GPU market summary

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description adds value by specifying the behavioral scope: it is a one-call overview and includes index health and feed freshness, which are useful beyond the structured annotations. It does not contradict 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, no filler. The first sentence front-loads the purpose and enumerates the return contents compactly; the second gives a concrete usage trigger. Every clause adds information.

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 parameters, no output schema, and a rich annotation set, the description carries the burden of explaining what the agent will receive. It does so thoroughly, covering price data, trend data, source counts, freshness, index health, and the biggest mover. Nothing essential is missing for calling this 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?

The tool has zero parameters, and the schema coverage is effectively complete because there is nothing to document. The description still clarifies that the tool returns a market-wide summary rather than a specific GPU price, which is the closest thing to parameter context needed here.

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 ('One-call overview of the GPU rental market') and enumerates exactly what is included: per-model prices, 7-day changes, weekly ranges, source counts, feed freshness, index health, and biggest mover. This clearly distinguishes it from sibling tools that focus on a single price, comparison, or history.

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 gives an explicit trigger: 'Use this first when asked "what do GPUs cost right now"'. This provides clear context for when to choose this tool, though it does not explicitly name sibling alternatives or state when not to use it.

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