Hamster

Hamster

Install Hamster. One plugin. Talk through hosted MCP or the CLI. Keep the plan on disk, then ship from it.

This is the Hamster product: Agent Plugins skills on every supported client, hosted MCP on every client that supports MCP and installs from GitHub or a marketplace, plus generated native execution workers on Claude Code, GitHub Copilot CLI, and Grok Build. The CLI is how the plan stays in this repo. It is not a second install.

Install

Installation differs by client. If you use more than one, install Hamster separately for each one.

Cursor

1. Customize → Add Marketplace → Import from GitHub.
2. Paste https://github.com/gethamster/plugin at User scope and select Import.
3. Open the Personal tab and select Add next to Hamster.

On Enterprise, an admin must allow marketplace imports. Once Hamster is on the Cursor marketplace, /add-plugin hamster works too:

/add-plugin hamster

Grok Bot is not a separate Hamster package. It uses the same Cursor account and plugin library, so the Cursor install above is the Grok Bot install. Do not run /add-plugin in the Grok Bot chat. If Grok Bot shows "Complete GitHub auth to sync installed plugins", complete GitHub auth when Grok Bot asks.

Claude Code

/plugin marketplace add gethamster/plugin

/plugin install hamster@hamster-plugins

Codex CLI

codex plugin marketplace add gethamster/plugin

codex plugin add hamster@hamster-plugins

You can also launch codex, run /plugins, and install hamster@hamster-plugins.

Codex Plugins Directory

The Hamster listing in OpenAI's Plugins Directory, used by Codex and ChatGPT, is a zip of this same plugin produced by node scripts/build-codex-bundle.mjs: the Codex manifest, the hosted MCP connector in .mcp.json, the skills, and the listing images. CI builds it on every push and uploads it as a workflow artifact, and the artifact download is the zip to upload to the directory.

One section differs. The zip replaces the "Install the CLI" section of skills/setup/SKILL.md with codex-directory/install-cli.md: when the CLI is missing, setup asks you to install it yourself from CLI binary instead of running the installer, then signs you in and syncs as usual.

Hamster connects to your workspace through the hosted MCP server. Coding skills require access to your repository and a shell.

Antigravity

From a clone of this repository:

agy plugin install ./plugins/hamster

Or from GitHub:

agy plugin install https://github.com/gethamster/plugin/plugins/hamster

Both install plugins/hamster, the folder every other client installs. The bare repository URL also works, but agy then imports the root as a Gemini CLI extension and drops the agents' model settings; running the command above replaces that install in place.

If Hamster 3.2 is already installed, uninstall it before you install 3.4. An in-place Antigravity install retains the four skill directories renamed in 3.4.

agy plugin uninstall hamster

agy plugin install https://github.com/gethamster/plugin/plugins/hamster

In the Antigravity app (2.15 or newer), authenticate hamster_hamster under Settings → Customizations → Installed MCP Servers. The plugin registers that server itself, so a manual hamster entry in mcp_config.json would add a second copy of every tool.

Using GitHub Copilot CLI, Gemini CLI, Grok Build, OpenCode, or Pi? See More install options.

More install options

GitHub Copilot CLI

copilot plugin marketplace add gethamster/plugin

copilot plugin install hamster@hamster-plugins

To sign in to the hosted MCP server, run /mcp auth hamster.

Gemini CLI

gemini extensions install https://github.com/gethamster/plugin

To sign in to the hosted MCP server, run /mcp auth hamster.

Grok Build

grok plugin install gethamster/plugin --trust

To sign in to the hosted MCP server, open /mcps, select hamster, and press i.

OpenCode

OpenCode takes the skills and the hosted MCP server in two steps. Run these in your project folder:

npx skills add gethamster/plugin --agent opencode

opencode mcp add hamster --url https://tryhamster.com/mcp

Add --global to npx skills add to install into ~/.agents/skills/ instead of the current project (opencode mcp add --url needs OpenCode 1.17.0 or later).

To sign in to the hosted MCP server, run opencode mcp auth hamster.

Pi

pi install npm:@tryhamster/pi

To track the repository instead of npm releases, run pi install git:github.com/gethamster/plugin.

The Pi package installs the skills only. To connect the hosted MCP server, add it and sign in:

pi mcp add hamster --url https://tryhamster.com/mcp

pi mcp login hamster

After install

1. Talk — hosted MCP at https://tryhamster.com/mcp, or hamster chat when MCP tools are unavailable and the CLI is signed in. Your client owns the Hamster sign-in.
2. Plan on disk — say Install Hamster, or run ship. The setup skill installs the CLI if needed, runs hamster auth login, and syncs the plan.
3. Ship — execute the brief already on disk. Nothing runs automatically on session start.

Skills

Claude Code and Copilot CLI list these as /hamster: . Cursor and Grok Build list them as / , and Pi as /skill: . In OpenCode, ask for one by name, or in OpenCode 2 mention it as @setup. The table uses the Claude form.

Four skills carry a -hamster suffix because Cursor invokes plugin skills as a bare /skill-name, and ask, plan, and resume are Cursor's own concepts — cursor-agent --mode takes plan and ask, --resume selects a session — so short names compete with them there. review is renamed with that family so Cursor's command list stays one convention. Claude Code namespaces plugin skills as / : and they cannot conflict, so on Claude the suffix is redundant and you type /hamster:ask-hamster. One skills tree serves every client, so that is the cost of being unambiguous on Cursor. ship, qa, retro, and setup shadow nothing and stay short.

/hamster:setup

The readiness path. Noninteractive check first (ensure-ready). If the CLI is installed and you are signed in, it runs hamster sync to refresh the plan. Otherwise it installs the CLI, opens login, and inits/syncs — only when you asked.

/hamster:ask-hamster

The gateway for open-ended questions that need Hamster's judgment across the workspace, such as how the code you're changing relates to priorities, blueprints, or decisions. Asks through the ask_hamster MCP tool when the client has it; otherwise hamster chat is the same ask path over the CLI. Direct reads and writes go to the named Hamster MCP tools instead. For example:

/hamster:ask-hamster I'm modifying auth middleware in apps/web/app/api/. What does our blueprint say about third-party integrations?

/hamster:ask-hamster I prototyped rate limiting in apps/api/middleware/rate-limit.ts. Which brief or initiative should this work belong to?

Follow-up questions continue the same Hamster conversation when they depend on the previous response.

/hamster:ship

The main orchestrator. Ship, plan-hamster, and resume-hamster share brief selection: a slug, UUID, or Hamster Studio URL takes precedence, followed by an exact title or short title (the part before a subtitle separator). Names ignore case, a leading “the”, a trailing “brief”, and trailing punctuation. A unique match proceeds without a selection question; ambiguous or partial-only names require clarification.

/hamster:ship user-authentication

/hamster:ship the Checkout reliability brief. /hamster:ship https://tryhamster.com/home/hamster/briefs/2de8d546-50ab-4dbd-a678-579ec8119f60

If no argument is given, presents an interactive picker of actionable briefs.

Flow: Readiness (setup/ensure-ready) → Setup (prereqs + live sync) → Brief selection → Inline wave scheduling (one confirmation) → Branch + merge base → Parallel wave execution (implement → validate + test → wave review → bisectable commits) → Final validation → Ask about PR creation

No plan generation or task elaboration occurs at any step — scheduling only organizes the pre-generated tasks into parallel waves.

/hamster:plan-hamster

Read-only analysis with optional deep review. Produces the execution plan without making changes.

/hamster:plan-hamster api-rate-limiting

After analysis, choose a review mode:

• CEO Review (Founder Mode) — 10-section deep dive from first principles
• Eng Review (Architecture Mode) — 4-section technical review with ASCII diagrams and test plan
• Quick Analysis — Just the plan

/hamster:resume-hamster

Resumes an interrupted execution. Auto-detects the brief from the git branch name (feature/{key}-{id}-{slug}), in-progress tasks, or a provided argument.

/hamster:resume-hamster

/hamster:resume-hamster user-authentication

/hamster:review-hamster

Paranoid two-pass code review for the current feature branch:

• Pass 1 (CRITICAL): SQL safety, race conditions, auth boundaries, enum completeness, secrets
• Pass 2 (INFORMATIONAL): Side effects, magic numbers, dead code, test gaps, type coercion, time safety
• Interactive resolution for critical findings with fix/acknowledge/false-positive options

/hamster:review-hamster

/hamster:qa

Systematic testing with 4 modes:

/hamster:qa diff        # Test only what changed (default on feature branches)

/hamster:qa full # Full test suite with coverage /hamster:qa quick # 30-second lint + typecheck + smoke tests /hamster:qa regression # Changed files + dependents, flag new failures

Includes issue taxonomy (functional/type-safety/integration/performance/coverage-gap) and optional fix loop.

/hamster:retro

Engineering retrospective from git history:

/hamster:retro          # Last 7 days (default)

/hamster:retro 14 # Last 14 days /hamster:retro 30 # Last 30 days /hamster:retro 24h # Last 24 hours

Produces: metrics table, hourly distribution, session analysis, hotspots, PR sizes, per-contributor deep dive with praise and growth suggestions, trends vs last retro, and a narrative summary.

Execution workers

Canonical worker protocols live in plugins/hamster/skills/ship/references/agents/. plugins/hamster/agents/task-executor.md and plugins/hamster/agents/wave-reviewer.md are generated native adapters (registratio