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

With no annotations, the description shoulders the full burden. It reveals the admin requirement, that secret keys are never shown again, that 'current' and 'scopes' are relative to the calling key, and the special 'original' key ID. It does not discuss error cases or rate limits, but coverage is strong for a read-only list operation.

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 dense and front-loaded: the purpose statement comes first, followed by compact field enumeration and key constraints. The trailing 'Same shape as GET /v1/keys' and 'Free' are useful but slightly redundant given the output schema, costing a point.

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 list operation, the description covers the essential semantics: admin requirement, key ID schema, per-key access fields, and the calling-key relationship. The only notable omission is explicit guidance on the api_key parameter itself, but the rich output schema and output-shape mention reduce the gap.

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 sole api_key parameter has no schema description, and the description never names it directly. It does indirectly clarify its role via 'current (true for the key making this call)' and 'scopes: the calling key's,' which tells the caller that the supplied key determines the response. That partial compensation warrants a middle score rather than lower.

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 opens with 'Your API keys and what each may do,' which clearly identifies the resource and the listing intent, and enumerates output fields. It does not explicitly use the verb 'list' or call out sibling alternatives, so it stops short of a 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?

It gives useful context ('Needs admin', 'Free', 'Same shape as GET /v1/keys') and the output shape implies this is the read-only view of keys. However, it never states when to prefer this over create_key/revoke_key or other siblings, leaving the comparison implicit.

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