# modelcontextprotocol/python-sdk · RepoSense Release & Migration Intelligence

> It was `>=2.5.0`. The new `max_sse_event_size` option n. Drop-in upgrade. Migration: None.

## Metadata
- **Repository URL**: https://github.com/modelcontextprotocol/python-sdk
- **Primary Package**: `mcp` (NPM)
- **Categories**: `AI-AGENT`, `AI-SDK`, `BACKEND`
- **Latest Version**: `v2.3.0`
- **Semantic Status**: `COMPATIBLE`
- **Bundle Size Impact (unavailable)**: `Size Unavailable`
- **Atom Ingestion Feed**: https://github.com/modelcontextprotocol/python-sdk/releases.atom

## The Human Context (Plain-English Pitch)
mcp is an open-source library and developer tool in the modelcontextprotocol/python-sdk ecosystem. It removes the friction of wiring up raw HTTP requests, streaming parsers, and authentication boilerplate so developers can integrate AI capabilities in a few lines of code.

## Stage 1 Executive Summary ([Core Change] + [Required Action] + [Migration Effort])
It was `>=2.5.0`. The new `max_sse_event_size` option n. Drop-in upgrade. Migration: None.

## Breaking Changes & Required Actions
- It was `>=2.5.0`. The new `max_sse_event_size` option needs it.
- Nothing to do unless you pin `httpx2` below 2.10.
- `@mcp.tool()`, `add_tool` and `Tool.from_function` raise `InvalidSignature`, naming the tool and the problem.
- Until now the server started, and 2026-07-28 clients silently dropped the tool from their listing.

## Migration Snippet
```ts
npm install mcp@2.3.0
```

## Ecosystem Compatibility Matrix & Graph Warnings
- **TypeScript 5.x** [`COMPATIBLE`]: Ships standard TypeScript declaration files without type regressions.

## Zero-Noise Release Timeline
- **v2.3.0** (2026-10-02) [COMPATIBLE]: It was `>=2.5.0`. The new `max_sse_event_size` option n. Drop-in upgrade. Migration: None.

## Upgrade & Migration Q&A (GEO Direct Answers)
### Is modelcontextprotocol/python-sdk v2.3.0 safe to upgrade in production?
modelcontextprotocol/python-sdk v2.3.0 is classified as COMPATIBLE (MINOR release). It was `>=2.5.0`. The new `max_sse_event_size` option n. Drop-in upgrade. Migration: None.

### What breaking changes or compatibility risks exist in modelcontextprotocol/python-sdk v2.3.0?
No breaking API changes or peer dependency conflicts are recorded for modelcontextprotocol/python-sdk v2.3.0 in the RepoSense compatibility graph.

### What is the bundle size impact of mcp v2.3.0?
Measured bundle size telemetry is currently unavailable for mcp v2.3.0; verify build output locally before deploying.

### How do I upgrade mcp to v2.3.0?
Upgrade mcp to v2.3.0 by running "npm install mcp@2.3.0" and applying the migration steps: npm install mcp@2.3.0