Reports: get sums report postingaccount ledger

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

Annotations already declare readOnlyHint and idempotentHint, so the description's main added value is explaining that the ledger is generated on the fly, no report must be created beforehand, and large ledgers may take a while. This is useful behavioral context beyond the structured annotations.

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 reasonably compact and front-loads the read-only nature and the core purpose. There is some redundancy, such as repeating the tool name as a bold heading and restating read-only behavior already present in annotations, but it remains clear and scannable.

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?

Given there is no output schema, the description provides the essential invocation context: what the ledger contains, where valid postingaccount numbers come from, the on-the-fly generation, and a performance caveat. It does not describe the exact output structure, but that is not strictly necessary for correct selection and 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?

The input schema already documents all five parameters with useful details including date formats and api_key behavior, so the baseline is 3. The description adds meaningful guidance by telling the agent that valid postingaccount_number values can be obtained from reports/get/sums, which helps avoid invalid calls.

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 clearly states the verb ('Returns') and the resource ('postingaccount ledger' / 'Kontenblatt') for one postingaccount. It also distinguishes this from the aggregated sums report by explicitly mentioning the report itself is created on the fly.

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 explains that postingaccount numbers come from reports/get/sums, and contrasts this ledger with the report itself, implying when this tool is appropriate without needing to create a report first. It does not explicitly enumerate alternative tools or exclusions, but the context is clear enough.

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