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Rules files - Agent Toolkit for AWS

Rules files

Most AI coding agents support project-level configuration files — often called rules files — that provide persistent instructions the agent follows in every session. For example, you might have a rules file that tells your agent to always write TypeScript in strict mode, or to use a specific testing framework.

The Agent Toolkit for AWS includes a recommended rules file that tells your agent how to work with AWS — for example, to use the AWS MCP Server for API calls, to search for available skills before starting a task, and to prefer infrastructure-as-code over direct CLI commands.

The Agent Toolkit for AWS includes a recommended rules file that covers using the AWS MCP Server, discovering skills, verifying against documentation, and following infrastructure-as-code best practices. You can find the latest version of this file in the Agent Toolkit for AWS repository on GitHub. Copy the content into the appropriate file for your agent.

Where to put the rules file

The file name and location depend on your agent:

Rules file locations by agent
Agent Project rules Location
Claude Code CLAUDE.md Project root
Codex AGENTS.md Project root
Cursor .cursor/rules/*.mdc .cursor/rules/ directory
Kiro .kiro/steering/*.md .kiro/steering/ directory

For Claude Code and Codex, add the content above to your existing CLAUDE.md or AGENTS.md file, or create a new one in your project root. For Cursor, create a new .mdc file in the .cursor/rules/ directory (for example, .cursor/rules/aws.mdc). The legacy .cursorrules file is still supported but deprecated.

Customization

The recommended rules file is a starting point. Customize it for your project — for example, specifying which AWS Region to use, which VPC to deploy into, or which naming conventions to follow for resources.