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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so safety is covered. The description adds real behavioral value beyond that: it discloses that price rows are returned with the source page that states them and that data carries a 'when it was checked' freshness stamp, which tells an agent how to cite and trust results. It stops short of describing not-found behavior or payload size.

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?

It is a single front-loaded sentence with the core noun phrase first and the returned fields enumerated afterward; no sentence is wasted. It is long, but the length comes from a purposeful field list rather than filler.

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 only one parameter, full schema coverage, and annotations, the main remaining burden is describing the return payload, which the description does via an enumerated field list (prices, insurance, Medicare/Medicaid, prescribing, formats, ages, matching/switching, last-checked). Only edge cases such as an unknown service name or missing coverage are unaddressed.

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 schema already documents that the parameter accepts a name or onlinetherapy.me slug with an example. The description only reinforces the singular constraint ('one service') and adds a few more real-world name examples, which is marginal added meaning over the structured field.

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 the exact resource (one online therapy service on OnlineTherapy.me) and enumerates the record types returned, with concrete entity examples like BetterHelp and Talkspace. It is clearly a single-record detail fetch, distinguishable from siblings such as compare_online_therapy_services and search_online_therapy_services, though it never explicitly names those siblings to sharpen the contrast.

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 tool returns detail for one already-identified service, and the phrasing 'everything ... records about one service' signals a full-detail lookup versus a list/search. However, there is no explicit guidance on when to prefer it over search_online_therapy_services or compare_online_therapy_services, and no note about needing a valid service name/slug first.

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