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

Annotations already cover read-only/idempotent/non-destructive/open-world, so the bar is lower, yet the description adds real operational context: results are cached ten minutes, sorted tightest-first, and limited to GPUs with at least two signals. It does not discuss rate limits or freshness beyond the cache window, but the added behavioral detail is substantial.

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 the cost and scope front-loaded, then scoring semantics, then the pointer to paid alternatives. The telegraphic phrasing ('score only', 'tightest first') is efficient rather than padded, though it reads slightly clipped.

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 structure needn't be explained, and the description still supplies everything an agent needs to interpret the result: the 0–100 scale endpoints, sort order, minimum-signal inclusion rule, cache staleness, and where richer detail lives. Nothing material 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 tool takes zero parameters, which is the baseline-4 case; there is nothing for the description to disambiguate. The description correctly spends no space on parameter syntax.

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?

Names a specific resource (capacity stress score per GPU model) with an explicit scope (latest day, score only) and distinguishes itself from the sibling capacity_stress and capacity_board tools by stating that components and inputs live in those paid endpoints. An agent can tell this apart from its siblings without opening a 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 leading 'Free.' plus 'score only' and the pointer to the paid /capacity/stress and /capacity/board clearly signals when this tool is the right choice (headline number only, no component detail). It stops short of an explicit 'use this instead of X when' formulation, but the routing condition is readily inferable.

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