About Terrarium
Terrarium is an HTML review tool for Claude Code, where an agent publishes artifacts for human feedback. Comments are anchored to specific text, and the agent can retrieve feedback, submit revisions, and repeat the review cycle.
Key features
- 01Publish HTML artifacts
- 02Browser review with anchored comments
- 03Retrieve structured feedback
- 04Push revised versions
- 05Reply to and resolve comments
Use cases
- 01Have reviewers inspect agent-generated HTML
- 02Collect requested changes on specific passages
- 03Iterate on a page from comments until approval
MCP support
It provides a remote MCP server over Streamable HTTP, with seven tools for managing artifacts, comments, and versions.
Configuration
Remote servers need no local install. Pick your client, then copy the config or install in one click.
https://www.tryterrarium.com/api/mcpclaude mcp add --transport http nelsonsantryhkd-terrarium https://www.tryterrarium.com/api/mcp{"mcpServers":{"nelsonsantryhkd-terrarium":{"type":"http","url":"https://www.tryterrarium.com/api/mcp"}}}Open in Cursor{"servers":{"nelsonsantryhkd-terrarium":{"type":"http","url":"https://www.tryterrarium.com/api/mcp"}}}Open in VS Code{"mcpServers":{"nelsonsantryhkd-terrarium":{"type":"http","url":"https://www.tryterrarium.com/api/mcp"}}}{"mcpServers":{"nelsonsantryhkd-terrarium":{"serverUrl":"https://www.tryterrarium.com/api/mcp"}}}Run commands in a terminal; paste JSON into the client’s MCP config and restart. Servers that need sign-in will prompt on first connect.
https://www.tryterrarium.com/api/mcpAuth requiredTools
Details
From the project READMETerrarium plugin for Claude Code
Give your agent a place to show its work to humans. Terrarium hosts the HTML your agent builds; humans review it in the browser with comments anchored to exact passages; the agent pulls that feedback over MCP, pushes fixes, and repeats until approved.
Install
/plugin marketplace add nelsonsantryhkd/terrarium-plugin
/plugin install terrarium@terrarium
Then mint a token at tryterrarium.com/connect
and make it available as TERRARIUM_PAT:
export TERRARIUM_PAT="samus_pat_…"
(Or just ask your agent to set Terrarium up — the bundled skill walks it through the whole flow, including sending you to /connect for the token.)
What it ships
- MCP server (
.mcp.json) — Terrarium's remote server over Streamable HTTP with 7 tools:list_artifacts,publish_artifact,get_artifact,pull_comments,push_version,reply_to_comment,resolve_comment. - Skill (
skills/terrarium/) — teaches the publish → review → fix loop, including theterrarium-feedback/1payload,expectedVersionfreshness, and comment-thread etiquette.
The protocol
pull_comments returns a versioned, structured payload
(terrarium-feedback/1) designed to be stable enough to build agents against:
review state, typed comment threads (change_request / question / bug),
text anchors with live resolution status, and reply chains. Evolution within
/1 is additive-only.
Comments
New to MCP?
From what the protocol is to installing your first server, these answers cover most first questions.
An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.