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

Goes well beyond the readOnlyHint annotation by disclosing that it is a dry run that executes the same validation set as create_vm, that nothing is created, and that it requires the vms.create scope. It omits edge behavior such as whether a failed check surfaces as would_succeed=false or an error, and whether the returned price is guaranteed at creation time.

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 dense sentence for behavior plus two short clauses for sequencing and scope; nothing is padded and the key fact (no creation) is front-loaded.

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 output schema, the description usefully enumerates the four returned values, and the scope note covers the authorization question. It could still say what a false would_succeed looks like or whether the estimate expires, but for an agent deciding to call it, this is close to sufficient.

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% and each of the 10 parameters is documented with slugs, cross-references to list_* tools, and behavioral notes (billing, ipv4, private_only). The description adds nothing parameter-specific, so the baseline 3 applies.

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 ('runs every check of create_vm and prices it') and immediately disambiguates from the sibling create_vm by saying it creates nothing. The list of returned values (would_succeed, hourly rate, monthly price, credit required) makes the output contract tangible.

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?

'Call it before create_vm' gives an explicit sequencing rule that an agent can act on. There is no explicit when-not or named alternative for the no-estimate case, but the pairing with create_vm leaves little ambiguity.

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