@civic/playwright-tokensaver-proxy

A single stdio MCP server that proxies to Playwright MCP and adds a token-saving run_code_cheap tool.

What it does

• Runs as one stdio MCP server (easy to drop into MCP client config)
• Launches upstream Playwright MCP via stdio:
  • default command: npx -y @playwright/mcp@latest
• Clones browser_run_code into run_code_cheap
• Keeps all Playwright tools exposed
• Adds guidance to browser_* tools to prefer run_code_cheap when full output is not needed
• Rewrites run_code_cheap calls through a harness and returns compact results:
  • success
  • failure

Behavioral contract for run_code_cheap

Your provided code should return:

{ "success": true }

Anything else is treated as failure:

• throw
• { "success": false }
• invalid return shape

Usage

Claude Code

claude mcp add playwrightsave -- npx -y @civic/playwright-tokensaver-proxy

MCP client config (JSON)

{
  "mcpServers": {
    "playwrightsave": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@civic/playwright-tokensaver-proxy"],
      "env": {}
    }
  }
}

Environment variables

• PLAYWRIGHT_COMMAND: default npx
• PLAYWRIGHT_ARGS: comma-separated args, e.g. -y,@playwright/mcp@latest,--headless,--isolated
• PLAYWRIGHT_ARGS_JSON: JSON array alternative to PLAYWRIGHT_ARGS (takes precedence)
• PLAYWRIGHT_HEADLESS: set to true/1/yes to append --headless when using default args
• PLAYWRIGHT_ISOLATED: set to true/1/yes to append --isolated when using default args
• PLAYWRIGHT_CWD: optional working directory for the upstream Playwright MCP process