feat: add library-based ts-to-zod schema generation

[ochafik]

Summary

Add auto-generated Zod schemas and types from spec.types.ts using ts-to-zod, with pre-processing to match SDK type hierarchy.

Pipeline

spec.types.ts (from spec repo)
    ↓ preProcessTypes()
sdk.types.ts (SDK-compatible types)
    ↓ ts-to-zod
sdk.schemas.ts (generated Zod schemas)
    ↓
generated/index.ts (public API)
    ↓
types.ts (re-exports + SDK extras)

Pre-Processing (NEW)

Instead of post-processing generated schemas, we now pre-process the types:

content = content.replace(/extends JSONRPCRequest/g, 'extends Request');
content = content.replace(/extends JSONRPCNotification/g, 'extends Notification');

This transforms the type hierarchy so generated types/schemas match SDK conventions, where jsonrpc/id fields are handled at the transport layer.

Generated Files

• sdk.types.ts - Pre-processed types (SDK hierarchy)
• sdk.schemas.ts - Zod schemas from sdk.types.ts
• sdk.schemas.zod.test.ts - Integration tests
• index.ts - Public API with explicit exports

Post-Processing

Step	Transformation
1	Zod v4 import: "zod" → "zod/v4"
2	Index signatures: z.record().and(z.object()) → z.looseObject()
3	typeof expressions: jsonrpc: z.any() → z.literal("2.0")
4	Integer refinements: ProgressTokenSchema, RequestIdSchema use .int()

Usage

import { ProgressTokenSchema, ProgressToken } from '@modelcontextprotocol/sdk/generated';

What's Next

With sdk.types.ts now generated, types.ts can become a thin re-export layer:

// types.ts
export * from './generated/sdk.schemas.js';
export type * from './generated/sdk.types.js';
// + SDK-specific extras (ErrorCode, McpError, etc.)

Test plan

• npm run generate:schemas produces sdk.types.ts + sdk.schemas.ts
• npm run build succeeds
• 97 comparison tests pass (generated vs manual schemas)
• 1586 total tests pass (same pre-existing failures on main)

🤖 Generated with Claude Code

[pkg-pr-new]

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npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/sdk@1292

commit: 4d2ab8c