han

Han is a suite of AI skills and agents for solo (or small-team) product engineers. It combines evidence-based planning, test-driven implementation, full documentation maintenance, deep code review, and architectural analysis into a team of specialists you can dispatch from Claude Code.

What this plugin does

Han turns planning, implementation, review, and documentation work that would normally take a team into a set of deterministic skills you run from Claude Code.

Each skill dispatches specialist agents, such as project managers, adversarial reviewers, investigators, architectural analysts, and testing and security specialists, to do the judgment-heavy work. It then folds their findings into an artifact you can trust.

The skills are designed to compose. You can plan a feature, then plan its implementation, then iterate on the plan, then build it test-first, then review the resulting code, then write the PR description. All through named skills that hand off to each other cleanly.

Read Concepts for the skill-and-agent model that runs through the whole plugin.

For Solo Product Engineers and Small Teams

Han is purpose-built for solo product engineers and small teams, instead of large teams or enterprise. This does not mean it can't work in larger teams, though. Read about why Han's focus is solo product engineers and small teams to understand Han's positioning and what it does not bring to the table.

Installation

Claude Code

Add the Test Double skills marketplace to Claude Code, then install the plugin:

/plugin marketplace add testdouble/han
/plugin install han@han

Han ships as multiple plugins:

Plugin	Type	What it brings
han	parent	the parent plugin that brings in han-core, han-planning, han-coding, han-github, and han-reporting
han-core	bundled	research, analysis, and documentation skills plus every agent
han-planning	bundled	planning skills you reach for before implementation
han-coding	bundled	coding skills you reach for while working in code
han-github	bundled	GitHub-facing skills like posting a code review on a PR
han-reporting	bundled	reporting skills like the stakeholder summary
han-feedback	opt-in	skill for capturing post-session feedback on Han skill runs
han-atlassian	opt-in	skills for publishing docs and work items to Atlassian products
han-linear	opt-in	skill for publishing work items to Linear (requires a Linear MCP server)
han-plugin-builder	opt-in	carries the guidance and skills for building your own skills, agents, and plugins

Installing han@han pulls in the bundled suite (the meta-plugin plus han-core, han-planning, han-coding, han-github, and han-reporting), and is the right choice for most people. If you do not want the planning, coding, GitHub, or reporting skills, install han-core@han instead, and add other specific plugins as desired.

For the full picture and a quick "which one do you need?" guide, see Choosing a Han plugin.

Codex

Add this repo as a Codex marketplace:

codex plugin marketplace add testdouble/han

Codex does not yet support meta-plugins like han@han (see openai/codex#23531,) so install the Han packages directly:

codex plugin add han-core@han
codex plugin add han-planning@han
codex plugin add han-coding@han
codex plugin add han-github@han
codex plugin add han-reporting@han

Install han-feedback, han-atlassian, han-linear, or han-plugin-builder separately when you want those opt-in packages.

Documentation

• Concepts. Skill vs. agent, and how they compose. Read once before using the plugin.
• Choosing a Han plugin. The full suite vs. core only, the han-planning, han-coding, han-github, and han-reporting dependencies on han-core, and a quick guide to which one to install.
• Quickstart. Five paths for five common situations. Each path is a short sequence of skills.
• Skills Index. All skills, grouped by purpose.
• Agents Index. All agents, grouped by role.
• Sizing. The small / medium / large model that decides how many agents the swarming skills dispatch.
• YAGNI. The evidence-based "You Aren't Gonna Need It" rule every planning, review, and architecture skill applies.
• Evidence. What counts as evidence in Han, how to characterize how strong it is, and what to do when no evidence exists at all.
• Readability. The shared output standard every reader-facing skill applies as it writes, so its human-facing deliverable leads with the main point and reads consistently across skills.
• Changelog. What's new in each version of the plugin.

How-To Guides

• How-to guides. End-to-end recipes for planning a feature, revising a plan after the build starts, accelerating your understanding of unfamiliar code, triaging and investigating a bug, running an effective code review, and researching a decision. Pick one when you want the full walkthrough, not only the path.
• How to provide feedback on Han. Send the maintainers structured feedback on a skill or agent run.
• Extend Han via dependencies. Add your own custom skills on top of Han.
• Build a plugin that depends on Han. Ship a plugin that builds on Han's skills and agents.

Contributing to Han

• Contributing. Adding or editing skills, agents, and documentation.
• Create a new skill. Build a new slash command from scratch with /skill-builder.
• Create a new agent. Build a new subagent from scratch with /agent-builder.

Maintenance and Support

• Maintenance horizon: Indefinitely maintained, best-effort. No SLA.
• Project type: Personal project, with some Test Double support
• How to report issues: GitHub Issues, with expected best effort for response within 2 weeks.

Han is an open source product of Test Double, and maintained by the following people:

• River Lynn Bailey: Creator, and primary maintainer

LEGAL NOTICES

Copyright 2026 Test Double, Inc. Distributed under the MIT license.