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.
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 (project managers, adversarial reviewers, investigators, architectural analysts, testing and security specialists) to do the judgment-heavy work, 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.
- New to han? → Start with Concepts, then the Quickstart.
- Looking for a specific skill? → Skills Index. 17 skills grouped by purpose.
- Looking for a specific agent? → Agents Index. 21 agents grouped by role.
- Wondering how the agent swarms scale? → Sizing. The small / medium / large dispatch model used by
/architectural-analysis,/code-review,/gap-analysis,/iterative-plan-review,/plan-a-feature, and/plan-implementation. - Wondering why a skill said "YAGNI"? → YAGNI. The evidence-based rule every planning, review, and architecture skill applies before committing items to an artifact.
- Writing or editing a skill or agent? → Contributing.
Seventeen skills, grouped by the moment you reach for them. Each category links to the full long-form docs through the Skills Index.
Spec what to build, plan how to build it, sequence it into phases, and stress-test the plan before you commit.
/plan-a-feature. Build a feature specification from scratch through an evidence-based interview./plan-implementation. Turn a feature specification into an implementation plan through a project-manager-led team conversation./plan-a-phased-build. Split a body of work into a numbered sequence of vertical-slice phases, each independently demoable./iterative-plan-review. Stress-test an existing plan through multiple codebase-grounded review passes.
Write the code, test-first, through a disciplined red-green-refactor loop.
/tdd. Drive a feature or behavior through a BDD-framed red-green-refactor loop with an enforced observed-failure gate, applying coding standards and ADRs in green and refactor.
Find out why something is broken, with evidence to back it.
/issue-triage. Classify a vague issue or bug report, identify missing information, assess severity and reproducibility, and recommend the right next skill./investigate. Evidence-based investigation of bugs, failures, and unexpected behavior, with adversarial validation of the proposed fix.
Get a second set of eyes on code that already exists.
/code-review. Comprehensive code review of the current branch or specified files./gh-pr-review. Run a code review against a GitHub PR and post the review as comments./architectural-analysis. Deep architectural analysis of a module: coupling, data flow, concurrency, risk, and SOLID alignment./gap-analysis. Compare two artifacts (spec vs. implementation, PRD vs. shipped feature) and produce a plain-language report indexed by stable gap IDs./test-planning. Produce a prioritized test plan for a branch or directory.
Produce reference material every other skill (and future-you) benefits from.
/project-discovery. Scan the repository for languages, frameworks, tooling, and structure./project-documentation. Create and maintain documentation for features, systems, and components.
Codify how the team works.
/coding-standard. Create and update coding standards from existing patterns or evidence-based research./architectural-decision-record. Create, extract, or convert architectural decision records.
Turn work into something shareable outside the repo.
/update-pr-description. Generate a PR description from the current branch's changes.
Not sure which category fits your situation? The Quickstart has path-by-path guidance for the most common ones.
Add the Test Double skills marketplace to Claude Code, then install the plugin:
/plugin marketplace add testdouble/han
/plugin install han@han
- Concepts. Skill vs. agent, and how they compose. Read once before using the plugin.
- Quickstart. Four paths for four common situations. Each path is a short sequence of skills.
- Skills Index. All 17 skills, grouped by purpose.
- Agents Index. All 21 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.
- Contributing. Adding or editing skills, agents, and documentation.
- Changelog. What's new in each version of the plugin.
- 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
Copyright 2026 Test Double, Inc. Distributed under the MIT license.