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

The readOnlyHint=true annotation already establishes the safety profile, so the bar is lower. The description adds minimal behavioral context beyond that: it identifies the underlying HTTP surface (GET /payments with query parameters) but says nothing about result ordering, default page size, or how results behave when reference is omitted. Adequate, not rich.

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 the purpose and ending with the disambiguation hint, which is the right ordering. The 'Checkout.com: GET /payments (query parameters)' clause is mildly redundant for an agent but plausibly useful for tracing the underlying API contract.

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 three-parameter read-only list tool with no output schema and fully documented parameters, the description covers purpose, filter scope, and the alternative tool. Only minor gaps remain: no statement about result shape or how pagination behaves when the payment set is large.

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 documented in the schema, which sets the baseline at 3. The description's 'match a given reference' restates the reference parameter rather than adding syntax or matching semantics (exact vs partial match) beyond the schema.

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 ('List your business's payments') plus the scoping filter ('that match a given reference'), and explicitly names the sibling it is not (checkout_search_payments). An agent can distinguish this from checkout_search_payments and checkout_get_payment without opening a 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?

Gives explicit routing guidance: use checkout_search_payments when richer filtering is needed, which cleanly separates it from the sibling. It does not spell out when this tool should NOT be used (e.g., when a single payment ID is already known and checkout_get_payment would be better), so it stops short of full when/when-not coverage.

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