han

Han: For the Solo Product Engineer

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-communication, han-core, han-documentation, han-research, han-planning, han-coding, han-github, and han-reporting
han-communication	bundled	the foundational plugin beneath every other: the shared readability standard and writing-voice profile, plus the skills and agent that apply them
han-core	bundled	the shared specialist agent roster, the project-discovery skill, the /pairing collaborative working mode, and the canonical rule files
han-documentation	bundled	documentation skills: project docs, architectural decision records, and runbooks
han-research	bundled	pre-planning knowledge-work skills: research, gap analysis, and issue triage, plus the research-analyst 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-ddd	opt-in	strategic Domain-Driven Design analysis: bounded context discovery and an evidence-backed domain and context map
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-communication, han-core, han-documentation, han-research, han-planning, han-coding, han-github, and han-reporting), and is the right choice for most people. If you want only one slice of Han, install a single layer such as han-documentation@han or han-coding@han instead (each brings the shared han-core agents along), 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,) and it resolves no dependencies, so install the Han packages directly — starting with the foundational han-communication, which the prose-producing packages depend on:

codex plugin add han-communication@han
codex plugin add han-core@han
codex plugin add han-documentation@han
codex plugin add han-research@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, han-ddd, or han-plugin-builder separately when you want those opt-in packages. Because Codex resolves no dependencies, install han-communication alongside han-atlassian (its wrapped prose-producing skills source the shared readability standard from it).

Documentation

• Concepts. Skill vs. agent, and how they compose. Read once before using the plugin.
• Plugin index. Every plugin with a one-line scent and a link to its README, the full suite vs. a single layer, the layer 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. Every skill, alphabetized, with a scent line and a link to its long-form doc.
• Agents index. Every agent, alphabetized, with a scent line and a link to its long-form doc.
• Workflows. The map of which skills chain together, with flow diagrams for the branching chains.
• Configuration. The optional .han/config.md files, one personal and one per project, that set an output base directory, a default swarm size, a writing-voice profile, and extra agents for Han skills.
• 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
• Tamika Nomara: Core contributor
• Aaron Frerichs: Core contributor
• All contributors: Misc and greatly appreciated!

LEGAL NOTICES

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