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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description earns credit for adding return-shape behavior not in the annotations: ordering ('oldest first') and the three row types (item sale, payout, reversal), plus the API-key access requirement. It doesn't note pagination or output limits, which keeps it from a 5.

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?

Purpose and scope lead the sentence, followed by return semantics, the alternative tool, and the auth prerequisite — every clause carries information. There is no filler or restatement of the tool name.

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?

This is a simple two-parameter read tool with no output schema, and the description compensates by describing what each returned line represents and the sort order. Combined with the annotation-covered safety profile and the auth note, nothing an agent needs to call it correctly is missing.

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 both 'since' and 'until' are already documented with formats and defaults; the description only references the date range generically. Baseline 3 is correct when the schema does the heavy lifting and the description adds no syntax or format detail.

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 states a specific verb and resource ('sales line items for a date range') plus the granularity ('each line is the sale of an item, a payout or a sale reversal') and the primary field returned ('net amount'). It explicitly names the sibling it is not — export_sales_report — so an agent can distinguish it without opening a 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?

It names the alternative tool and the exact condition that selects it ('Use export_sales_report for the revenue summary or the payout statement'), and adds an authentication prerequisite ('Needs the user's Cotlet API key with access to this app'). Both when-to-use and the required credential are stated, leaving little to inference.

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