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

Annotations only declare destructiveHint=true; the description clarifies that this is destructive only under replace_existing, which REPLACES all earlier payment entries, while the default is additive. It also flags the operation as 'Not fiscal' and describes the balance mutation. Return shape is not covered, keeping it short of a 5.

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 tightly packed sentences with zero filler; the core action and target lead, the add-vs-replace contract follows immediately, and the non-fiscal caveat closes. Every sentence carries distinct information.

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 compensates by stating the effect on paid amount and outstanding balance and the replace contract, which is what an agent needs. Only the response/confirmation format and any permission requirements are 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?

Schema description coverage is 100%, so all four parameters are already documented in the schema, including currency rounding behavior and replace_existing semantics. The description restates the add/replace behavior but adds no format or syntax detail beyond the structured fields, 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 (Records) and resource (1-5 payments) on a precisely scoped target (your own issued invoices or pro forma invoices), and names the downstream effect (updates paid amount and outstanding balance). No sibling handles payments, so it is cleanly distinguishable from get_invoice / reverse_invoice / create_invoice.

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 scope constraint ('one of your own issued invoices or pro forma invoices') tells the agent when this applies, and the add-vs-replace boundary is spelled out. It lacks an explicit 'when not to use / use X instead' statement, but no sibling overlaps the payments domain, so less routing guidance is needed than a crowded namespace.

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