---
title: "Unolia connector update: MCP 2026-07-28 and RFC 9728"
description: "The Unolia connector now follows MCP revision 2026-07-28: a stateless handshake, a tool list cacheable for five minutes, and real HTTP statuses on errors."
url: "https://unolia.com/blog/ai-connector-newest-agent-protocol"
locale: "en"
---

# The Unolia connector now speaks MCP 2026-07-28

The connector behind your AI agents follows the current protocol revision: no handshake to keep, a tool list your agent can cache, and errors that arrive as errors.

The Unolia connector now speaks revision 2026-07-28 of the Model Context Protocol, the current version of the language AI agents use to reach your projects. Existing connectors keep working, and three things changed.

## One call to discover the server

Revision 2026-07-28 made MCP stateless. The `initialize` handshake and the session id are gone, and every request now carries its own protocol version and client capabilities. An agent that wants to know what we support asks once with `server/discover`. Agents still on the old handshake get back the version they asked for, so nothing breaks.

## A tool list your agent can cache

List results now carry a freshness hint and a cache scope. Ours declares the tool list cacheable for five minutes, privately, because the tools an agent sees depend on what its token is allowed to do. Your agent stops re-reading the whole catalog at the start of every conversation.

## Errors that arrive as errors

A tool call your access does not cover now answers 400 instead of 200 with the error buried inside, an unknown method answers 404, and a request whose headers disagree with its body answers 400 with `-32020`. A misconfigured agent shows up instead of quietly retrying.

Sign-in is unchanged. The connector publishes its OAuth metadata per RFC 9728 and the 401 points a client straight at it, so nothing is configured by hand.

The connector updating to revision 2026-07-28, with the three changes that come with it.

MCP 2026-07-28

- One call replaces the initialize handshake
- The tool list caches for five minutes, privately
- Failed tool calls answer with a real HTTP status