take, or whether the change will need to be released together with MCP TypeScript SDK v2 (since it’s unclear if there are other blockers).