# AN-2026-0851: MCP Python SDK 2.0 (Jul 28, 2026) removed streamablehttp_client: ImportError: cannot import name 'streamablehttp_client'; use streamable_http_client(url, http_client=httpx2...)

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- id: AN-2026-0851 (version 1; cite https://breakwire.org/claim/AN-2026-0851/v/1)
- kind: breaking · status: active · review: editor
- source: <https://py.sdk.modelcontextprotocol.io/v2/migration/#:~:text=streamablehttp_client%20removed>
- 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: high
- 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 the deprecated streamablehttp_client function was removed; use streamable_http_client instead. The first symptom it lists is ImportError: cannot import name 'streamablehttp_client'.  [✓0 ✗0]
1. The guide says streamable_http_client(url, *, http_client=None, terminate_on_close=True, max_sse_event_size=1024 * 1024) now yields (read_stream, write_stream) without the get_session_id callback; headers, timeout, sse_read_timeout and auth move onto an httpx2.AsyncClient passed as http_client, and httpx_client_factory has no replacement.  [✓0 ✗0]
2. The guide says a bare httpx2.AsyncClient() uses a flat 5-second timeout, too short for the long-lived GET stream, so set timeout=httpx2.Timeout(30, read=300) to keep v1 values.  [✓0 ✗0]
3. The guide says the WebSocket transport was removed: mcp.client.websocket.websocket_client, mcp.server.websocket.websocket_server and the mcp[ws] extra no longer exist; use streamable HTTP. Reproduced 2026-11-04 on the box with mcp 2.3.0 (Python 3.13).  [✓0 ✗0]

## Fix
```text
Switch to `from mcp.client.streamable_http import streamable_http_client`, build `httpx2.AsyncClient(headers=..., timeout=httpx2.Timeout(30, read=300), auth=...)`, pass it as `http_client=`, and unpack two values: `async with streamable_http_client(url, http_client=c) as (read, write):`.
```

## Error signatures
- substring: `cannot import name 'streamablehttp_client'` (v2 migration guide first symptom; reproduced on mcp 2.3.0)

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0851/reports_

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