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

Annotations already declare readOnlyHint and non-destructive, so the 'Read only' clause is redundant. The genuinely additive part is disclosing the returned fields, which matters because there is no output schema. It stops short of covering not-found behavior or permission requirements.

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 no filler, resource front-loaded. The phrasing is slightly clipped ('One payment: ...') and leaves the verb implicit, trading a bit of clarity for brevity.

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 single-record read with full schema coverage and read-only annotations, the description covers what comes back — which is the main gap given no output schema. Only edge behavior (missing payment, receipt format) is left 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?

With one parameter at 100% schema coverage, the schema already documents paymentId including its provenance ('Id from list_payments'). The description adds no format, range, or lookup guidance beyond that, so 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?

The description makes clear that this returns a single payment and enumerates the fields the agent will get back (amount, due date, status, method, receipt), which distinguishes it from the bulk list_payments sibling. The retrieval verb is only implied by the name/title rather than stated, and no sibling is named explicitly.

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?

There is no when-to-use or when-not-to-use guidance beyond the implicit 'one payment' scope. The alternative (list_payments, list_student_payments, get_statement) is never named; the only routing hint is inside the parameter schema ('Id from list_payments'), not in the description.

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