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

With no annotations provided, the description carries the full burden of disclosure. It states it returns liters per day and glass count, but does not reveal the underlying formula, assumptions, or limitations. This is adequate for a simple calculator but lacks depth.

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 extremely concise, using only two short sentences. Every phrase adds value: the verb, inputs, usage context, and cross-reference to related calculators. No wasted words.

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 simplicity (3 parameters, output schema exists), the description is largely complete. It covers purpose, inputs, outputs, and use case. Missing details like formula or assumptions are not critical for a common health calculator, and the output schema handles return structure.

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 input schema has 100% coverage with descriptions for each parameter. The description reiterates the inputs with added context (units for weight, enum values for climate) and mentions the outputs, adding value beyond the schema. Baseline 3 is elevated due to this additional context.

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's purpose with a specific verb ('Compute recommended daily water intake in liters') and specifies the inputs (weight, activity, climate). It distinguishes itself from numerous sibling calculator tools by focusing on water intake and mentioning related 'sante' calculators 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 provides a clear use case ('Use for hydration planning') and directs users to list_bundles for related calculators, offering some guidance on alternatives. However, it does not explicitly state when not to use this tool or exclude other scenarios.

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