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

The readOnlyHint annotation already declares this is a safe read operation. The description adds the REST method (GET) and path, which is minor contextual value beyond the annotation. It does not describe error behavior, response format, or authentication, but the annotation reduces the burden. No contradiction with annotations.

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?

The description is two short sentences, directly states the purpose, and includes the REST reference. There is no wasted verbiage, making it easy to parse quickly.

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 retrieval tool with one parameter, a read-only annotation, and no output schema. The description sufficiently conveys what the tool does and how to invoke it. No additional context is necessary.

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% for the single 'id' parameter with its own description. The tool description says 'by id' and shows the URL placeholder '{id}', which aligns with the schema but adds no new semantic detail. Baseline of 3 is appropriate.

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 clearly states the tool's function: 'Get a single sale by id.' It uses a specific verb ('Get') and resource ('sale'), and the phrase 'single' distinguishes it from listing tools like gumroad_list_sales. The REST endpoint adds precision.

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?

The description provides clear context: this tool is for fetching a single sale by its id. However, it does not explicitly name alternatives like gumroad_list_sales for retrieving multiple sales, so it lacks explicit when-not-to-use guidance. The 'single' keyword implies the distinction.

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