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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely non-obvious data semantics: provider min input/output prices are independent minima that may come from different models. That is real context beyond structured fields, though nothing is said about freshness or pagination.

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 tight sentences, zero filler. The payload contents are front-loaded and the pricing caveat with its alternative follows immediately, so the agent reads the most important routing information first.

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?

An output schema exists, so return values need no explanation, and the description still flags the key interpretation pitfall about independent minima. It is complete enough to call safely; only minor gaps remain (e.g., what 'roles' denote, staleness of counts).

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?

The tool takes zero parameters, so there is nothing to disambiguate and the baseline is 4. The description correctly spends its budget describing output content instead of parameter syntax.

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 (discover/list) and resource (providers), and enumerates the payload contents: accepted provider slugs, roles, and comparable model/offer counts. It also differentiates itself from offer_compare by name, so an agent can distinguish it from siblings without opening schemas.

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?

Gives a clear conditional redirect: use offer_compare for an actual quote, implying provider_list is for discovery/comparison rather than pricing decisions. It doesn't cover when to prefer it over benchmark_list or catalog_search, so it falls short of full alternative coverage.

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