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A2A Agents

The A2A Agents integration lets you plug in any external agent that speaks the A2A (Agent-to-Agent) protocol and use it inside SimplAI as if it were a native SimplAI agent. Once connected, an external A2A agent can be attached as a sub-agent and participates in orchestration exactly like a SimplAI sub-agent.

Where it lives​

  • Open Connections.
  • Go to the A2A Agents tab. (This sits alongside the MCP tab and follows the same connection pattern.)
  • Click New to open the connection drawer.

Connect an A2A agent​

The connection drawer asks for:

  • Name — a label for the connection.
  • Description — what the agent does, to help others pick it later.
  • Base URL — the A2A endpoint of the external agent.
  • Auth Token — the credential used to authenticate calls. Stored encrypted.
  • Any additional fields the external agent requires.

On Connect, the A2A agent becomes available within the current project.

Project scoping​

A2A connections are project-scoped — a connection you create is usable only inside the project where it was added. To use the same external agent in another project, connect it again there. This mirrors how MCP connections behave.

Add from where you need it​

Besides the Connections screen, you can add a new A2A agent inline from:

  • Agents screen → Sub-agents panel — "Add new".
  • Tools / AI Chains screen → node picker — "Add new".

Use an A2A agent as a sub-agent​

This is the current primary use of A2A connections.

  • Open your agent in Studio.
  • In the Sub-Agents card, click Add.
  • In the Add sub-agents drawer, switch to the A2A (Connected A2A Agents) tab.
  • Select the connected A2A agent from the list and attach it.

Once attached, an A2A sub-agent behaves the same as a native sub-agent during orchestration: the parent agent's planner can delegate work to it, pass it a self-contained message, and interpret its result. For the full sub-agent runtime model and delegation rules, see Add Sub-Agents.

Roadmap​

The following are planned and may ship as the protocol support matures:

  • A2A agents as nodes in Tools / AI Chains — selectable in the node picker alongside Pre-built Steps, Tools, Agents, and MCP Tools. The A2A node would run like a SimplAI agent node, with the same inputs/outputs, error handling, and logs.
  • A2A agents as SimplAI Agents (on request) — so a connected A2A agent can be exposed through SimplAI's Embed Code & SDK.

Notes​

  • The A2A connection UX intentionally mirrors the existing MCP connection flow for familiarity.
  • Connections are usable only in the project where they were created.