agent-to-agent

name	agent-to-agent
description	Agent-to-agent (a2a) delegation invokes another coding-agent harness as a subagent and continues the same delegated conversation across turns. Use when an agent needs to summon Codex, Claude Code, OpenCode, or Hermes Agent through a shell or terminal tool, retain the child session, send follow-up instructions, or coordinate ongoing agent-to-agent work.
version	1.1.0
argument-hint	<codex|claude-code|opencode|hermes> [task to delegate]

Agent to Agent

Delegate a bounded task from one agent harness to another while retaining the child harness's session identifier for follow-up turns.

Run children asynchronously

Start potentially long-running children with the orchestrator's native background facility so a foreground shell timeout cannot terminate them. Keep the returned task or terminal identifier and poll it until completion.

Treat backgrounding as process-lifetime management, not proof of progress. Follow the target harness reference for its progress and terminal-state signals.

Codex

When Codex is the orchestrator, launch the external harness in a tool-managed background terminal. It continues after the initiating tool call returns and can be inspected later.

Claude Code

When Claude Code is the orchestrator, pass run_in_background: true on the Bash tool call; never nohup. The run is exempt from the foreground timeout, persists across turns, and re-invokes the agent when the process exits. Incremental output can be read on demand mid-run (TaskOutput), or a Monitor can watch the log for a condition.

OpenCode

When OpenCode is the orchestrator, the Bash tool blocks until the child exits or the timeout fires (default 120 s). There is no native background facility. If the child may exceed the timeout, launch it in a new tmux window in the orchestrator's main session and poll its output file for progress; see the target's reference for its event format and progress signals.

Hermes Agent

When Hermes is the orchestrator, call its terminal tool with background=true and notify_on_complete=true. Retain the returned process session ID and use the process tool's poll, log, wait, and kill actions for lifecycle control. Do not use shell-level nohup or &; native background execution keeps the process observable and preserves completion notification.

This workflow runs a resumable external child-harness session. Hermes's native delegate_task is useful for ordinary delegation, but is not a substitute when the parent must retain and explicitly resume an external child conversation.

Select the target

• For Codex, read references/codex.md and follow it.
• For Claude Code, read references/claude-code.md and follow it.
• For OpenCode, read references/opencode.md and follow it.
• For Hermes Agent, read references/hermes.md and follow it.

Keep one child session per delegated task. Give the child the goal, working directory, relevant context, constraints, and expected result. Review its output before relying on it or applying consequential actions.