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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds genuine behavioral detail beyond them: the result content (totals per register and day), the pagination mechanism ('Page with next_query'), and the underlying endpoint — useful since there is 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?

Three short clauses: what it returns, how to filter, how to page, plus the route. Front-loaded and free of filler; every sentence earns its place.

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?

With no output schema and six optional params, the description covers the returned data shape, filtering and paging well. It is slightly thin on the temporal dimension — the report is 'per day' yet nothing says how days/periods are selected or defaulted — but otherwise enough to call the tool correctly.

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%, so the baseline is 3. The description names the branch/register/staff filters and next_query but adds no semantics the schema lacks (the schema already explains next_query carries the filters and that the other arguments are then ignored), and the free-text 'query' parameter is never mentioned.

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 ('List cash-register closings') and adds the synonyms balances / Z-reports plus what the payload contains ('totals per register and day'). That distinguishes it clearly from siblings like tillhub_list_registers (registers themselves) or tillhub_transactions_report.

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?

'Filter by branch, register or staff' gives context for narrowing results, but there is no statement of when to pick this over tillhub_revenue_sum, tillhub_sales_aggregate or tillhub_transactions_report, and no prerequisites or exclusions. Usage is implied rather than instructed.

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