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

Annotations already cover the read-only, idempotent, non-destructive safety profile, and the description adds genuinely non-obvious behavior: inspection does not extend TTL and does not trigger single-use 'burn' key consumption. Those are exactly the side effects an agent cannot infer from the schema or annotations.

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?

One sentence, front-loaded with the action and then the three non-behaviors, with no filler wording. It is dense but every clause carries distinct information; a brief mention of the returned metadata shape would still be affordable.

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 single-parameter read tool with full safety annotations and no output schema, the description covers the critical semantics well. It leaves the returned metadata fields and the missing-key behavior unexplained, which are the only meaningful gaps remaining.

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 description coverage is 0% and the single 'key' property carries only a pattern, no prose, so the burden falls entirely on the description — which says nothing about the key format or that it identifies the entry being inspected. The parameter name is largely self-evident, keeping this at the minimum-viable baseline rather than lower.

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 (Inspect) and resource (metadata and ETag), and immediately scopes what it does NOT do — read values, renew expiry, consume burn keys — which cleanly separates it from get_key and touch_key. An agent can pick this over its siblings without opening any schema.

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 negative scoping ('without reading values, renewing expiry or consuming burn keys') effectively tells the agent when to choose this instead of a value-returning or TTL-extending call. It falls short of naming the alternative tools explicitly, so the routing is implied rather than spelled out.

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