CEL attributes for IAM Access policies

This document describes the Common Expression Language (CEL) attributes and functions that you can use when writing conditional expressions in IAM Unified Access Policies (Access policies) for Agent Gateway.

To learn more about Access policy concepts, see IAM Access policies overview. To learn how to configure Access policies, see Create IAM Access policies.

Available CEL attributes

In your Access policies, you can define conditions with conditional expressions. The expressions can contain multiple sub-expressions. The destination resource type that you use in each relational sub-condition determines which attributes you can use.

For example, in the following condition, in the sub-expression destination.agent_registry.mcp_server.tool.name.startsWith('getStatements'), the resource type is MCP server, the attribute is destination.agent_registry.mcp_server.tool.name, and startsWith() is the CEL function.

destination.agent_registry.mcp_server.name == '/projects/my-project/locations/us-central1/mcpServers/finance-data-service' &&
destination.agent_registry.mcp_server.tool.name.startsWith('getStatements')

The attributes described in the following table are available for each resource type:

Destination resource type	Attribute	Details
Agent Registry	destination.is_registered	Value type Boolean Supported values true, false Supported operations ==, !=
	destination.agent_registry.resource_type	Value type String Supported values 'AGENT', 'ENDPOINT', 'MCP_SERVER', 'SKILL' Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
	destination.agent_registry.location	Value type String Supported values Google Cloud location ID (for example, 'global', 'us-central1') Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
	destination.agent_registry.project_id	Value type String Supported values Google Cloud project ID Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
Agent	destination.agent_registry.agent.name	Value type String Supported values Agent resource name (projects/PROJECT_ID/locations/LOCATION/agents/AGENT_NAME) Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
MCP Server	destination.agent_registry.mcp_server.name	Value type String Supported values MCP server resource name (projects/PROJECT_ID/locations/LOCATION/mcpServers/MCP_SERVER_NAME) Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
	destination.agent_registry.mcp_server.method	Value type String Supported values MCP method name (for example, 'tools', 'prompts', 'resources') Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
	destination.agent_registry.mcp_server.tool.name	Value type String Supported values Tool name (for example, 'search_code', 'execute') Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
	destination.agent_registry.mcp_server.tool.annotations.read_only_hint	Value type Boolean Supported values true, false Supported operations ==, !=
	destination.agent_registry.mcp_server.tool.annotations.destructive_hint	Value type Boolean Supported values true, false Supported operations ==, !=
	destination.agent_registry.mcp_server.tool.annotations.idempotent_hint	Value type Boolean Supported values true, false Supported operations ==, !=
	destination.agent_registry.mcp_server.tool.annotations.open_world_hint	Value type Boolean Supported values true, false Supported operations ==, !=
	destination.agent_registry.mcp_server.prompt.name	Value type String Supported values Prompt name Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
	destination.agent_registry.mcp_server.resource.name	Value type String Supported values Resource name Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
Endpoint	destination.agent_registry.endpoint.name	Value type String Supported values Endpoint resource name (projects/PROJECT_ID/locations/LOCATION/endpoints/ENDPOINT_NAME) Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
Unregistered Destination	destination.unregistered.host	Value type String Supported values Hostname (for example, 'google.com', 'example.com') Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
	destination.unregistered.path	Value type String Supported values Request path (for example, '/admin', '/api/v1') Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()
	destination.unregistered.method	Value type String Supported values HTTP method (for example, 'get', 'post', 'put', 'delete') Supported operations ==, !=, in, .startsWith(), .endsWith(), .matches()

Note: Unregistered host and path attributes support the following CEL functions: STARTS_WITH, ENDS_WITH, and CONTAINS, or methods startsWith(), endsWith(), and contains().

What's next

• Create IAM Access policies
• Manage IAM Access policies
• Troubleshoot IAM Access policies

Overview

Agent Gateway overview

Get an overview of Agent Gateway.

Guide

Configure content and business policies

Learn how to configure content and business policies.

Guide

Test policies

Learn how to test policies.