List hypervisors

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered; the description still earns credit by disclosing the elevated role requirement and explaining that a forbidden response means a missing role rather than an empty result. It also states that the call is not paged, which is real behavioral context beyond the 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?

Three short sentences with the core purpose front-loaded and no filler. The final sentence about filters is the weakest — it is short but points at capability that does not exist in the schema, so it does not fully earn 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?

An output schema exists, so return-value detail is unnecessary, and the description covers the two non-obvious operational facts an agent needs: the privilege requirement and the absence of pagination. The unresolved gap is that "narrow with filters" implies filtering options that the tool does not offer.

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 100%, so both parameters are already fully documented in the schema and the baseline applies. The description's only nod to parameters is "narrow with filters," which adds no meaning and is mildly inconsistent with a schema that exposes no filter beyond limit and project_id.

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 — "List Nova hypervisors" — plus what the result carries (state and capacity), which distinguishes it from generic siblings like list_services or list_compute_services. It stops short of explicitly contrasting with those nearest neighbors, so the differentiation is implied rather than stated.

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 description gives a prerequisite and an error-decoding rule, but never says when to choose this over list_compute_services or the per-resource get_* tools. Usage context is implied at best, and "narrow with filters" points at filtering that the schema barely supports (only limit and project_id).

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