Create Rules Engine rules with the MCP server

You can create a Rules Engine rule by describing it to a coding agent connected to the build server of the Azion MCP servers. The build server writes to your account, so the agent first calls the tool with dry_run, which returns the API request without sending it. You review that request, and then the agent sends it. For the same rule built by hand in Azion Console, follow Create an application rule.

Prerequisites

• A coding agent connected to the build server, https://build-mcp.azion.com/mcp. To connect one, refer to MCP server quickstart.
• A personal token with permission to change the application. The build server sends every request with this token.
• The ID of the application to add the rule to.

Create a rule with your agent

The build server creates a request rule with create_request_rule and a response rule with create_response_rule. Both take the application_id, a name, the criteria, and the behaviors of the rule. To create a rule that redirects an old path:

The new rule appears in the Rules Engine tab of the application, in the list of its phase. To change the order in which rules run, ask the agent to call reorder_request_rules or reorder_response_rules.

Read the fields of a rule

The inputs of create_request_rule follow the rule shape of the Azion API v4:

• criteria: an array of one to five groups, each with one to ten criteria. A criterion carries a conditional (if, and, or or), a variable such as ${uri}, an operator such as starts_with or matches, and an argument. For every operator, refer to Operators. For how criteria combine, refer to Conditionals.
• behaviors: an array of one to ten behaviors. A behavior type is lowercase, such as redirect_to_301 or set_cache_policy, and a behavior that takes an argument carries it in attributes.value.
• active: whether the rule runs, true by default.
• description: optional text of up to 1,000 characters.

${request_uri} requires Application Accelerator on the application. Without it, match ${uri} instead, as Variables explains.

Create a cache setting and the rule that applies it

A set_cache_policy behavior applies a cache setting, which holds the TTL, and its attributes.value is the ID of that cache setting. Create the cache setting first. For example, to cache images for a day:

Create the rule as a request rule. Set Cache Policy runs only in the Request Phase, as Set Cache Policy states. When one goal needs two cache settings, such as one TTL for static assets and one for /api/, create one rule per criterion, each with its own cache setting. A single rule with both criteria joined by or applies both behaviors to both kinds of request.

Create a firewall rule

A rule for Rules Engine for Firewall belongs to the secure server, https://secure-mcp.azion.com/mcp, not to the build server. Connect it, then ask the agent for the rule. The agent calls create_firewall_rule, which also takes dry_run. To change the order of firewall rules, the agent calls reorder_firewall_rules.

Every rule the agent creates is also reachable without it: through Azion Console, as Create an application rule describes; through the API, as the API section of Rules Engine for Applications describes; or from a JSON file, with Azion CLI rules-engine. When the agent lists no create_request_rule tool, the build server is not connected; Troubleshoot the MCP server covers the fix.

Next steps