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

readOnlyHint=true already tells the agent this is a safe read, so the description's duty is reduced. It adds only the underlying REST call (GET /payments, query parameters) and nothing about result volume, retention, or whether pagination is required to see everything. Adequate but thin beyond the annotation.

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?

Front-loaded: purpose, then routing, then API trivia. The three short sentences contain little waste, though 'Checkout.com: GET /payments (query parameters)' is implementation detail that contributes marginally to tool selection.

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 simple 3-parameter read tool with full schema coverage and a readOnly annotation, the description covers purpose, the filter, pagination fields via schema, and the richer alternative. No output schema exists, so return-shape omission is acceptable; only the no-reference default is unstated.

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 skip, limit and reference are already fully documented in the schema. The phrase 'match a given reference' only echoes the reference property, adding no format, matching mode, or partial-match semantics. Baseline 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?

States a specific verb (List) + resource (payments) + scope (matching a given reference) in one clause. It also names the sibling it is not, so an agent can distinguish it from checkout_search_payments without opening either schema.

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?

Explicitly routes the agent to checkout_search_payments 'for richer filtering', which is a clear when-to-use signal against an alternative. It stops short of stating the converse (e.g. that it lists all payments when reference is omitted), so behavior in the no-reference case is left to inference.

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