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

With no annotations provided, the description must disclose behaviors. It states the output unit 'W' and implies a simple calculation, but does not reveal assumptions, limitations, or edge cases (e.g., temperature difference range, heat loss coefficient). This is adequate for a straightforward tool but not rich.

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 three concise sentences: purpose, usage, and a pointer to related tools. It is front-loaded with key information, contains no filler, and every sentence adds value.

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?

For a simple calculation tool with an output schema, the description covers purpose, inputs, output unit, and related resources. It could be more complete by mentioning the formula or assumptions, but it is sufficient for an agent to understand and invoke 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% with descriptions for each parameter. The description enumerates inputs as 'tank L, current temp, target temp' but adds no new meaning beyond the schema. It does not provide units (e.g., liters, °C) or typical values, so it meets the baseline without compensation.

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 clearly states the tool computes aquarium heater wattage from tank volume and target temperature, establishing a specific verb-resource pair. However, it does not explicitly distinguish this tool from sibling aquarium calculators like calculate_aquarium_volume, though it hints at related tools via list_bundles.

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 advises 'Use for aquarium setup,' providing implicit context but no explicit exclusions or alternatives. The mention to see list_bundles for related calculators offers a partial guide but lacks direct comparison with sibling tools.

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