Here are two scenarios for using the FusionAuth API MCP Server, which is an MCP server that connects over STDIO and can be used to configure a FusionAuth instance.
- Local development — letting an agent configure FusionAuth and recording the steps for later automation
- Production read-only — using an agent to safely query a production instance
Preview Warning: The FusionAuth MCP server is a preview release and may break, change, or be discontinued. It is intended for development and test instances. Never give an MCP client unrestricted access to a production instance.
Prerequisites
- A running FusionAuth instance (local or remote)
- Node.js installed
- An MCP-compatible client (e.g., Claude Desktop)
Scenario 1: Local Development
This lets you configure FusionAuth and record steps to apply to other instances.
- Create a read-write API key. In your local FusionAuth instance, create an API key with the permissions you need. For full configuration work, you may want broad permissions, but always follow the principle of least privilege — for example, if you're only working with applications and themes, grant only those permissions.
- Configure your MCP client. For Claude Desktop on macOS, edit ~/Library/Application Support/Claude/claude_desktop_config.json to add the FusionAuth MCP server. Since you want full configuration access, omit the USE_TOOLS restriction (note: you'll need a model that can handle ~200k tokens):
{
"mcpServers": {
"fusionauth-mcp-api": {
"command": "npx",
"args": [
"@fusionauth/mcp-api"
],
"env": {
"API_KEY_APIKEYAUTH": "<your-read-write-api-key>",
"API_BASE_URL": "http://localhost:9011"
}
}
}
}
Restart Claude Desktop after saving.
- Verify the connection. Open Claude Desktop and ask:
"Which tools do you have access to?"
You should see a list of all FusionAuth API tools (300+).
- Configure FusionAuth using natural language. Now you can describe what you want in plain English. For example:
"Set up a custom registration form for the Pied Piper application. Require email address and password, but allow first name and favorite color to be optional. Put them all on one page."
Or:
"Add a user with an email address of test@example.com and a password of password."
The agent will make the appropriate API calls on your behalf.
- Export your configuration for automation. Once you've configured things the way you want, ask the agent to export the configuration so you can turn it into repeatable scripts:
"Please export the configuration for the Pied Piper application to a kickstart file."
"Export the current tenant configuration as a Terraform file."
This gives you a reproducible artifact you can commit to source control or use in CI/CD pipelines.
You can reduce tool scope. If you only need to work with specific operations (e.g., no deletes), you can reduce the tool list to improve performance and limit risk:
"env": {
"API_KEY_APIKEYAUTH": "<your-api-key>",
"API_BASE_URL": "http://localhost:9011",
"USE_TOOLS": "create,update,retrieve,search,other"
}
This omits the delete APIs and reduces the tool list by ~20%.
Scenario 2: Production Read-Only Queries with an Agent
The security model of this approach consists of three layers: the instance you connect to, the tool categories you expose, and the permissions on the API key itself. Combining a read-only API key with USE_TOOLS="retrieve,search" gives you defense in depth for production queries.
- Create a read-only API key. In your production FusionAuth instance, create an API key scoped to read-only operations only. This is the most important security step — the API key defines the ceiling of what the agent can do.
- Configure your MCP client with read-only tools. Edit your MCP client config to point at your production instance and restrict tools to retrieve and search only:
{
"mcpServers": {
"fusionauth-mcp-api-prod": {
"command": "npx",
"args": [
"@fusionauth/mcp-api"
],
"env": {
"API_KEY_APIKEYAUTH": "<your-read-only-api-key>",
"API_BASE_URL": "https://your-production-fusionauth-instance.com",
"USE_TOOLS": "retrieve,search"
}
}
}
}
Setting USE_TOOLS="retrieve,search" reduces the tool list by 66% and ensures the agent cannot create, update, patch, or delete anything. This is a second layer of defense.
- Verify read-only access. Ask the agent:
"Which tools do you have access to?"
Confirm that only retrieve and search tools are listed — no create, update, delete, or patch tools should appear.
The agent will use the read-only API tools to answer your questions without modifying anything.
