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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral guarantee — that catalog-missing prices are omitted rather than fabricated — which prevents an agent from misreading an absent price as zero. It says nothing about return shape or whether results are sorted, so it sits just at adequate.

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?

Three short sentences with zero filler, front-loading the action and scope before the filter note and the omission caveat. Every sentence carries distinct 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?

There is no output schema, and the description does not describe what a returned price record contains (per-provider or per-resolution granularity). For a simple read tool with fully documented parameters it is close to sufficient, but the return surface remains unstated.

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%, so the schema already documents all three parameters in detail, including examples. The description adds only that provider and resolution are optional filters and that lookup is constrained to a single model, which barely extends the schema. Baseline 3 applies when the schema does the heavy lifting.

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 ('List current VidFare prices') and scopes it to one model, which separates it from list_models and cheapest_options. It does not explicitly name which sibling to use for aggregate or cheapest-price queries, so differentiation is implied rather than stated.

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 description clarifies that provider and resolution are optional filters, which implies the lookup pattern. It gives no guidance on when to prefer this over cheapest_options or estimate_cost, nor any prerequisite or exclusion.

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