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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the REST endpoint mapping (GET /v2/subscribers/{id}), which is mild context. It doesn't disclose response shape, not-found behavior, or auth requirements beyond what annotations imply.

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, front-loaded with the action and scope. The REST endpoint line is useful but arguably redundant given the tool name prefix 'gumroad_'.

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 single-resource read with full schema coverage and readOnly annotation, this is minimally adequate. It lacks return value description, which would help since there's no output schema, and no error/edge-case notes.

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% and there is only one parameter, so the schema fully documents 'id'. The description restates 'by id' without adding format, constraints, or examples. Baseline 3 for high schema coverage.

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 ('Get a single subscriber by id'), which distinguishes it from the list variant. It doesn't explicitly contrast with sibling gumroad_list_subscribers other than the word 'single', so it falls short of 5.

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?

No when-to-use guidance, no mention of alternatives like gumroad_list_subscribers, and no prerequisites or auth notes. The 'by id' phrasing implies it needs an id, but that's already in the schema.

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