Configure Policies

Define fine-grained access control rules for your MCP server using JSON-based policies and CLI tools.

Policy Management CLI

Use the eunomia-mcp CLI in your terminal to manage your MCP authorization policies.

Creating Your First Policy

# Create a default policy configuration file
eunomia-mcp init

# Create policy configuration file with custom name
eunomia-mcp init --policy-file my_policies.json

# Generate both policy configuration file and a sample MCP server
eunomia-mcp init --sample

You can edit the created mcp_policies.json policy configuration file to your liking. Refer to the templates for example policies and rules.

Validating Policies

# Validate your policy file
eunomia-mcp validate mcp_policies.json

Deploying Policies

# Push your policy to Eunomia server
eunomia-mcp push mcp_policies.json

# Push your policy and overwrite existing ones
eunomia-mcp push mcp_policies.json --overwrite

Info

You need the Eunomia server running for the push operation.

Workflow:

1. Initialize: eunomia-mcp init
2. Customize: Edit generated policy file
3. Validate: eunomia-mcp validate mcp_policies.json
4. Start Server: eunomia server
5. Deploy: eunomia-mcp push mcp_policies.json
6. Run: Run your MCP server with middleware

MCP Context Extraction

Methods Mapping

The middleware automatically maps MCP methods to authorization checks:

MCP Method	Resource URI	Action	Middleware behavior
tools/list	mcp:tools:{name}	list	Filters the server's response
resources/list	mcp:resources:{name}	list	Filters the server's response
prompts/list	mcp:prompts:{name}	list	Filters the server's response
tools/call	mcp:tools:{name}	call	Blocks/forwards the request to the server
resources/read	mcp:resources:{name}	read	Blocks/forwards the request to the server
prompts/get	mcp:prompts:{name}	get	Blocks/forwards the request to the server

Contextual Attributes

The middleware extracts contextual attributes from the MCP request and passes them to the decision engine; these attributes can therefore be referenced inside policies to define dynamic rules.

Attribute	Type	Description	Sample value
method	str	The MCP method	tools/list
component_type	str	The type of component: tools, resources or prompts	tools
name	str	The name of the component	file_read
uri	str	The MCP URI of the component	mcp:tools:file_read
arguments	dict (Optional)	The arguments of the execution operation	{"path": "file.txt"}

You now have an MCP server with authorization that enforces customized policies. Explore agent authentication to further secure your server.