create_volume

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

With no annotations, the description carries the behavioral burden; it does disclose that the operation creates a separately billed persistent resource and returns a name/id. It does not, however, mention permissions, cancellation/deletion, or any other side effects beyond rental, leaving some uncertainty for an agent.

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 sentences convey the resource, billing distinction, and return value with no filler or redundant information.

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 one-parameter creation tool with no output schema, the description covers the key facts: what is created, that it incurs separate billing, and what is returned. It is slightly incomplete only in not giving explicit when-to-use guidance compared with sibling tools.

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 100% and the only parameter, size_gb, is already documented with its default in the input schema. The description adds no parameter-level meaning, so the baseline 3 is appropriate.

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?

The description uses a specific verb ('Rent') and resource ('persistent volume on Vast.ai'), and distinguishes the action from instance creation by noting the volume is billed separately from instances. An agent can immediately tell this tool creates storage rather than listing or launching instances.

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 billing note ('billed separately from instances') implies this is for persistent storage rather than instances, but the description never states when to choose this over alternatives such as create_instance or list_volumes. Selection context is inferred from the resource name rather than explicitly routed.

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