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

Annotations already flag this as non-idempotent and destructive, but the description adds critical behavior they cannot express: the secret is disclosed exactly once ("returned only now; store it"), it is revocable via Settings → API, and creation is gated on a confirmed owner email. These are the details an agent needs to avoid leaking or mis-timing the key.

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?

Four short clauses ordered by importance: what it is, the one-time-secret caveat, where it lives/is revoked, then the prerequisite. No filler and nothing repeated from the title or schema.

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?

With no output schema, the description correctly covers the essential return semantics (key shown once). The remaining gap is scope defaults for the optional `scopes` parameter, which neither the description nor the schema addresses.

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 coverage is 50%: `name` is documented with an example in the schema, but `scopes` has no description anywhere. The description says nothing about parameters, so it does not compensate for the gap, and it also leaves unanswered what scopes are granted when the optional `scopes` array is omitted.

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 ("Create a long-lived API key") and even the key format prefix (sd_live_…). No sibling tool in the list deals with API keys, so the resource alone discriminates it from the appointment/location/webhook tools.

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?

Gives a clear use case ("for scripts and clients that can't refresh OAuth tokens") and a precondition ("Needs the owner's email confirmed first"). It stops short of naming an alternative mechanism (e.g. the OAuth flow) explicitly, so it is context without full when/when-not routing.

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