List GPUs

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

Annotations already declare readOnly/idempotent/non-destructive/open-world, so the description correctly focuses on what annotations can't convey: an auth-dependent response shape (prices without a key, availability plus max GPUs per pod with one). That is genuinely useful behavioral disclosure; rate limits or caching behavior are not mentioned.

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: what it returns first, then the auth-dependent behavior, then the two parameter hints. Every sentence carries information and nothing is repeated from the schema or annotations.

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?

An output schema exists, so return-value detail is correctly omitted, and the auth-tier and filtering behavior are covered. The remaining hole is the undefined `rental_type` vocabulary, which an agent would need in order to actually pass a non-default value.

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 0%, so the description must carry parameter meaning and it largely does — "spot" for the preemptible tier and `min_vram_gb` as a VRAM filter. The gap is that the schema defines `rental_type` as a free-form string with no enum, and the description never states the full set of valid values or the "demand" default.

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 states a specific verb and resource: show GPU types available for rent now, with per-GPU hourly USD prices. It is clearly distinguishable from mutation-oriented siblings like create_pod or estimate_pod. It does not explicitly contrast itself with the near-twin `cpus` sibling, so it stops short of the top score.

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?

It gives concrete usage context: it works anonymously for prices but needs a key for live availability, and it tells the agent to use `rental_type` "spot" for the cheaper preemptible tier. What's missing is any statement about when to prefer this over `estimate_pod` (cost estimation) or `machines` before creating a pod.

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