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

Annotations already cover read-only/idempotent/non-destructive, so the bar is lower, and the description adds real context: the credit-to-dollar conversion, the meaning of the unit values (per_generation, per_second, usage), and variant-per-resolution behavior. This explains what the returned numbers mean, though it omits any pagination or rate-limit behavior.

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?

Dense but front-loaded: it leads with the core action and pricing, then defines units. The pricing.json cross-reference earns its place as a provenance note. Minor density but no wasted sentences.

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 bears the burden of explaining returns and does so reasonably for a simple list tool by clarifying units and variants. Combined with the fully-covered input schema and safety annotations, an agent has enough to call it correctly.

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 sole 'type' parameter is fully documented in the schema (including enums and 'Omit for all'). The description adds no parameter-specific detail, so the schema-vs-description baseline of 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?

States a specific verb+resource (list models) and enriches it with what the listing contains (standard price in credits, units, variants). It's an unambiguous purpose, but it never differentiates from the sibling get_pricing, which appears to overlap in domain.

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 guidance. The description explains the data returned rather than when to call it or how it differs from get_pricing, leaving the agent to guess whether it should call this or the pricing sibling.

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