Bring your A2A agents to Slack

Slack added support for acting as an A2A (Agent2Agent) client, so an agent you've already built on the A2A protocol can run inside Slack without any Slack-specific code.

You host the agent and publish its Agent Card, the public document that tells clients how to reach it and what it can do. Give Slack the Agent Card URL when you create and install the Slack app, and Slack calls your agent when people talk to it. There's no request URL to set up and no event handling to write.

In direct messages, the agent shows a progress indicator, offers suggested prompts, and can exchange files in both directions. When someone mentions it in a channel, the reply goes privately to the person who asked, and it becomes a regular Slack message only if they choose to share it. Slack holds that private reply for up to 30 minutes. Replies can stream, and long-running tasks can work in the background and return their results to the original thread.

Slack supports A2A protocol versions v0.3 and v1.0 over JSON-RPC and HTTP+JSON. Your agent can authenticate with OAuth 2.0, a static credential, or no authentication, declared on the Agent Card. The Agent Card has to be published at a public HTTPS URL.