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

Annotations already declare readOnlyHint=true, so the bar is lower, but the description adds real value by pre-empting confusion over the POST verb: 'this is a READ — it queries, it does not mutate.' It also discloses the underlying endpoint (POST /payments/search). It stops short of covering pagination behavior or result-set limits beyond the schema.

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 purpose before the read-only clarification and the parameter hint. No filler, though the endpoint reference is arguably redundant for an agent that only needs the tool name.

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?

Adequate for a filter-based search with 100% schema coverage and no required params, and the read-only clarification closes the main behavioral gap. However, with nested filter/pagination objects and no output schema, the description does not sketch the shape of returned results, which an agent would need to chain calls.

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%, so the baseline is 3. The description names the two parameter families ('query' filter object and 'paging fields') but adds no syntax, format, or field-level detail beyond what the schema already documents.

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 and resource ('Search payments') plus the mechanism ('flexible query filters'), which is enough for an agent to grasp what it does. It does not, however, differentiate itself from the sibling checkout_list_payments, leaving the search-vs-list distinction to inference.

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?

The description says to 'Pass a `query` filter object and/or paging fields', which implies usage (use it when you have filter criteria) but never states when to choose this over checkout_list_payments or checkout_get_payment. No prerequisites or exclusions are given.

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