delete_rule

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

With no annotations provided, the description fully carries the burden of behavioral disclosure. It explicitly states the tool is destructive, requires user confirmation via MCP elicitation, and cannot be undone because Mail.app does not version rule history. These are critical operational traits that an agent must know before calling, and they are clearly articulated.

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 two sentences, with the purpose statement first and the safety/irreversibility warning second. Every word is necessary; there is no fluff or repetition. The front-loading of the action makes it immediately scannable.

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?

Given the tool's simplicity (one parameter) and the presence of an output schema, the description covers all essential aspects: the action, the index requirement, the destructive nature, and irreversibility. An agent can correctly call this tool with the information provided, including knowing to obtain the index from list_rules (implied by the schema description). Nothing critical is missing.

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?

The input schema already describes the single parameter as '1-based positional index from list_rules' with 100% coverage. The tool description merely repeats the same information ('by 1-based positional index') without adding new semantics. Baseline of 3 is appropriate since the schema does the heavy lifting.

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 the action: 'Delete a Mail.app rule' with a specific method ('by 1-based positional index'). The verb and resource are unambiguous and distinguish it from sibling tools like delete_mailbox or delete_template. The mention of 'Mail.app' and 'rule' makes the target explicit.

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 implies usage conditions: it requires a 1-based index (which must come from list_rules) and mandates user confirmation before running. It does not explicitly name alternatives or when-not conditions, but the unique scope (Mail.app rule) and the destructive nature give sufficient context for an agent to decide when to invoke it. It could benefit from an explicit 'use after list_rules' note, but the schema parameter description already covers that.

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