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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the required permission scope (vms.read), which is real value, but says nothing about pagination behavior despite a cursor parameter, nor whether the result is complete or truncated.

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, front-loaded fragments with zero padding. It is efficient, though the sentence-fragment style leaves the verb implicit.

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 five optional filter parameters, no output schema, and 40% schema coverage, the description needed to explain filtering and pagination. It partially compensates for the missing output schema by naming returned fields, but leaves the agent guessing about how to narrow results or page through them.

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 coverage is only 40%: cursor and status are documented, while limit, region, and billing are not. The description never mentions filtering at all, and by naming 'status' and 'billing' as returned fields it actively blurs the line with the identically named filter parameters.

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?

Names the resource (the account's machines) and what each entry carries (status, addresses, billing), so an agent knows this is an account-wide VM listing. It does not distinguish itself from get_vm or list_vm_actions, which is the only thing keeping it from 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?

No statement of when to use this versus get_vm, list_vm_actions, or list_regions, and no guidance on whether filters are expected. The 'Scope: vms.read' line is a permission prerequisite rather than usage guidance.

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