Capsule MCP — Install & Live Demo

Why use it

Key features

Secure WebAssembly sandbox for AI agents - run untrusted Python or JavaScript without trusting it.
Maintained by capsulerun (community)
Written in Rust
284+ GitHub stars at last check
Open source on GitHub

Live Demo

What it looks like in practice

capsule-runtime.replay ▶ ready

0/0

Install

Pick your client

~/Library/Application Support/Claude/claude_desktop_config.json · Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "capsule-runtime": {
      "command": "TODO",
      "args": [
        "See README: https://github.com/capsulerun/capsule"
      ]
    }
  }
}

Open Claude Desktop → Settings → Developer → Edit Config. Restart after saving.

~/.cursor/mcp.json · .cursor/mcp.json

{
  "mcpServers": {
    "capsule-runtime": {
      "command": "TODO",
      "args": [
        "See README: https://github.com/capsulerun/capsule"
      ]
    }
  }
}

Cursor uses the same mcpServers schema as Claude Desktop. Project config wins over global.

VS Code → Cline → MCP Servers → Edit

{
  "mcpServers": {
    "capsule-runtime": {
      "command": "TODO",
      "args": [
        "See README: https://github.com/capsulerun/capsule"
      ]
    }
  }
}

Click the MCP Servers icon in the Cline sidebar, then "Edit Configuration".

~/.codeium/windsurf/mcp_config.json

{
  "mcpServers": {
    "capsule-runtime": {
      "command": "TODO",
      "args": [
        "See README: https://github.com/capsulerun/capsule"
      ]
    }
  }
}

Same shape as Claude Desktop. Restart Windsurf to pick up changes.

~/.continue/config.json

{
  "mcpServers": [
    {
      "name": "capsule-runtime",
      "command": "TODO",
      "args": [
        "See README: https://github.com/capsulerun/capsule"
      ]
    }
  ]
}

Continue uses an array of server objects rather than a map.

~/.config/zed/settings.json

{
  "context_servers": {
    "capsule-runtime": {
      "command": {
        "path": "TODO",
        "args": [
          "See README: https://github.com/capsulerun/capsule"
        ]
      }
    }
  }
}

Add to context_servers. Zed hot-reloads on save.

claude mcp add capsule-runtime -- TODO 'See README: https://github.com/capsulerun/capsule'

One-liner. Verify with claude mcp list. Remove with claude mcp remove.

Use Cases

Real-world ways to use Capsule

Use Capsule for its primary workflow

👤 Developers using AI coding agents ⏱ ~10 min beginner

When to use: You need the capability: Secure WebAssembly sandbox for AI agents - run untrusted Python or JavaScript without trusting it.

Prerequisites

MCP server installed — See https://github.com/capsulerun/capsule for install instructions

Flow

Install

Install Capsule following the README at https://github.com/capsulerun/capsule✓ Copied

→ MCP server appears in your client's available tools/skills
Invoke

Use Capsule to complete the task described in its docs.✓ Copied

→ Agent calls the relevant tool/skill and returns a result

Outcome: Working integration with the capabilities advertised by the project.

Pitfalls

README is the source of truth; details here may lag upstream — Check https://github.com/capsulerun/capsule for the latest setup steps and tool list

More

Resources

📖 Read the official README on GitHub

🐙 Browse open issues

🔍 Browse all 400+ MCP servers and Skills