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

The annotations already convey readOnlyHint=true and destructiveHint=false, so the description does not need to restate safety. It adds the behavioral nuance of 'Poll' and 'latest SMS', but does not disclose details such as whether repeated polling is expected, what happens when no SMS exists, or timeout behavior. With annotations covering safety, a mid score is appropriate.

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 a single, front-loaded sentence that conveys the key action, target resource, and identifier type with no filler. Every word contributes to understanding the tool's purpose.

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 one-parameter read-only tool with an output schema present, the description is largely complete. It tells the agent what to do and what parameter to provide. Minor gaps such as explicit preconditions or whether polling should be repeated are not critical given the tool's simplicity and the annotations already supplied.

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 only defines rentalId as a string with no description, and schema description coverage is 0%. The description compensates by specifying that the rental id is a 'provider rental id string', which adds meaning beyond the raw schema type and disambiguates which identifier to pass.

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 uses a specific verb and resource — 'Poll latest SMS for a rental id' — and clarifies the identifier as 'provider rental id string'. Combined with the title 'Get SMS / OTP', an agent can clearly distinguish this tool from the many SMS sibling tools such as ucode_sms_rent_with_credits or ucode_sms_cancel_rental.

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 when to use the tool — after obtaining a rental id — but it does not explicitly state conditions, exclusions, or alternatives among the sibling tools. An agent must infer that this is the tool for retrieving the latest SMS/OTP for a rental, which is adequate but not directly guided.

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