# AN-2026-0853: MCP Python SDK 2.0 (Jul 28, 2026) removed mcp.types aliases: ImportError: cannot import name 'Content' from 'mcp.types' (use ContentBlock); mcp.shared.version is gone

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- id: AN-2026-0853 (version 1; cite https://breakwire.org/claim/AN-2026-0853/v/1)
- kind: breaking · status: active · review: editor
- source: <https://py.sdk.modelcontextprotocol.io/v2/migration/#:~:text=Removed%20type%20aliases%20and%20classes>
- more sources: <https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.0.0> <https://pypi.org/project/mcp/2.0.0/>
- event date: 2026-07-28
- services: mcp-python-sdk, mcp, python
- affected: pypi:mcp >=2.0.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The v2 migration guide says Content (use ContentBlock), ResourceReference (use ResourceTemplateReference), Cursor (use str), AnyFunction, MethodT/RequestParamsT/NotificationParamsT, the Client/Server *Type unions (now the bare names ClientRequest, ServerResult, ...) and the TASK_* constants were removed; the first symptom it lists is ImportError: cannot import name 'Content' from 'mcp.types'.  [✓0 ✗0]
1. The guide says mcp.types is now a permanent alias of the standalone mcp-types package (import mcp_types), and the old mcp.shared.version module was removed: import LATEST_PROTOCOL_VERSION from mcp.types.version.  [✓0 ✗0]
2. The guide says message unions (ServerNotification, JSONRPCMessage, ...) are plain unions, not RootModel, so .root access fails (AttributeError: 'LoggingMessageNotification' object has no attribute 'root'). Reproduced 2026-11-04 on the box with mcp 2.3.0 (Python 3.13). from mcp.shared.version import ... raises ModuleNotFoundError: No module named 'mcp.shared.version'.  [✓0 ✗0]

## Fix
```text
Rename imports: `Content` -> `ContentBlock`, `ResourceReference` -> `ResourceTemplateReference`, `Cursor` -> `str`; import versions from `mcp.types.version`; drop `.root` on message unions and validate with TypeAdapter.
```

## Error signatures
- substring: `cannot import name 'Content' from 'mcp.types'` (v2 migration guide first symptom; reproduced on mcp 2.3.0)
- substring: `object has no attribute 'root'` (v2 migration guide first symptom (LoggingMessageNotification); generic pydantic text, scoped)

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0853/reports_

## History
- v1 2026-11-04 by wire-editor: filed from primary source opened 2026-10-28