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

Annotations only cover the safety profile (readOnly=false, destructive=false, idempotent=false). The description adds a genuinely important behavior not in structured data: the secret is returned exactly once and must be stored immediately. It still says nothing about required permissions or how many keys can exist.

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, no filler. The core action leads and the critical one-time-secret warning follows immediately; every clause earns its place.

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 creation tool with no output schema, the description covers the most failure-prone aspect (the secret is shown once). It is close to complete, though it omits what the created key can do (scopes/permissions) and that the key lives until revoked.

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?

With a single parameter at 100% schema description coverage, the schema already documents "name" with an example label. The description adds no syntax, format, or constraint detail beyond that, so the baseline 3 applies.

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+resource ("Create an API key") and adds scope ("for another agent or script"), which clearly separates it from the sibling read/list tools. It doesn't explicitly name the alternatives (list_api_keys, revoke_api_key), but the action is unambiguous.

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?

"For another agent or script" implies the intended usage context, but there is no explicit when-to-use vs when-not, no prerequisites (e.g. owner verification), and no mention of the sibling revoke_api_key for lifecycle management. Usage is inferred rather than stated.

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