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

readOnlyHint=true already covers the safety profile, so the bar is lower. The description nevertheless adds real value by disclosing the payload contents — line items, payments, taxes and totals — which tells an agent what data is available without needing to inspect the response first. No contradictions with the annotation.

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?

Two short sentences with no filler: the payload contents come first, followed by the endpoint. Every clause 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?

For a simple one-parameter read with no output schema, the description covers the essentials by enumerating the returned components. It stops just short of mentioning not-found or error behavior, which is a minor omission.

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 coverage is 100% and the sale_id parameter is already fully documented in the schema, including its pattern and provenance ('from list_sales or search_sales'). The description adds nothing beyond that, which is the expected baseline for a fully documented single parameter.

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 ('One sale by id') plus the scope of what's returned. 'By id' distinguishes it from list_sales and search_sales, which return collections rather than a single sale.

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 implied: fetch a single sale when you have its id. But the description never explicitly says when to prefer this over list_sales or search_sales, nor what happens with an unknown id. The routing hint 'from list_sales or search_sales' lives in the schema, not in the description.

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