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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds useful context about the maximum number of properties and the metrics compared, but it does not disclose return format, error behavior, or what happens if an ID is invalid. This is acceptable given the annotations.

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, front-loaded with the core action and scope. It lists the key metrics efficiently and ends with the necessary input instruction. Every sentence earns its place with no redundancy.

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?

For a simple read-only comparison tool with one parameter and no output schema, the description covers the purpose, input, and metrics. It is concise and self-sufficient. It could mention behavior for invalid or non-existent property IDs, but that is a minor gap given the tool's simplicity.

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 schema provides full coverage for the only parameter property_ids with 'Array of property IDs to compare (max 5)', so the description adds no significant semantic detail beyond restating the parameter. Baseline 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 tool's function: 'Compare up to 5 vacation rental properties side-by-side on key metrics...' This is a specific verb+resource action, and it distinguishes itself from sibling tools like get_vacation_rental_details or search_vacation_rentals by focusing on side-by-side comparison.

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 the usage scenario (comparing multiple properties) and specifies the input format ('Pass an array of property_ids') and limit ('up to 5'). However, it does not explicitly contrast with alternatives such as individual detail or search tools, so the when-to-use guidance is implied rather than explicit.

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