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

Annotations already cover the safety profile (readOnly=true, idempotent=true, closed-world), so the description's job is to explain what comes back, and it does: per-service self-pay figures plus median, lowest, highest, count at or under $100, insured ranges, and source page per figure. It stops short of saying how many services are covered or whether services lacking published prices are omitted from the output.

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?

A single sentence, front-loaded with the core object ('the self-pay price of one regular session'), with the metric list tucked into a parenthetical rather than scattered. It is dense but every clause names a real output field; only the trailing 'each service's figure with its source page' clause could be tightened.

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 input parameters and no output schema, the description carries the full burden of describing results, and it enumerates the aggregate and per-service fields adequately. The main remaining gap is output shape and volume: it does not say whether results are a table, how many services appear, or how services without published prices are handled.

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, which is the baseline-4 case; there is no argument to explain. The description correctly implies a parameterless, whole-catalog call by not referencing any filters, so nothing is left ambiguous on the input side.

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 names a specific resource (self-pay per-session prices) and a specific scope (every service that publishes one), and enumerates the exact aggregates produced: median, lowest, highest, count at or under $100. That clearly separates it from the per-service siblings such as get_online_therapy_service and search_online_therapy_services.

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 implied rather than stated: the phrase 'at every service that publishes one' signals a breadth-first census, which contrasts implicitly with the per-service siblings. However, no sibling is named and there are no explicit when-to-use or when-not-to-use conditions, so the agent has to infer that this is the aggregate-first choice.

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