Subtext MCP Server

Subtext CLI — drive the Subtext MCP server from your terminal

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What is the Subtext MCP server?

Subtext CLI — drive the Subtext MCP server from your terminal. Exposed over MCP by the subtext mcp server, that capability becomes something an assistant can invoke while it works, not something you go and do afterwards.

What it actually does

A command-line interface for the Subtext MCP server. Open a browser, inspect the page, click things, take screenshots — from a shell or CI script.

The Subtext CLI opens a hosted browser session and lets you drive it: navigate, inspect the DOM, click, type, take screenshots, and close — all from a shell. Built for AI agents and CI pipelines, but works just as well for manual spot-checks.

Its toolset

Everything the assistant can do here goes through one of these:

  • Namespace — Type
  • live — passthrough
  • comment — passthrough
  • doc — passthrough
  • artifact — passthrough
  • privacy — passthrough
  • review — passthrough
  • tunnel — native
  • sightmap — native
  • auth — native
  • version — native
  • Verify — The Verify tool exposed by this server

Configuration

You will need 6 environment variables: SUBTEXT_API_KEY, SUBTEXT_REGION, RELAY_URL, SIGHTMAP_URL, TRACE_URL, TUNNEL_ID. The server will not start without them, which is usually why the tools fail to appear on a first run. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

Adding it to your client

Being a remote server, there is no local install. You register the endpoint with your client, authorise it once, and the tools appear.

When to reach for it

This sits in the browser automation group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Subtext's toolset — Namespace, live, comment and 10 more — is a fair guide to whether it matches your workflow. It is maintained by GitHub Actions; worth a glance at recent repository activity before you build anything load-bearing on it.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.

Caveats

  • Your data travels to the provider's service, so the usual questions apply about what you send and what they retain.
  • With 13 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch Subtext.
  • Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the subtext mcp server does with a few real requests.

Available tools

ToolWhat it does
NamespaceType
livepassthrough
commentpassthrough
docpassthrough
artifactpassthrough
privacypassthrough
reviewpassthrough
tunnelnative
sightmapnative
authnative
versionnative
VerifyThe Verify tool exposed by this server.
Sightmaps.sightmap/ YAML files in your project root map CSS selectors and routes to semantic component names. After uploading, the hosted browser resolves those names in snapshots, screenshots, and interaction targets. Upload the

How to install the Subtext MCP server

{
  "mcpServers": {
    "subtext": {
      "command": "npx",
      "args": ["-y", "@subtextdev/subtext-cli"],
      "env": {
        "SUBTEXT_API_KEY": "your-value",
        "SUBTEXT_REGION": "your-value",
        "RELAY_URL": "your-value",
        "SIGHTMAP_URL": "your-value",
        "TRACE_URL": "your-value",
        "TUNNEL_ID": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
SUBTEXT_API_KEYCredential the server authenticates with.Yes
SUBTEXT_REGIONConfiguration value read at startup.Optional
RELAY_URLEndpoint or connection string the server talks to.Yes
SIGHTMAP_URLEndpoint or connection string the server talks to.Yes
TRACE_URLEndpoint or connection string the server talks to.Yes
TUNNEL_IDConfiguration value read at startup.Optional

Example prompts to try

  • Use Subtext to Namespace.
  • Use Subtext to live.
  • Use Subtext to comment.

Frequently asked questions

It connects Subtext to MCP-compatible AI assistants such as Claude and Cursor, exposing 13 tools (Namespace, live, comment, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Subtext directly.