Spawner

io.github.Flosk6Published by GitHub account Flosk6v2.2.1Updated Oct 24, 2026

Preview environments on your self-hosted Spawner server: a copy of your app for each git branch

VerifiedSTDIODesktop onlyCloud & InfrastructureDeveloper Tools

Overview

AI-generated overview

MCP server for a self-hosted Spawner instance, letting an assistant create, inspect, run commands in and tear down per-branch preview environments.

What you can do
  • Create and update the preview environment for the current branch from a worktree, uncommitted changes included
  • Check environment status, list environments, read resource stats and get environment URLs
  • Read environment logs, optionally filtered to error lines
  • Run commands inside an environment's services
  • Create share links for people without an account, and delete environments
When to use it
Useful when a team runs its own Spawner server and wants a coding agent to spin up, debug and clean up preview environments for branches without leaving the editor or chat.
Requirements
Node.js 20 or later with the spawner-cli package installed globally, plus a reachable self-hosted Spawner server. Log in interactively with spawner login, or set SPAWNER_URL and SPAWNER_TOKEN for CI or containers. An admin must add the project in the dashboard before the first environment is created.
Before you install
The server acts with the CLI's login and rights. spawner_exec runs arbitrary commands in environment services and spawner_down deletes environments; both are marked destructive, and whether the client asks first depends on its permission settings. SPAWNER_TOKEN is a personal API token granting that account's access. Share links expose an environment to people without an account.

Installation

In SourceWeft

  1. Open Spawner in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

spawner-cli

The command line and MCP server of Spawner. Spawner is an open source, self-hosted preview environment manager: a copy of your app for each git branch, on your own server, with its own URLs, database and logs, for teams and their coding agents.

With spawner, developers and coding agents create, update and delete environments from a worktree, uncommitted changes included, run commands in them and read their logs.

Install

bash
npm install -g spawner-cli

It needs Node.js 20 or later, and a Spawner server: install one with a single command. Every server also serves the CLI of its own version at /api/v1/cli/spawner.

Log in

bash
spawner login https://spawner.preview.example.com

Type the code it shows in the dashboard and approve the login: the CLI stores a personal token. In CI or a container, SPAWNER_URL and SPAWNER_TOKEN replace the login.

Commands

bash
# write .spawner/, and offer to add the instructions for coding agentsspawner init
# the environment of the current branch, from this worktreespawner up --wait
# run a command in a servicespawner exec feat-login db -- psql -U app -c "select * from users"
# only the error lines, stack traces kept wholespawner logs feat-login api --errors
# a link for someone without an accountspawner share feat-login
spawner down feat-login

Before the first spawner up of a project, an admin adds the project in the dashboard (Projects, New project). The other commands: status, ls, stats, capacity, url, shell, stop, start, sleep, wake, extend, token, whoami and logout.

Commands print JSON with --json and exit with stable codes: 4 when the environment failed, 6 when the quota or the server's capacity is reached, 7 when .spawner/ was refused.

MCP server

spawner mcp is an MCP server on stdio, with the login and the rights of the CLI. In Claude Code:

bash
claude mcp add spawner -- spawner mcp

In a project's .mcp.json, or Cursor's .cursor/mcp.json:

json
{  "mcpServers": {    "spawner": { "command": "spawner", "args": ["mcp"] }  }}

It has nine tools: spawner_up, spawner_status, spawner_list, spawner_logs, spawner_exec, spawner_stats, spawner_url, spawner_share and spawner_down. spawner_exec and spawner_down are marked destructive: whether a client asks before running them depends on the client and its permission settings.

Documentation

Source: github.com/Flosk6/Spawner. License: Apache-2.0.

Source: apps/cli/README.md at commit b9c01c6

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

2
  1. v2.2.1LatestOct 11, 2026
  2. v2.2.0Oct 10, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts