create_rule

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds valuable behavioral info beyond annotations: mentions backup creation (safety) and potential need for restart. This supplements the annotations which only note non-readonly and non-destructive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is only two sentences, with no wasted words. The purpose is stated first, followed by essential behavioral notes. Front-loaded and compact.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has nested objects well-documented in schema, and the description adds backup and restart info. However, it lacks any mention of return values or error handling (e.g., what happens if creation fails), which would be helpful for a creation tool with no output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all parameters well. The tool description does not add any parameter-specific meaning beyond what is already there, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Create a new Mail.app rule', using a specific verb and resource. It distinguishes itself clearly from sibling tools like update_rule, delete_rule, and list_rules.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides context: a backup is made and restart may be needed. However, it does not explicitly state when to use this tool versus alternatives like update_rule, or when not to use it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.