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

Annotations already declare readOnlyHint=true, but the description adds a real behavioral trait: the check exercises the root key, so the agent knows this tool validates credentials and requires elevated auth. It does not describe failure signaling or return format, keeping it short of a 5.

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?

Three short sentences, purpose front-loaded before the endpoint metadata. Every sentence carries information (what it does, what it validates, its unique position in the API), with no filler.

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 parameters, no output schema, and readOnlyHint already covering safety, the description covers nearly everything an agent needs. The one gap is that it never says what a healthy or failed response looks like, which matters slightly more given the absent output schema.

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 zero parameters, so the baseline of 4 applies; there is no parameter surface for the description to clarify or omit.

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: verifying the Unkey API is reachable and that the root key authenticates. No sibling among the 19 tools overlaps with a health/liveness probe, so the agent can distinguish it immediately.

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 line 'The only GET in the v2 surface' implies this is a diagnostic probe, but the description never says when to call it (e.g., before a batch of writes, after credential rotation) or what to do on failure. Usage is implied rather than stated, though there are no competing alternatives to route away from.

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