Developer guide

GenAIScript welcomes contributions from the community. This document provides guidelines for setting up the development environment, building the project, and contributing to the codebase.

Setup

You can open this repo in GitHub CodeSpace/Docker to get the build environment needed.

• Go to https://github.com/microsoft/genaiscript
• Click on Code
• Select Create new Codespace
• Select the dev branch

Manual setup

• Install Node.JS LTS
• Run yarn

pnpm install --frozen-lockfile --prefer-offline

Build

You can do a full compile using esbuild.

pnpm build

or just the cli

pnpm build:cli

Pull Requests

You must create pull requests against the dev branch. The main branch is reserved for releases. The dev branch is the main development branch. It is where all new features and bug fixes are merged before being released to the public.

When creating a pull request, please ensure that your code adheres to the following guidelines:

• Follow the Microsoft Open Source Code of Conduct.
• Ensure that your code is well-documented and follows the project’s coding style.
• If possible, add tests for any new features or bug fixes.

Running local scripts

To run a script using the locally built cli,

pnpm genai <scriptid> ...

To run a sample script under the samples/sample folder:

pnpm run:script <scriptid> ...

In this case, it will use the samples/sample/.env file for the environment variables and workspace will be rooted at samples/sample.

Debugging local scripts

Open a JavaScript Debug Terminal and launch the script using

pnpm genai:debug <scriptid> ...

or for samples

pnpm run:script:debug <scriptid> ...

Logging

GenAIScript uses the debug library for logging. You can enable logging by setting the DEBUG environment variable to genai:*.

DEBUG=genaiscript:* pnpm genai <scriptid> ...

Web viewer

The web application (React 19) is meant to run both as a Visual Studio Code panel and a standalone viewer (playground). For testing purposes, standalone is the easiest.

• React 19, currently very little dependencies
• react-markdown + a few plugins to run the markdown
• vscode-elements is the design system we use as it mimics the vscode look and feel.

Use the following command to start the local web server:

pnpm serve

It will start a local server and rebuild the react client on file changes. It will not rebuild/restart the server on changes. There is no hot reload, you need to refresh the browser. If some state should be serialized, we should start adding it to the hash.

Visual Studio Code Extension development

Working on the VSCode involves launching the main project debugger, which opens a second VSCode instance with the GenAIScript extension.

You can set debug breakpoint anywhere in the GenAIScript typescript files and they will resolve.

• uninstall the official GenAIScript extension or it will clash with the locally built one
• open the Debug view in Vs Code
• select the Samples debugger configuration and click Run

Remember that the debugger is only attached to the extension; not the GenAIScript server.

Caveats

Launching the debugger sometimes fails but still unknown reasons. To work around this, open a terminal and run pnpm build once. Then launch the debugger again.

Docs

Run docs to launch the documentation site.

pnpm docs

Run this command to catch broken links

pnpm build:docs

Slides

All files slides/*slides.md will be compiled and deployed on build.

• run slides to launch the slide show (add the file name or it will default to slides.md)

pnpm slides [slides file name]

Learn more about Slidev on documentations. For diagrams, leverage mermaid or use draw.io, tldraw.

GenAIScripts

• Commit with auto-generated message

pnpm gcm

• Add doc to new or updated apis

pnpm genai:docs

• Generate images for blog posts

pnpm genai:blog-images

Packaging

To compile and package the Visual Studio Code extension, run the package script.

pnpm package

You will find the built package files, genaiscript.vsix, in the packages/vscode folder.

Release

Run the release script.

pnpm release

GitHub Pages are automatically updated on new release; or through manual trigger at https://github.com/microsoft/genaiscript/actions/workflows/docs.yml .

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.

When you submit a pull request, a CLA bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., status check, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

MCP Server Testing

Testing HTTP Transport Locally

To test the HTTP transport locally, follow these steps:

1. Start the HTTP MCP server in one terminal:

# Build the CLI first (if working from source)
pnpm build:cli

# Start HTTP server on default port 8003
node packages/cli/dist/src/index.js mcp --http --groups mcp

# Or use the global genaiscript if installed
genaiscript mcp --http --groups mcp

The server will display status information:

GenAIScript MCP server v2.3.9
│ Transport: HTTP (proxy-aware)
│ Endpoint: http://127.0.0.1:8003/mcp
│ Health: http://127.0.0.1:8003/health
│ Access: Local (127.0.0.1)
│ Proxy: Trusted (X-Forwarded-* headers supported)

2. Test the health endpoint to verify the server is running:

curl http://127.0.0.1:8003/health

You should see a response like:

{
  "status": "ok",
  "service": "genaiscript-mcp-server",
  "version": "2.3.9",
  "transport": "http"
}

3. Use the MCP Inspector to test the server functionality:

# Install and run the MCP inspector
npx @modelcontextprotocol/inspector http://127.0.0.1:8003/mcp

4. Configure a dual-transport setup for comprehensive testing by updating your .vscode/mcp.json:

.vscode/mcp.json

{
  "servers": {
    "genaiscript": {
      "type": "stdio",
      "command": "node",
      "args": [
        "${workspaceFolder}/packages/cli/dist/src/index.js",
        "mcp",
        "--cwd",
        "${workspaceFolder}",
        "--groups",
        "mcp"
      ],
      "envFile": "${workspaceFolder}/.env"
    },
    "genaiscript-http": {
      "type": "http",
      "url": "http://127.0.0.1:8003/mcp",
      "description": "GenAIScript MCP server via HTTP transport for testing HTTP connectivity"
    }
  }
}

This configuration allows you to test both stdio and HTTP transports side by side in MCP clients that support multiple servers.

5. Test with different ports and network configurations:

# Custom port
genaiscript mcp --http --port 3000

# Network accessible (use with caution)
genaiscript mcp --http --network --port 8080

# With startup script
genaiscript mcp --http --startup load-resources

HTTP Transport Features

The HTTP implementation includes:

• CORS support for web-based MCP clients
• Proxy awareness with X-Forwarded-* header support
• Session management for multiple concurrent connections
• Health check endpoint at /health for monitoring
• Error handling with graceful fallbacks
• Debug logging (enable with DEBUG=genaiscript:mcp:server)

You can use this script to load resources or do any other setup you need.