Cash register

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds only "with totals," hinting that aggregated figures are returned — mildly useful context, but nothing about error behavior when a register is not found or what the totals comprise.

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?

A single short sentence with no filler, but it is terse to the point of under-specification rather than efficient density. There is no front-loaded verb or scope statement to anchor the agent.

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?

A two-parameter, single-resource read with fully documented params and rich annotations is simple enough that the definition is barely adequate. With no output schema, the phrase "with totals" is the only hint at return content and remains unelaborated.

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%, with registerId and fresh both documented in the schema, so the baseline of 3 applies. The description adds nothing about the meaning of fresh (cache bypass) or the registerId format beyond what the schema already states.

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?

"One cash register with totals" identifies the resource and signals a single-item scope, implicitly contrasting with the plural sibling cash_registers. However, there is no verb and no explicit statement that this retrieves a register, so the agent must infer read semantics from the annotations rather than the text.

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 word "One" hints at a single-record lookup versus the cash_registers list, but no when-to-use condition, prerequisite, or alternative is named. With siblings like cash_registers and cash_register_operations in the set, the agent gets only weak routing signal.

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