List Platform-Tier Rental Services

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 safety profile is covered. The description adds a useful domain constraint beyond annotations — that platform-tier rentals are locked to ONE chosen service per number — which is material behavioral context. Consistent with calibration for annotation-covered read tools, a 3 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?

Three tight sentences with zero filler. The primary purpose and returned data are front-loaded in the first sentence, the critical lock constraint follows, and the usage directive closes it. Every sentence 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?

Despite having no output schema, the description compensates by naming the returned data (physical stock counts and retail price) and explaining the platform-tier lock constraint. Combined with 100% schema coverage and rich annotations, an agent has what it needs to call this correctly. Only a more explicit return-format note would push it higher.

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 both parameters (country_code as ISO-2, duration_hours defaulting to 24) are already documented. The description only echoes the country scope ('in a given country') and adds nothing about format, syntax, or valid values beyond what the schema provides. Baseline 3 is correct when the schema carries the parameter documentation load.

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?

States a specific verb ('List'), a precise resource ('services available for platform-tier rental'), and a scope ('in a given country'). It distinguishes itself from the sibling virtualsms_list_services by qualifying the platform-tier rental subtype and adds concrete detail about what is returned (physical stock counts and retail price). An agent can tell it apart from related rental tools without opening any schema.

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 phrasing 'Use this to pick a valid service code before creating one' gives implicit workflow guidance that this precedes rental creation. However, it does not explicitly name alternative siblings (e.g., virtualsms_list_services for non-platform rentals, or virtualsms_rentals_available for available numbers) or state when NOT to use it, so the differentiation is inferred rather than explicit.

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