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

Annotations already convey readOnly, idempotent, and non-destructive behavior. The description adds the useful behavior that authentication is required, and clarifies the account-scoped nature of the data, providing context beyond the structured 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?

Two compact sentences front-load the purpose, state the output, and provide concrete use cases and an authentication note. There is no filler or redundant explanation.

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, read-only list tool, the description is complete: it names the resource, the output, the primary use cases, and the authentication requirement. The absence of an output schema is mitigated because the description already states what is returned.

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?

The schema covers the single optional sessionKey parameter with a 100% description coverage, so the description does not need to add parameter details. The mention of authentication is relevant but does not materially enhance the schema-provided semantics.

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 verb 'List', the resource 'SSH keys stored on your account', and the specific output ('ids and SHA256 fingerprints'). It distinguishes this read-only listing tool from sibling tools like addSshKey and deleteSshKey by emphasizing account-scoped retrieval.

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 explicitly tells when to use the tool: to check whether a key is already stored and to obtain ids for use with orderVps or buildVpsInstance. It provides clear context and downstream integration, though it does not explicitly contrast with add/delete SSH key tools.

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