fix: use default import for zod/v4 to support Deno/esm.sh (#1182)

[tonxxd]

Changes import * as z from 'zod/v4' to import z from 'zod/v4' (namespace import to default import) across all files that use zod/v4 to fix compatibility with Deno environments using esm.sh.

This change fixes issue #1182 where the SDK causes a TypeError: e.custom is not a function when deployed to Deno environments (like Supabase Edge Functions) and loaded via esm.sh.
When esm.sh bundles the SDK for Deno, the zod/v4 module's named exports (z.custom, z.string, z.object, etc.) are not available on the namespace import. With import * as z, these functions become undefined. They only exist on z.default.

How Has This Been Tested?

• npm run typecheck
• Build succeeds
• Created and ran Deno test scripts to reproduce the issue and verify the fix

Breaking Changes

None

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

Impact:

• Fixes issue TypeError: e.custom is not a function in Deno environments (v1.23.0) #1182

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/sdk@1194 

commit: 794eeeb

[KKonstantinov]

LGTM

[KKonstantinov]

@modelcontextprotocol/typescript-sdk-auth - need approval on this one.

[mattzcarey]

I'm not sure how we keep this in sync in future