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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that by disclosing the returned content and framing it as equivalent to a UI surface ('same numbers as Reports → Financial Summary'), which helps the agent trust and interpret the output. It doesn't cover auth requirements or pagination/limits, but with annotations carrying safety this is solid.

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 return contents, then routes the agent to the sibling. A few phrases are stylistic ('what lands in my bank'), but every sentence carries either scope, return content, or routing information, so it earns its length.

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, the description carries the burden of describing returns, and it does so by enumerating every headline figure and the settlement split. Combined with annotations covering safety and a fully documented schema, an agent has everything needed to call it 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 schema already documents startDate, endDate, outlets, and stations with format and inclusivity rules. The description adds nothing parameter-specific beyond implying a date range, so the baseline 3 applies.

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 ('headline money report for a date range'), enumerates the exact figures returned (gross sales, discounts, refunds, fees, tax, tips, net sales, settlement split), and explicitly distinguishes itself from get_sales_breakdown. An agent can identify and differentiate this tool without 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?

Gives an explicit selection rule: 'Start here for any "how did the business do" question, and only reach for get_sales_breakdown when the merchant wants the individual orders behind these totals.' Names the alternative and the condition that routes to it, plus example user questions that map to it.

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