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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so safety is covered. The description goes beyond them by disclosing what the response actually contains, including a computed cost projection for a typical call, which is genuine behavioral value. It omits what happens for an unknown model ID, a minor gap.

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?

A single front-loaded sentence with no filler; the core purpose comes first and the payload contents follow as a compact list. Slightly elliptical phrasing like 'what it supports' and 'context' costs a little precision but nothing is wasted.

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 three-parameter read-only tool with no output schema, the description usefully stands in for the missing return-value documentation by enumerating the fields returned. What remains unstated is the discovery path for a valid model ID and error behavior on an invalid one.

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 all three parameters are documented in the schema, including defaults and an example model ID. The description's phrase 'what a call of a given size would cost' reinforces why tokens_in/tokens_out exist, but adds no syntax or constraint detail beyond the schema, so the baseline of 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?

The description states a specific verb+resource: retrieve one model's detail, enumerating what that detail contains (prices, context window, capabilities, cost for a given call size). This clearly contrasts with a bulk listing, though it never names list_models as the discovery counterpart, so the sibling differentiation is only implied by 'One model.'

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?

There is no explicit when-to-use or when-not-to-use guidance and no named alternative. An agent must infer that list_models is the way to discover a model ID before calling this, and that this tool is for deep-diving a single known model. The singular framing hints at usage but states nothing.

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