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

Annotations already declare read-only, idempotent and non-destructive, so safety is covered. The description goes beyond them by defining each tier's meaning (guaranteed vs community vs spot), noting default volume (3 cheapest per tier, up to 50 for full), and stating prices are provider-published and dated with non-comparable normalizations.

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?

Front-loaded with what is returned before the tier and comparability caveats, and no sentence is pure filler. The telegraphic style is dense but compact enough for the amount of semantics it conveys.

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?

With no output schema, the description carries the return-shape burden and does so: one block per tier, each with its own cheapest offer and per-configuration breakdown. Combined with tier definitions and the price caveat, an agent has enough to call and interpret the tool correctly.

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 coverage is 100%, so the baseline is 3. The description adds real meaning beyond the schema by explaining tier semantics and the cheapest_by_gpu_count normalization rule (single-GPU vs multi-GPU node prices are not comparable), which affects how the agent should interpret results.

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 resource and scope: rental offers for one GPU type, broken out by tier, with the fields returned named (provider, price, GPU count, billing, region). It is clear what the tool returns, but it does not explicitly differentiate itself from the sibling 'cheapest', which sounds like it also surfaces low-price offers.

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 routes the agent to list_gpus for the required GPU id and warns that tiers and per-configuration prices are never comparable, which is useful usage context. However, it never says when to prefer this tool over 'cheapest', 'compare_providers' or 'estimate_cost', so alternative selection is left to inference.

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