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

Annotations already declare readOnlyHint=false, destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful context not in the annotations: that this is bookkeeping-only and does not charge a card, which prevents the agent from mistaking it for a payment processor. It stops short of warning about duplicate submissions or required permissions.

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?

One sentence plus an endpoint, front-loaded with the WRITE classification and the key caveat. Every element earns its place with no filler.

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?

With no output schema, the description need not explain return values, and it resolves the main ambiguity (this records rather than charges). It is slightly thin on the mutation's irreversibility and duplicate-submission risk, which matter given destructiveHint=true and idempotentHint=false.

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 80%, so the schema already documents date, amount, customer_id, description, and the payment_method enum. The description adds no parameter syntax, format, or constraint detail beyond what the schema provides, so the 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+resource ('record a payment'), prefixes it as WRITE, and clarifies scope with 'bookkeeping only — it does not charge a card'. This quickly separates it from get_payment/list_payments, though it does not name any sibling 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?

The 'WRITE:' marker and the 'does not charge a card' note imply when this tool is appropriate (recording already-received funds rather than processing payment), but there is no explicit when-not guidance or named alternative such as get_payment or list_payments.

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