Cash counter

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

Annotations already declare read-only, idempotent, closed-world behavior, so the safety profile is covered. The description adds real substance beyond that: exact integer arithmetic with no float error, currency-specific decimal rules (JOD 3 decimals/fils, custom 0/2/3), and the return contents including over/short against an expected amount — meaningful for a tool with no output schema.

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?

Front-loaded with the core purpose and technique, then input forms, then return values, then the list mode — a logical order with little waste. It is one very long compound sentence plus a trailing web URL that adds no value to an agent, which keeps it short of a 5.

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 read-only tool with a nested counts array, six optional parameters and no output schema, the description covers input formats, currency/precision handling, the list mode and the returned totals/over-short. It is silent on edge behavior — e.g. an invalid denomination for a currency, mixed note/coin disambiguation beyond the schema's kind field, or what an empty counts array returns.

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 the baseline is 3 and the schema already documents every field. The description still adds usable semantics: denominations may be given by value (50, 0.25) or by label ('50 JD', '¼ dinar'), and it explains what 'expected' produces (over/short) rather than just restating the field name.

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 specific verb and resource ('Count a cash drawer by denomination') plus the defining technique ('exact integer maths, no float errors'), which separates it from generic calculators like calc_expression or calc_split_bill. It also enumerates supported currencies and the custom-currency option, so an agent knows exactly what domain this covers before opening the 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?

Usage context is clear: give counts per denomination, and set list=true to discover a currency's denominations first — a sensible discovery-then-count flow. It does not explicitly rule out alternatives (e.g. when to prefer calc_expression for a plain arithmetic total, or calc_split_bill for splitting), so it stops short of full when/when-not guidance.

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