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

The description adds meaningful behavioral rules beyond the annotations: the amount is in euros, a negative amount means a reversal (Rückbuchung), and omitting paid_on defaults to today. It does not describe permissions or full side effects, but the annotations already cover read-only, idempotency, and destructiveness hints.

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?

The description is two tight sentences with no wasted words. The key business rules are front-loaded and directly actionable.

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 non-idempotent mutation with four parameters and no output schema, the description covers the most important amount and date rules but omits note semantics, permission requirements, and any indication of what happens on success or failure.

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 only 25% schema description coverage, the description must compensate. It usefully explains amount sign semantics and the paid_on default, but it leaves the note parameter undocumented and does not clarify what id refers to beyond the schema's ambiguous 'Beleg-ID'.

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 states a specific verb and resource: recording an incoming payment for an invoice. It is clearly distinguishable from most sibling tools, but it does not explicitly differentiate itself from close alternatives such as create_credit_note, which could also involve negative amounts.

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?

It implies the tool is for recording payments but gives no explicit guidance on when to use it versus alternatives like create_credit_note, cancel_invoice, or issue_dunning. There are no exclusions or prerequisite conditions stated.

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