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

No annotations are provided, so the description carries full burden for behavioral transparency. The description only states it computes a bill, implying no side effects, but it does not mention permissions, rate limits, or any behavioral traits. Additionally, it mentions 'fixed fee' and 'variable rate' as inputs, which are not in the actual schema, causing potential confusion.

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 relatively concise, with five sentences covering purpose, usage, inputs, output, and a reference. It is front-loaded with the main action. However, there is some redundancy (e.g., 'Inputs' sentence restates first sentence) and could be tightened.

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 tool with two parameters and an output schema, the description gives essential info but lacks details on tariff bands and how the calculation works. The mention of 'fixed fee' and 'variable rate' not in the schema creates a gap. The reference to list_bundles is helpful. Overall, adequate but not fully complete.

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 schema has 100% description coverage, providing clear descriptions for both parameters. However, the description adds 'fixed fee' and 'variable rate' as inputs, which are not in the schema and may mislead the agent. This introduces confusion beyond what the schema provides, reducing the score.

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 it computes a water bill from cubic meters consumed and tariff bands, specifying the verb and resource. The name itself is specific, and the description adds the context of household budget. However, it does not explicitly distinguish it from other similar calculator tools in the sibling list, but the specificity is sufficient.

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 usage context ('Use for household budget') and suggests looking at 'list_bundles' for related calculators, implying there are alternatives. However, it does not specify when not to use this tool or give clear guidance on selecting this over similar tools.

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