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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and openWorldHint=false, so the safety profile is covered. The description adds domain behavior beyond that: the calculation is country-custom driven, with concrete per-country rule examples, and it returns both a recommended tip and a total. It does not need to explain return shape further since an output schema exists.

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 short sentences, front-loaded with the purpose and country-custom examples before the input/return summary. Slightly telegraphic ("Inputs: bill, country") but no wasted prose; the final cross-reference sentence is marginal but cheap.

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?

Annotations cover the safety profile and an output schema covers the return shape, so the description only needs to establish scope, which it does. A minor residual gap is behavior for countries outside the enum or non-restaurant tipping contexts, which the agent must infer.

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% and the country enum is fully enumerated in the schema, so the schema already carries parameter meaning. The description's "Inputs: bill, country" merely restates the required fields and adds no constraints, units, or currency semantics beyond the schema.

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?

States a concrete verb (Compute), resource (restaurant tip) and the distinguishing scope: local custom by country, with worked examples (US 18-22%, FR included, JP no tip). This separates it cleanly from the generic calculate_tip and calculate_tip_split siblings without the agent needing to open any schema.

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?

"Use when traveling" implies the context, but there is no explicit contrast with calculate_tip or calculate_tip_split and no when-not condition. The list_bundles pointer is navigation for related calculators, not guidance on choosing this tool over its near-identical siblings.

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