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

Annotations only declare readOnlyHint=true, and the description meaningfully adds the supported resource types, the unsupported ones (quotations, drafts), the exact fields returned, and the underlying endpoint. It does not cover auth/permission needs or behavior for invalid or unbalanced vouchers, 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?

A single dense sentence covering scope, exclusions, and return fields, followed by the endpoint. The field enumeration makes it a little list-heavy, but no sentence is wasted and the scope constraint is front-loaded.

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 carries the return-value burden and does so by naming the fields and enumeration values (balanced/openRevenue/openExpense). Combined with the readOnly annotation and 100%-covered schema, an agent has nearly everything needed; only error/edge-case behavior is 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% and there is a single parameter, so the schema already documents voucher_id including its origin (lexware_list_vouchers) and UUID pattern. The description adds no further parameter meaning, making the baseline 3 correct.

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?

Specific verb+resource (get a voucher's payments) with the exact return payload enumerated (open amount, status, paid date, payment items). It scopes the eligible voucher types (invoice, credit note, down payment invoice, bookkeeping voucher) and explicitly excludes quotations and drafts, which cleanly separates it from siblings like lexware_get_invoice or lexware_get_quotation.

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?

Gives an explicit when-not ('Not available for quotations or drafts') and implicitly defines the use case through the enumerated voucher types and returned payment fields. It stops short of routing the agent to a specific alternative tool (e.g., lexware_get_invoice) when the voucher is a quotation or draft, so it is clear context without full alternative guidance.

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