Vorauszahlungen (Soll/Ist)

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description usefully discloses the dimensions of the result (plan vs actual per month, plus open amount and balance), but says nothing about how monthly rows relate to a partial year, what happens when no advance payments exist, or the currency/granularity of the balance – the schema hints the sums span the whole tenancy, which the description does not reinforce.

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 dense sentence with zero filler that front-loads both the comparison (Soll vs Ist) and the output shape. It is a noun-phrase fragment rather than an action statement, 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?

For a read-only reporting tool with a 100%-covered two-parameter schema and an output schema, the essential purpose is conveyed and safety is covered by annotations. What is missing is routing information – when to reach for this versus the other status/list tools – which matters given the crowded reporting sibling set.

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%, and the schema itself explains that year restricts months while sums always cover the full tenancy period and that tenant_id refers to list_tenants. The description adds nothing beyond 'eines Mieters je Monat', so it sits at the baseline where the schema does the work.

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 names a specific resource – a tenant's Nebenkostenvorauszahlungen – and states the exact content per month (Soll/Ist, offener Betrag, Saldo), so an agent knows precisely what data comes back. It lacks an explicit verb and does not contrast itself with related reporting siblings like get_billing_year_status or get_statement, which keeps it from a 5.

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?

There is no when-to-use guidance at all: nothing says whether this is for checking arrears, reconciling a statement, or preparing a billing run. No alternative or exclusion is named, leaving the agent to infer selection from the sibling name list alone.

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