feat: MCP v2 (draft)

[KKonstantinov]

Migrate @upstash/context7-mcp to MCP TypeScript SDK v2

Summary

This PR migrates the packages/mcp server (@upstash/context7-mcp) from the MCP
TypeScript SDK v1 (@modelcontextprotocol/sdk) to v2
(@modelcontextprotocol/server + @modelcontextprotocol/node).

It is a mechanical, behavior-preserving migration — no tool logic, prompts, transport
wiring, or runtime behavior changed. The bulk of it was produced by the official
@modelcontextprotocol/codemod and then reviewed by hand.

Why v2

v2 replaces the single monolithic @modelcontextprotocol/sdk package with a set of
focused, ESM-only packages:

• @modelcontextprotocol/server — the runtime-neutral server API (McpServer,
  stdio transport, shared types).
• @modelcontextprotocol/node — the Node.js HTTP transport
  (NodeStreamableHTTPServerTransport).

The result is a smaller dependency surface, a cleaner public API, and first-class
support for non-Node runtimes. v1 is being superseded, so new work should target v2.

What changed (high level)

Area	Before (v1)	After (v2)
Dependencies	@modelcontextprotocol/sdk	@modelcontextprotocol/server + @modelcontextprotocol/node
Imports	deep paths under @modelcontextprotocol/sdk/...	the two new packages
Tool input schemas	raw Zod shape { query: z.string() }	wrapped z.object({ query: z.string() })
Low-level handlers	setRequestHandler(ListPromptsRequestSchema, …)	setRequestHandler("prompts/list", …)
HTTP transport	StreamableHTTPServerTransport	NodeStreamableHTTPServerTransport

Two concrete illustrations:

// Tool schemas now use Standard Schema — raw shapes are wrapped in z.object()
inputSchema: z.object({
  query: z.string().describe("…"),
  libraryName: z.string().describe("…"),
}),

// Low-level handlers take a method string instead of a Zod request schema
server.server.setRequestHandler("prompts/list", async () => ({ prompts: [] }));
server.server.setRequestHandler("resources/list", async () => ({ resources: [] }));
server.server.setRequestHandler("resources/templates/list", async () => ({ resourceTemplates: [] }));

What did NOT change

• Tool names, descriptions, annotations, and arguments.
• The Express/Streamable-HTTP and stdio serving logic.
• Auth, JWT handling, session store, and API-call code.
• The zod dependency (already ^4.4.3; v2's Standard Schema requirement is satisfied
  by Zod v4).

How this was produced

Generated with the official MCP v1→v2 codemod and reviewed by hand:

npx @modelcontextprotocol/codemod packages/mcp/src

Verification

All package checks pass after the migration:

• ✅ typecheck (tsc --noEmit)
• ✅ build (tsc)
• ✅ test (vitest run) — 12/12 passing
• ✅ lint (eslint .)

Before merging

• v2 is currently pre-release (2.0.0-alpha.3). The dependency pins reflect that.
  Recommend merging once v2 reaches a stable release and re-pinning to the GA version.
• The minimumReleaseAgeExclude: ['@modelcontextprotocol/*'] entry added to
  pnpm-workspace.yaml exempts the SDK packages from this repo's 7-day
  minimumReleaseAge gate so the pre-release versions can be installed. It can be
  removed once the depended-on v2 release is older than that window.

Roadmap

• Initial alpha draft
• Update to beta (legacy era MCP on modern interfaces)
• Update to stable - backwards compatible with legacy era MCP clients; enabling Modern stateless MCP will need context7 maintainers support