| name | hermes-a2a-setup |
| description | Install and configure hermes-a2a plugin for agent-to-agent communication. Based on Google's A2A protocol. When user says "a2a"、"agent对话"、"agent通信"、 "给agent发消息"、"跟别的agent说话"、"agent间通信"时加载。
|
| tags | ["a2a","agent-to-agent","plugin","hermes"] |
| version | 1 |
hermes-a2a Plugin Setup
Source repo: hermes-a2a (iamagenius00 on GitHub)
Hermes plugin for peer-to-peer agent communication via Google's A2A protocol.
Zero external dependencies, pure Python stdlib.
Prerequisites
- Hermes Agent v2026.4.23+ (plugin API with register_command)
- CLI mode only (gateway does NOT load plugins)
Install Steps
- Clone repo and run install.sh — copies 7 files to plugins directory
- CRITICAL: Run
hermes plugins enable a2a — plugins are opt-in
- Set A2A_ENABLED=true and A2A_PORT=8081 in environment
- Restart CLI session (plugin loads at session start)
Pitfall: Plugin Must Be Explicitly Enabled
The plugin system requires explicit enablement. After install, run:
hermes plugins enable a2a
Without this, the plugin is discovered but NOT loaded.
User plugins are opt-in — only bundled backends auto-load.
Pitfall: Gateway Does NOT Load Plugins
Only CLI mode supports A2A. Gateway (Telegram/Discord/Feishu) won't start the A2A server.
Plugin hooks only fire in CLI conversation loop.
Tools Exposed
| Tool | Description |
|---|
| a2a_discover | Check remote agent's Agent Card |
| a2a_call | Send message to remote agent |
| a2a_list | List configured remote agents |
Configuring Remote Agents
Add entries under a2a.agents in config yaml:
a2a:
agents:
- name: "friend"
url: "https://friend-a2a-endpoint.example.com"
description: "My friend's agent"
auth_token: "their-bearer-token"
Security
- Bearer token auth (localhost-only without token)
- 20 req/min rate limit per IP
- 9 prompt injection patterns filtered
- Outbound secrets redacted
- Audit log at a2a_audit.jsonl
Architecture
Remote Agent sends A2A JSON-RPC to localhost:8081
→ task_queue.enqueue()
→ webhook trigger fires agent turn
→ pre_llm_call hook injects message into current session
→ agent replies with full context
→ post_llm_call captures response
→ response returned synchronously (120s timeout)
→ exchange persisted to a2a_conversations/
Files
| File | Purpose |
|---|
| init.py | Entry point, registers hooks/tools/server |
| server.py | A2A HTTP server + webhook + task queue |
| tools.py | a2a_discover, a2a_call, a2a_list |
| security.py | Injection filtering, redaction, rate limit |
| persistence.py | Saves conversations to disk |
| schemas.py | Tool schemas |
| plugin.yaml | Plugin manifest |
Routing Keywords (in skill-router.md)
A2A agent 对话、agent 间通信、给别的 agent 发消息 → A2A 插件
