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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds no additional behavioral context such as output format, performance characteristics, or constraints beyond the vague 'machine-readable assumptions'. It does not contradict the annotations, but it also does not enrich them meaningfully.

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?

The description is a single, concise sentence with no fluff. It is front-loaded with the core action and resource. However, its brevity sacrifices essential detail, so while it is structurally efficient, it is not fully informative.

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?

Given the tool's complexity (nested object parameters, no schema descriptions, no output schema) and the absence of any usage guidance, the description is far from complete. An agent would not know how to format options, what the comparison entails, or what to expect as a result. The description fails to compensate for the lack of structured detail.

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% and the description does not explain the structure or expected content of option_a and option_b. It only refers to them as 'two preliminary heating options', which is insufficient for an agent to construct valid inputs. The schema shows they are objects with additionalProperties, but no required fields or examples are given.

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 ('compare') and resource ('two preliminary heating options'), and adds 'using machine-readable assumptions' which hints at the input format. It is distinguishable from sibling tools that perform individual calculations (e.g., heat_loss_total, heating_energy_cost). However, it does not specify what the comparison produces or what 'preliminary' implies.

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?

No guidance is provided on when to use this tool versus its siblings. There is no mention of prerequisites, alternatives, or conditions that would lead an agent to choose this tool over other heating-related tools. The description is silent on usage context.

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