Hermes Agent A2A

What Hermes Agent A2A does

Hermes Agent A2A implemented the Google Agent2Agent protocol for Hermes by hand, from May to August 2026. It ran a local A2A server and offered tools to discover agents by registry name or URL, announce an agent to a shared registry, send JSON-RPC protocol tasks and poll them, run local or remote Hermes workers, relay messages into a live Hermes session, and read plugin metrics. It also supported SSE streaming, HMAC-signed push notifications and Telegram session routing.

The README opens with a deprecation notice. Hermes Agent v0.20.0 and later ship native A2A as the bundled a2a-platform plugin with a2a_discover, a2a_call, a2a_list, a2a_history and a2a_orchestrate, enabled through the a2a: section of the Hermes config. Fleet session relay moved to hermes-mesh and its mesh_send tool. The repository is archived, security fixes land upstream in Hermes, and the source remains for reference only.

Key features

• Agent discovery and registry announcement through a2a_discover and a2a_announce
• JSON-RPC protocol tasks with polling through a2a_send_protocol_task
• Local and remote ephemeral Hermes worker tasks
• HMAC-signed push notifications and SSE streaming
• Session relay into a target Hermes gateway session
• Plugin metrics through a2a_get_metrics

When to use it

• Reading how A2A was implemented as a Hermes plugin before native support existed
• Planning a migration from this plugin to the native a2a-platform plugin
• Understanding the old fleet session-relay design

Who it is for: Hermes users still running this plugin who need to migrate, and developers studying A2A plugin design.

How it fits with Hermes Agent

Built as a Hermes Agent plugin for Hermes fleet agents. It has been superseded by the native a2a-platform plugin that ships with Hermes Agent v0.20.0 and later.

Note: The repository is archived and deprecated since 2026-08-04, replaced by the native a2a-platform plugin in Hermes Agent v0.20.0 and later.

FAQ