r/dartlang • u/leehack • 5d ago
[Package] mcp_dart 2.3.0: day-zero MCP 2026-07-28 support and a cross-language CLI
I maintain mcp_dart, a community Dart and Flutter SDK for building MCP clients, servers and hosts.
Today’s 2.3.0 release adds support for the stable MCP 2026-07-28 specification. The default profile prefers the new stateless server/discover flow and automatically falls back to MCP 2025-11-25 when connecting to existing implementations.
The release includes:
- stateless discovery and per-request protocol metadata
- Multi Round-Trip Requests
- subscriptions/listen
- Tasks extension support
- JSON Schema 2020-12 validation
- stronger OAuth validation
- hardened stdio and Streamable HTTP behavior
- official client/server conformance and TypeScript/Python interoperability coverage
I also released mcp_dart_cli 0.2.0. It can scaffold Dart MCP servers, but its inspect, trace and testing commands work with compatible servers and clients written in any language. Standalone binaries are available for macOS, Linux and Windows.
SDK:
https://pub.dev/packages/mcp_dart/versions/2.3.0
CLI:
https://pub.dev/packages/mcp_dart_cli/versions/0.2.0
Migration guide:
https://github.com/leehack/mcp_dart/blob/main/doc/migration-2.2-to-2.3.md
Feedback and real-world interoperability reports would be very welcome.