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

Goes well beyond the annotations by disclosing side effects and mechanics: opens Mahnen on the invoice, reuses saved reminder text, adds a Mahngebühr line when a fee is passed, sends by email, customer receives it immediately, and it appears under Mahnungen. It also flags per-call confirmation and that the action reaches other people, plus the API-key requirement — rich context for a mutating, open-world tool.

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?

Front-loaded with the core action and dense with useful detail; every sentence carries information. Minor overlap between 'sends the reminder by email' and 'the customer receives it at once', but nothing is wasted.

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?

No output schema exists, but the description fully covers prerequisites (API key, invoice origin), side effects, confirmation behavior, and recipient visibility — everything an agent needs to invoke a mutating, people-facing tool correctly.

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 100%, so baseline is 3, but the description adds meaning beyond the schema by explaining the effect of fee_amount (adds a Mahngebühr line item) and that an omitted intro_text uses the user's saved text. Marginal but real added value over the field descriptions.

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 (send) and resource (Mahnung/Zahlungserinnerung) for an overdue invoice, and its scope is clearly distinguishable from sibling tools like send_document or record_payment. The agent knows exactly what action is being taken.

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?

Provides a clear precondition (overdue invoice) and an explicit exclusion: works only for invoices created in Lexware Office, not imported ones. It doesn't name an alternative sibling (e.g. send_document vs this), so it stops just short of 5.

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