AGS Extend SDK MCP Server

A Model Context Protocol (MCP) server that gives AI assistants (VS Code Copilot, Cursor, Claude, Gemini, Antigravity) the AccelByte Extend SDK as additional context — so they can answer questions about the SDK and generate correct Extend SDK code.

What It Does

• Search Extend SDK symbols (functions and models) by name, tags, or description (fuzzy matching)
• Describe specific symbols — parameters, fields, imports, examples, return types, required permissions
• Scaffold a new Extend app from a template repository via the create-extend-app prompt

It serves SDK reference for four languages — C#, Go, Java, and Python. You pick the language per connection through the URL path (see Choose your language).

AccelByte hosts the Extend SDK MCP Server for you — you don't need to install or run anything locally. Just point your AI assistant at the hosted MCP URL for your language. There's no sign-in: the server only exposes read-only SDK reference data. Prefer to run it yourself? See Running Locally & Self-Hosting.

Using the Tools

Once connected, your assistant has access to these tools. In your assistant's chat, try the example prompts below — give permission to run the tools when requested.

search-symbols

Search Extend SDK symbols by name, tags, or description, with fuzzy matching. Returns a paginated list of summaries.

"Search for symbols related to user" · "Find symbols for inventory"

describe-symbols

Get full details for specific symbols by ID — fields, parameters, imports, example usage, return type, and required permissions.

"Describe the AdminCreateUser@iam and User@iam symbols"

create-extend-app

A prompt template that clones an Extend app template repository and opens it (in a Dev Container when available) so you can start from a working sample.

Invoke the create-extend-app prompt and follow the scenario / template / language completions.

[!TIP] When coding with this MCP server, start from an Extend SDK getting-started sample or an Extend app template instead of a blank project, and add relevant source files as context for better results.

Documentation

• Installation Guide — followed by the Quick Install prompt; readable on its own
• Running Locally & Self-Hosting — Docker, environment variables, HTTP endpoints, development, and releasing the image

Contributions

This repository is published as-is. For bug reports and questions, please open an issue.

Quick Install

Paste this into your AI coding assistant — it will fetch the install guide, ask you a couple of questions, and configure everything for you:

Install the AGS Extend SDK MCP server for me. Fetch and follow the instructions at
https://raw.githubusercontent.com/AccelByte/ags-extend-sdk-mcp-server/refs/heads/master/INSTALL.md

Works in VS Code Copilot, Cursor, Claude Code, Antigravity, and Gemini CLI.

Claude Desktop users: The simplest path is Settings → Connectors → Add custom connector (Name: extend-sdk, URL: your MCP URL) — no AI installer needed. See Claude Desktop below.

If you want to use the Quick Install prompt above, switch to the Code tab first (Chat and Cowork can't edit your config file).

Prefer to do it yourself? See Manual Install below.

Manual Install

Step 1: Choose your language and get your URL

The MCP URL is the hosted server's base URL followed by /extend-mcp/{language}:

https://<mcp-server-host>/extend-mcp/{language}

• <mcp-server-host> is the host of your organization's deployment — ask your AccelByte administrator if you're not sure.
• One hosted instance serves every language. To switch language later, just change the trailing path segment (e.g. /extend-mcp/python → /extend-mcp/go). Requesting an unknown language returns HTTP 400.
• The base path (/extend-mcp) with no language serves the server's configured default language.

No hosted instance? You can run the server yourself with Docker — see Running Locally & Self-Hosting.

Step 2: Configure your client

The server uses Streamable HTTP transport. Clients that support HTTP transport connect to the URL directly. Clients that only support stdio transport use mcp-remote as a bridge.

Need mcp-remote? It runs via npx, so you need Node.js 18+ with npx available — verify with npx --version. No global install required.

Substitute your URL from Step 1 wherever you see <URL> below.

Visual Studio Code (Copilot)

.vscode/mcp.json in your workspace (or user settings.json):

{
  "servers": {
    "extend-sdk": {
      "type": "http",
      "url": "<URL>"
    }
  }
}

If your client can't reach an HTTP server, swap to: { "command": "npx", "args": ["-y", "mcp-remote", "<URL>"] }.

See the VS Code MCP documentation.

Cursor

.cursor/mcp.json in your workspace (or user settings):

{
  "mcpServers": {
    "extend-sdk": {
      "type": "http",
      "url": "<URL>"
    }
  }
}

If your client can't reach an HTTP server, swap to: { "command": "npx", "args": ["-y", "mcp-remote", "<URL>"] }.

See the Cursor MCP documentation.

Claude Code

claude mcp add --transport http extend-sdk <URL>

Fallback (stdio-only environments): claude mcp add extend-sdk -- npx -y mcp-remote <URL>.

See the Claude Code MCP documentation.

Antigravity

mcp_config.json in your project root:

{
  "mcpServers": {
    "extend-sdk": {
      "type": "http",
      "url": "<URL>"
    }
  }
}

If your client can't reach an HTTP server, swap to: { "command": "npx", "args": ["-y", "mcp-remote", "<URL>"] }.

See the Antigravity MCP documentation.

Gemini CLI

gemini mcp add --transport http extend-sdk <URL>

Fallback (stdio-only environments): gemini mcp add extend-sdk -- npx -y mcp-remote <URL>.

See the Gemini CLI MCP documentation.

Claude Desktop

Option A — Custom Connector (recommended)

1. Open Settings → Connectors → Add custom connector (under the "Customize" area).
2. Fill in Name: extend-sdk and Remote MCP server URL: your <URL> from Step 1.
3. Save.

Don't see "Add custom connector"? Some Team and Enterprise plans disable custom connectors via workspace policy. If the option is missing or greyed out, use Option B.

Option B — mcp-remote config file (fallback)

Edit claude_desktop_config.json:

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

{
  "mcpServers": {
    "extend-sdk": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "<URL>"]
    }
  }
}

Restart Claude Desktop after saving.

Running it yourself

Prefer to run the server locally (stdio) or host the HTTP server yourself? See Running Locally & Self-Hosting for Docker usage, environment variables, HTTP endpoints, developing from source, and releasing the image.

Troubleshooting

Tool calls fail / the server returns 400

Check the language in your URL path. It must be one of csharp, go, java, or python (e.g. /extend-mcp/go). An unknown language returns HTTP 400.

Client can't connect to the HTTP URL

Some clients only support stdio transport. Switch that client to the mcp-remote bridge config shown in Step 2. It needs Node.js 18+ with npx available (npx --version).

"Connection refused" or the host is unreachable

Confirm the <mcp-server-host> and full URL are correct (ask your AccelByte administrator), and that your network can reach it.