# Model Context Protocol Python SDK (mcp) - AgentBreakWatch Reference

> TL;DR Verdict: Model Context Protocol Python SDK (`mcp`) is currently at v2.3.0 on PYPI (published 2026-10-02), with a 90-day Stability Score of 78/100 (B) and HIGH schema drift risk across 9 releases in the last 90 days. v2.x restructures FastMCP lifespan context, StreamableHTTP session handling, and CallToolResult structuredContent validation.

## Live Telemetry Metadata
- Canonical Page: https://agentbreakwatch.vercel.app/p/mcp-python
- Category Hub: https://agentbreakwatch.vercel.app/c/agent-sdks (AI Agent SDKs & Frameworks Breaking-Change Index)
- Package Name: `mcp`
- Registry: PYPI (https://pypi.org/project/mcp/)
- GitHub Repository: https://github.com/modelcontextprotocol/python-sdk
- Vendor: Model Context Protocol
- Latest Live Version: v2.3.0
- Published Date: 2026-10-02T22:06:52.119073Z
- 90-Day Release Count: 9
- Direct Dependencies: 19
- License: MIT
- Stability Score: 78/100 (Grade B)
- Schema Drift Risk: HIGH
- Recommended Exact Pin Command: `pip install "mcp==2.3.0"`
- Watched Symbols / MCP Tools: FastMCP, ClientSession, streamablehttp_client, CallToolResult
- Snapshot Timestamp: 2026-10-24T12:11:27.697Z

## Breaking Change & Schema Drift Summary
v2.x restructures FastMCP lifespan context, StreamableHTTP session handling, and CallToolResult structuredContent validation.

## Migration Diff: Before (Deprecated / Unpinned Pattern)
```
from mcp.client.sse import sse_client
async with sse_client("http://localhost:8000/sse") as (read, write):
    async with ClientSession(read, write) as session:
        await session.initialize()
```

## Migration Diff: After (Verified v2.3.0 Pattern)
```
from mcp.client.streamable_http import streamablehttp_client
async with streamablehttp_client("http://localhost:8000/mcp") as (read, write, _):
    async with ClientSession(read, write) as session:
        await session.initialize()
```

## Recent Verified Releases
- v2.3.0 (published 2026-10-02) [LATEST]
- v2.2.0 (published 2026-09-07)
- v1.30.0 (published 2026-09-07)
- v2.0.1 (published 2026-08-26)
- v2.1.1 (published 2026-08-25)
- v2.1.0 (published 2026-08-24)