deps: migrate to mcp 2.x (lift the <2 pin) (#6)

Co-authored-by: claude <[email protected]>

docs_mcp/server.py

@@ -22,9 +22,10 @@ import logging
 import os
 import re
 from pathlib import Path
-from typing import Annotated
+from typing import Annotated, Any
 
-from mcp.server.fastmcp import FastMCP
+from mcp.server.mcpserver import MCPServer
+from mcp.server.transport_security import TransportSecuritySettings
 from pydantic import Field
 
 from .usage import TimedCall
@@ -61,9 +62,9 @@ RRF_K = int(os.environ.get("RRF_K", "60"))
 
 
 # ---------------------------------------------------------------------------
-# FastMCP setup.
+# MCPServer setup.
 # ---------------------------------------------------------------------------
-mcp = FastMCP(f"{PRODUCT_NAME}-docs", stateless_http=True)
+mcp = MCPServer(f"{PRODUCT_NAME}-docs")
 
 
 # ---------------------------------------------------------------------------
@@ -719,12 +720,23 @@ def main() -> None:
 
     if args.transport == "stdio":
         mcp.run()
-    else:
-        mcp.settings.host = args.host
-        mcp.settings.port = args.port
-        if os.environ.get("MCP_DISABLE_DNS_REBINDING_PROTECTION") in {"1", "true", "yes"}:
-            mcp.settings.transport_security.enable_dns_rebinding_protection = False
-        mcp.run(transport=args.transport)
+        return
+
+    # mcp 2.x: transport options are run() kwargs, and `mcp.settings` is gone.
+    run_kwargs: dict[str, Any] = {"host": args.host, "port": args.port}
+    if args.transport == "streamable-http":
+        # Was a constructor arg under 1.x. Required in prod — see CLAUDE.md
+        # (without it, every Watchtower recreate is a 404 storm from clients
+        # holding stale session IDs).
+        run_kwargs["stateless_http"] = True
+    if os.environ.get("MCP_DISABLE_DNS_REBINDING_PROTECTION") in {"1", "true", "yes"}:
+        # Deployed as `chem-mcp:8080` on Drawbar's internal docker network
+        # and never published to a host port, so the Host header the rebind
+        # check rejects is the only one we ever see.
+        run_kwargs["transport_security"] = TransportSecuritySettings(
+            enable_dns_rebinding_protection=False,
+        )
+    mcp.run(transport=args.transport, **run_kwargs)
 
 
 if __name__ == "__main__":