Hermes A2A Bridge

What Hermes A2A Bridge does

Hermes A2A Bridge is a thin, local-first bridge that let Hermes Agent call other agents and expose itself as one, using the Google A2A protocol over HTTP and JSON with text and structured data parts, SSE streaming and durable replay. The README calls it an A2A-shaped surface and says it does not claim full compliance. It installs as a Python package that registers a hermes_agent.plugins entry point named a2a-bridge, which is enabled by listing it under plugins.enabled in ~/.hermes/config.yaml.

The repository is archived and read-only. Hermes Agent now ships native A2A support as a gateway platform and an a2a toolset, which the README tells you to use instead. The built-in version adds outbound tools a2a_discover, a2a_call, a2a_history and a2a_orchestrate, plus an inbound Agent Card, JSON-RPC 2.0, SSE streaming and HMAC-signed push notifications, with per-peer tokens, prompt-injection filtering, an audit log and anti-loop turn caps. The last version listed is v0.5.0, which needs Python 3.11 or newer.

Key features

• Outbound calls to other A2A agents from Hermes
• Hermes exposed as an A2A agent with an Agent Card
• Text and structured data parts, SSE streaming and durable replay
• Read-only doctor-install command that checks the plugin entry point and config
• hermes a2a setup, status and serve commands
• Registered as the a2a-bridge entry point in hermes_agent.plugins

When to use it

• Reading how an early A2A integration for Hermes was structured
• Understanding what the built-in Hermes A2A support replaced

Who it is for: Hermes Agent users curious about the origin of agent-to-agent support, who should use the built-in A2A for new setups.

How it fits with Hermes Agent

Built as a plugin for Hermes Agent, now superseded by A2A support that ships inside Hermes itself.

How to install Hermes A2A Bridge

These commands are copied from the project's README. Check the repository for the latest steps before you run them.

python -m pip install -e .
hermes-a2a-bridge doctor-install
hermes a2a setup
hermes a2a serve

Requirements: Python 3.11 or newer, and the a2a-bridge entry point listed under plugins.enabled in ~/.hermes/config.yaml.

Note: The repository is archived and read-only, superseded by the A2A support built into Hermes Agent.

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