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

Annotations already declare a safe, closed-world, idempotent read. The description adds real context beyond them: results carry a ruble price and a link, availability is constrained to payment from Russia, and fulfilment is performed by a human on the website, which correctly signals that no purchase can be executed through this tool. It does not cover result volume, ranking, or empty-query 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?

Three short sentences, front-loaded with the resource and scope, then examples, then return contents and the fulfilment caveat. Every sentence carries information; only minor fragmentation keeps it from a 5.

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 one-optional-parameter read tool with annotations and no output schema, the description covers scope, result contents, and the human-fulfilment limitation. The main residual gap is behavior with an omitted query (list-all vs. empty result) and its distinction from search_models.

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 the single optional 'query' parameter is documented in the schema with an example. The description adds nothing about the parameter, but with full schema coverage 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 resource and scope: subscriptions to AI services (ChatGPT, Claude, Gemini, Cursor) payable from Russia, returning price in rubles and a link. An agent can tell this is a catalog lookup rather than a model/job/pricing lookup. It does not explicitly contrast with siblings like search_models or get_gateway_prices, which keeps it from a 5.

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 guidance, and no sibling is named as an alternative. Usage is only implied by the resource description; the agent must infer that this is the tool for purchasable subscription offers versus model metadata or gateway pricing.

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