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

The readOnlyHint annotation already carries the safety profile, so the bar is lower, and the description adds a genuinely useful behavioral fact: the secret key value is not retrievable, which preempts an agent attempt to extract credentials. It does not address pagination or result ordering, but with zero parameters there is little else to disclose.

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 scope and return fields, then the constraint. Every clause earns its place and there is no filler or repetition of the title.

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 zero-parameter read with a safety annotation and no output schema, the description covers everything needed: what it returns and the one limitation that could cause an agent error. No call-relevant information is absent.

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 tool takes no parameters, so the baseline is 4 and there is no parameter meaning for the description to add. Nothing here is missing or misleading on that front.

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?

A concrete verb (list) plus resource (the account's API keys), and it names what each row exposes: name, prefix, and last-used time. That is unmistakably distinct from the mutating siblings create_api_key and revoke_api_key, so an agent needs no schema inspection to route correctly.

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?

There is no explicit when-to-use or when-not-to-use guidance and no named alternative. Usage is only implied: it is the read path for inspecting key metadata, and the note that keys cannot be read back implicitly tells the agent not to use this to retrieve secrets.

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