Keryx Framework
Keryx: The Fullstack TypeScript Framework for MCP and APIs
What is Keryx Framework?
Keryx Framework is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to keryx: the fullstack typescript framework for mcp and apis
Keryx: The Fullstack TypeScript Framework for MCP and APIs
This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- Keryx: The Fullstack TypeScript Framework for MCP and APIs
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx keryxConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Keryx Framework
Keryx is a fullstack TypeScript framework built on Bun that lets you write a single Action class and have it automatically work as an HTTP endpoint, WebSocket handler, CLI command, background task, and MCP tool — all with the same Zod-validated inputs, middleware chain, and response shape. Every action is automatically registered as an MCP tool when the MCP server is enabled, so AI agents connecting via Claude Desktop or VS Code can discover and call your application's business logic through the standard Model Context Protocol with OAuth 2.1 authentication. It is a ground-up rewrite of ActionHero with first-class MCP support, Drizzle ORM, and Bun as the runtime.
Prerequisites
- Bun runtime installed (https://bun.sh — run: curl -fsSL https://bun.sh/install | bash)
- PostgreSQL database server running and accessible
- Redis server running (for background tasks via node-resque)
- An MCP-compatible client such as Claude Desktop or VS Code with Copilot to connect to your Keryx app's MCP endpoint
Create a new Keryx project
Use bunx to scaffold a new Keryx application.
bunx keryx new my-app
cd my-appConfigure environment variables
Copy the example env file and set your PostgreSQL and Redis connection details.
cp .env.example .env
# Edit .env and set:
# DATABASE_URL=postgresql://user:pass@localhost:5432/myapp
# REDIS_URL=redis://localhost:6379
# MCP_SERVER_ENABLED=trueInstall dependencies and start the development server
Install all workspace dependencies and start Keryx in development mode.
bun install
bun devWrite an Action (available as HTTP, CLI, and MCP tool automatically)
Define an Action class with a name, description, Zod inputs, and a run method. It is automatically available at PUT /api/user via HTTP and as the user-create MCP tool.
// src/actions/userCreate.ts
export class UserCreate implements Action {
name = "user:create";
description = "Create a new user";
inputs = z.object({
name: z.string().min(3),
email: z.string().email(),
});
web = { route: "/user", method: HTTP_METHOD.PUT };
async run(params: ActionParams<UserCreate>) {
const user = await createUser(params);
return { user };
}
}Connect an MCP client to your Keryx app
Point your MCP client at the /mcp endpoint of your running Keryx server. All your actions are automatically discoverable as MCP tools.
Keryx Framework Examples
Client configuration
Claude Desktop configuration connecting to a local Keryx app's MCP endpoint. All actions registered in the Keryx app become available as MCP tools automatically.
{
"mcpServers": {
"my-keryx-app": {
"url": "http://localhost:8080/mcp"
}
}
}Prompts to try
Example prompts for interacting with a Keryx application through Claude. Replace action and parameter names with those defined in your specific Keryx app.
- "List all available tools in my Keryx app"
- "Create a new user with name 'Evan' and email '[email protected]'"
- "Run the user:list action and show me all users"
- "Call the product:search action with query 'headphones' and limit 10"
- "Enqueue a background task for report:generate with date range last_month"Troubleshooting Keryx Framework
bun dev fails with database connection errors
Ensure PostgreSQL is running and the DATABASE_URL in .env is correct (format: postgresql://user:password@host:5432/dbname). Run the database migrations after the first start: cd example/backend && bun run migrations.
MCP tools are not visible in the connected client
Set MCP_SERVER_ENABLED=true in your .env file and restart the Keryx server. Actions are only registered as MCP tools when this flag is enabled. Verify the server is reachable at http://localhost:8080/mcp from the client.
Action not appearing as an MCP tool despite being registered
Check that the action class does not have an mcp property set to exclude it from MCP exposure. Action names with colons (e.g., user:create) are converted to dashes for MCP tool names (user-create). Confirm the tool name in your MCP client matches this convention.
Frequently Asked Questions about Keryx Framework
What is Keryx Framework?
Keryx Framework is a Model Context Protocol (MCP) server that keryx: the fullstack typescript framework for mcp and apis It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Keryx Framework?
Follow the installation instructions on the Keryx Framework GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with Keryx Framework?
Keryx Framework works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Keryx Framework free to use?
Yes, Keryx Framework is open source and available under the MIT license. You can use it freely in both personal and commercial projects.
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