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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description still adds meaningful non-obvious context: the values are published statistics or single-site cases and must not be averaged across differing scopes, which directly affects how an agent may legitimately interpret results.

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?

Four labeled micro-sections (Purpose/Guidelines/Limits/Ex) make it scannable and front-loaded with the resource definition. Slightly formulaic labeling costs a little efficiency, but no sentence is wasted.

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 values need no explanation, and the description covers purpose, usage, and a key interpretation constraint. It is essentially complete for a read-only lookup tool, with only the absence of an explicit negative case keeping it from a 5.

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% with three documented parameters (keyword, language, response_format), so the schema already carries the semantics. The description adds only an example of a zero-argument call and no extra meaning about filtering, language selection, or output format, so the baseline 3 is appropriate.

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 Purpose line names a specific resource and scope: PUE benchmarks and green-rating figures for compute facilities. That is far more precise than the tool name alone, though the sibling differentiation is only implicit (the closest relative, calculate_compute_energy_cost, appears under Guidelines rather than being contrasted in the Purpose statement).

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 states when to use it ('efficiency questions'), names a companion tool to pair with and the condition for pairing ('when a load figure is available'), and adds a scope caveat ('do not average across differing scopes'). Missing an explicit statement of when this tool is the wrong choice, so it falls short of a full 5.

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