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

Annotations already declare destructiveHint=true, so the description needn't restate the safety posture. Beyond that it adds nothing behavioral — no note on what the created namespace contains, side effects, or what is returned; the only extra content is a bare 'POST /v2/apis.createApi' restatement that carries no decision value.

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 first sentence is front-loaded and efficient. The second sentence restates the HTTP endpoint, which adds nothing an agent needs and dilutes the definition's brevity.

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 one-parameter create tool with a fully documented schema and no output schema, the description is adequate to invoke it correctly. It is thin on the return value (e.g., the new API's identifier) and on any creation constraints, leaving modest gaps.

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 fully documents 'name' and the description adds no naming conventions, uniqueness rules, or format constraints. Baseline 3 applies when the schema does all the work.

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 new API namespace') and adds the purpose 'to issue keys under,' which distinguishes it from sibling creators like unkey_create_key and unkey_create_identity. It stops short of explicitly naming those siblings, so it falls just below 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?

The phrase 'to issue keys under' implies this is the prerequisite namespace for key creation, giving an implicit ordering hint. There is no explicit when-to-use vs. when-not-to-use guidance and no mention of alternatives, so this is minimum viable.

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