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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds one genuinely useful behavioral fact beyond that — results are ordered "newest first" — but says nothing about pagination defaults/caps or whether refunds, tips, or pending claims are included.

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 compact sentence with zero filler, and the key scope constraint is front-loaded before the sort order. It is efficient without being cryptic, though it leaves no room for the usage or pagination context that would help.

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 low-complexity, two-parameter read-only list tool this is close to adequate, and the absent output schema means return values needn't be explained. The remaining gap is pagination behavior and the boundary against list_payments/list_client_invoices, which an agent must guess.

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 coverage is only 50%: clientId is documented in the schema (with a pointer to list_clients), while the nested pagination object has no field-level descriptions anywhere. The description contributes no parameter meaning at all, so the undocumented half stays undocumented.

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 resource and scope: payments belonging to exactly one client, and clarifies directionality with "(to this coach)", which separates it from list_payments and list_organization_payments. It never names a sibling explicitly, so an agent must infer the distinction from scope wording alone.

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 scoping phrase "one client" implies when this tool fits (per-client payment history) rather than the broad list_payments, but there is no explicit when-to-use statement, no prerequisites, and no named alternative to route away from.

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