agent trio

A minimal, all natural language bootstrap for brand new or existing repos of any kind that want to follow principled agentic coding. Zero code.

Once upon a time, humans hand-wired computers to program them. Thankfully, someone invented silicon chips coding agents.

agent trio is not a swarm framework. It does not optimize for agent count or lines of code output. It is for introducing just the right amount of friction. You should spend tokens to maximize judgement and quality, not output or wasteful rework. agent trio helps you do that. See the intro blog post for more.

How is this different from /review? /review is a one-shot critique of git state; agent-trio holds out .trio/criteria.md before building, so the review phase checks the implementation against criteria set before it existed.

How is this different from openai/codex-plugin-cc? That plugin ships cross-provider adversarial review as a skill; agent-trio is the plan → build → review → learn loop around it, and the reviewer can invoke /codex:adversarial-review as one of its inputs.

Recommendations. I recommend you select a more efficient (but not deliberately cheap) builder model, and a similar-or-stronger reviewer model. Keep your expensive tokens for reasoning and judgement. You could for example use Codex + GPT-5.4 (xhigh) as the planner and reviewer, and GPT-5.4 (med) for the builder. Claude Code can spawn Opus reviewer and Sonnet builder subagents. Or go rainbow providers — you just need to configure your agents accordingly.

Installation

Agent-trio installs as a plugin that injects the workflow contract and agents into your coding agent session.

Claude Code:

Register the plugin marketplace, then install:

/plugin marketplace add haplesshero13/agent-trio
/plugin install agent-trio@trio-marketplace

Or add to your project's .claude/settings.json:

{
  "plugins": ["agent-trio@git+https://github.com/haplesshero13/agent-trio.git"]
}

Codex:

codex plugin marketplace add haplesshero13/agent-trio

Then open Codex, run /plugins, select Agent Trio, and install it. For local development from this checkout, run codex plugin marketplace add ..

The skill operates in consult, plan, or execute mode depending on what you ask — it will not create planning files for read-only questions or simple guidance. Builder and reviewer agents are available when Codex runs inside a checkout; without them, the head instance acts locally and still honors the full artifact contract.

See .codex/INSTALL.md for full details and examples.

OpenCode:

If agent-trio is available from npm:

Add agent-trio to the plugin array in your opencode.json:

{
  "plugin": ["agent-trio"]
}

For local development or git-checkout installation, clone the repo and add a global shim under ~/.config/opencode/plugins/; see .opencode/INSTALL.md.

Restart OpenCode. The plugin registers the repo-root skills/ directory and the .opencode/agents/ wrappers, so using-agent-trio, @builder, and @reviewer become available.

See .opencode/INSTALL.md for details.

Interactive setup

Once agent-trio is installed, run the setup flow to pick builder/reviewer models and peer-review preferences without hand-editing config:

• Claude Code: /agent-trio:setup
• OpenCode / Codex / any other platform: ask the head agent to "run agent-trio setup" — it will read setup/agent-trio-setup.md and walk you through the same choices.

The setup flow only writes to files it tells you about first; see setup/agent-trio-setup.md for the full list of files it may create or modify per platform.

Quick file guide

• AGENTS.md: developer guide — repo structure, how to make changes, validation checklist
• skills/using-agent-trio/SKILL.md: the workflow contract (imperative, with first-session bootstrap and delegation)
• agents/builder.md, agents/reviewer.md: the builder/reviewer agent definitions
• .trio/learnings.md: the checked-in lessons that still change how the next loop runs
• .trio/plan.md, .trio/handoff.md, .trio/review.md: the gitignored agent coordination files
• .claude/agents/, .codex/agents/: provider wrappers around the roles
• plugins/agent-trio/.codex-plugin/, .agents/plugins/: Codex plugin manifest and marketplace metadata
• .opencode/: OpenCode plugin — plugins/agent-trio.js, package.json, INSTALL.md
• .claude-plugin/: plugin manifest for marketplace distribution
• commands/setup.md: /agent-trio:setup slash command for Claude Code
• setup/agent-trio-setup.md: platform-neutral interactive setup instructions