Record a payment

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

Annotations already declare this is a non-readonly, non-destructive, closed-world mutation, so the safety profile is covered. The description adds the gross-amount convention and the same-customer/same-tax-rate eligibility rule, but says nothing about what happens to the invoices afterward (state change, partial payment handling) or reversibility.

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?

Two sentences, no filler, with the core action and the gross-amount convention front-loaded. Every clause carries information the agent needs.

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?

An output schema exists so return values need not be described, and annotations cover the mutation safety profile. The description supplies the operation, its scope limits, and the amount convention - enough for correct invocation.

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 75% and the description still adds meaning beyond it: the eligibility constraints on invoice_ids (sent, open, same customer and tax rate) are not captured in the schema, and "amount is gross" reinforces the gross-amount semantics. Date and payment_method defaults are left to the schema, which documents them.

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 ("Records a payment") and narrows scope precisely: payments against one or more sent, open invoices belonging to the same customer and tax rate. No sibling tool creates payments, so the operation is unambiguous in context.

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 description embeds clear preconditions for use - invoices must be sent and open, and must share the same customer and tax rate - which tells the agent when this call is valid. It does not name an alternative tool or state when-not to use it, but no competing payment-creation sibling exists.

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