Get Rental Details

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description does not need to repeat that. It adds value by disclosing the exact response contents (including received SMS), which is helpful context not present in the schema or annotations. It does not contradict any 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?

Two sentences with zero waste. The first sentence front-loads the purpose and response details; the second gives actionable usage guidance. Every word earns its place.

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 single-parameter read-only tool, the description is complete: it lists the response fields, states the prerequisite for the ID, and the annotations cover safety semantics. Nothing an agent needs to call it correctly 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 schema already fully documents rental_id ('Rental ID to retrieve') with 100% coverage. The description adds no extra meaning beyond that, other than implying the ID comes from list_rentals. Baseline 3 is appropriate because the schema does the heavy lifting and the description offers no additional parameter-level detail.

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 (get) and the specific resource (a rental by ID), then enumerates the concrete fields returned (tier, phone number, country, service lock, status, expiry, and any received SMS). It also differentiates from list_rentals by noting the prerequisite, making the tool's role unambiguous.

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 explicitly tells the agent when to use this tool versus the alternative: 'Use list_rentals first if you do not have the rental_id.' This is a direct, actionable usage guideline that names the sibling and the condition that selects between them.

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