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

Annotations already establish read-only, idempotent, and non-destructive behavior. The description adds useful behavioral context: it computes tip and total, may use percent or round-up, and returns amounts plus canonical country and calculator URLs. No conflicts with annotations.

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?

One dense, front-loaded sentence covers purpose, calculation mode, and return value highlights without filler. Every clause adds information an agent needs.

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 annotations, full schema coverage, and presence of an output schema, the description supplies enough for safe invocation. A minor gap is that it does not explain how the optional service parameter affects the result or how the percent-vs-round-up mode is selected.

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%, so bill, country, and service already have descriptions. The description adds that country norms drive the calculation and mentions percent or round-up, but it does not otherwise clarify parameter mechanics beyond the schema. Baseline 3 is appropriate.

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 names the action (calculate) and the resource (suggested tip and total), and scopes it to Tipping Rules country norms. It is distinguishable from get_tipping_rules and search_countries by function, though it does not explicitly contrast with them.

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?

It implies this tool is for computing a tip/total for a given bill and country, but provides no explicit conditions about when to prefer it over get_tipping_rules or search_countries. There are no exclusions or alternative routing statements.

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