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

Annotations already declare this a read-only, idempotent, open-world operation, so safety is covered. The description adds genuine behavioral detail on top: the two pricing modes (fixed per-call vs. per-token), the conditional cost estimate when a model and token counts are supplied, and the minimum charge per rail. It omits auth/rate-limit or error behavior, but for a read-only lookup this is solid.

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 dense sentences with no filler, and the core return content leads. The jargon ('routes', 'rails', 'brief') is compressed to the point of mild ambiguity, which slightly undercuts the structure.

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, so the description must convey the return shape, and it mostly does (price fields, optional estimate, minimum charge per rail). It leaves unresolved what an all-defaults call returns, what 'routes' and 'rails' denote, and how it differs from omniprovider_get_quote — gaps that matter for a 3-param tool with zero required inputs.

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 only 33% (just `model` is documented), so the description carries extra burden. It partially compensates by explaining that `model` plus input/output token counts together unlock the estimated cost, but it never clarifies token units/counting, whether the two token params are meant to be used together, or limits beyond the schema's max values.

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?

It states a specific verb and resource ('Returns prices') and enumerates what pricing data is available: fixed per-call prices for the nano/small/brief routes and per-token catalog prices. That is well beyond a restatement of the name. It does not, however, distinguish itself from sibling omniprovider_get_quote, which plausibly also returns cost figures.

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?

Usage is only implied: the agent can infer that supplying a model plus token counts triggers a cost estimate, while omitting them yields raw prices. There is no explicit when-to-use, no exclusion conditions, and no routing to omniprovider_get_quote or omniprovider_list_models despite the obvious overlap.

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