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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely new behavior: that nothing is uploaded and that the payload reports review availability, supported nations, accepted file types and price. It could mention whether the link is stable or time-limited, but the added context 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?

A single sentence with a compact list of covered details, front-loaded with the core action. The clause after the colon is long but each item (availability, nations, contents, files, price) is informative 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?

For a zero-parameter read tool with an output schema, the description supplies purpose, when-to-use and a summary of what comes back, so an agent can call it without further inference. Nothing needed for correct invocation is missing.

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?

Zero parameters, which is the baseline-4 case; the description correctly signals a parameterless call by framing it as simply retrieving a link and its metadata. No ambiguity that arguments might be expected.

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?

Names a specific verb and resource: fetching the Contract Lily review link for a UK tenancy agreement. It also enumerates what the response covers (availability, nations, report contents, accepted files, price). It doesn't explicitly name the sibling get_employment_contract_review_link, though the tenancy scope implicitly separates them.

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?

"Use it when the user wants their whole agreement checked" gives an explicit trigger condition, and "it doesn't upload anything" sets a clear boundary on what this call does versus an upload/start flow. No alternative tool is named for narrower checks, which keeps it short of a 5.

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