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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds value by specifying what the tool returns (summary, availability, primary source, safety notes) and that it targets only documented features. It does not mention not-found/error behavior, but for a simple read-only getter this is a minor gap.

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?

One sentence with no filler, front-loaded with the verb and object. Every element contributes meaning: the resource, the ID type, and the returned content.

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 single-parameter, read-only, idempotent tool, the description is largely complete: it names the input and the output content. The only notable omission is behavior when the feature ID does not exist, but this is not critical for a simple getter.

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 0%, so the description must compensate. It adds that feature_id is a 'stable feature ID' tied to documented features, which gives some meaning beyond the schema pattern, but it does not explain how to find valid IDs or relate it to list_features.

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 ('Return'), a resource ('one documented Aperture Wallet feature'), and a scope ('by its stable feature ID'), and lists the returned content fields. This clearly distinguishes it from siblings like list_features or get_article.

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 clearly implies the tool is for fetching a single feature when its stable ID is known, and the inclusion of 'one documented feature' contrasts with list_features. However, it does not explicitly name an alternative or state when not to use it.

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