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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds one meaningful behavioral fact — revenue is based on paid invoices only — but says nothing about timezone/date-boundary handling, whether amounts are tax-inclusive, or how the multi-currency breakdown is expressed.

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 front-loaded sentence that names the measurement, scope, grouping options and output dimension without padding. Every clause carries 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?

For a simple three-parameter read-only report, the description covers what is measured, over what window, and how results are shaped (grouped by period, split by currency), which partly compensates for the missing output schema. Remaining gaps — date-boundary/timezone behavior and the exact return structure — are minor for this tool's complexity.

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%, including ISO date formats and the groupBy enum with its auto-detect fallback, so the baseline is 3. The description restates the grouping and currency dimensions but adds no syntax or format detail 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?

The description gives a specific verb and resource ('Get paid-invoice revenue') plus its slicing dimensions (date range, grouping granularity, currency breakdown). The phrase 'paid-invoice revenue' implicitly separates it from get_expense_report and get_business_overview, though no sibling is named explicitly.

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 is only implied: the word 'paid-invoice' signals that only paid invoices are counted as revenue, which steers the agent away from unpaid/draft data. There is no explicit when-to-use or when-not-to-use guidance versus the other report tools in the catalog.

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