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

Adds substantial behavior beyond the annotations: default paid_from is the bank account, the entry hits 'Expense claims to repay', sepa_file generates a bank-uploadable credit transfer to the iban, and a cost of $0.01 per call with no charge on failure. This is exactly the kind of non-obvious consequence (money movement plus billing) an agent needs.

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 verb and resource, then mode semantics, then the SEPA and cost clauses. Dense and somewhat run-on in the middle, but every clause carries information an agent needs.

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 9-parameter, non-idempotent money-moving tool with no output schema, the description covers the important gaps: default account, counterpart posting, SEPA output, and failure charging. Only minor parameters (reference, date, bic) are left unelaborated.

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 only 56%, and the description compensates well for the undocumented params: it explains person (as paid_by had it), claims-vs-all-claims semantics, currency selection across open claims, the paid_from default, and what sepa_file/iban actually produce. It leaves reference, date, and bic meaning to the schema, hence not a 5.

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 and resource with a plain-language gloss ('Pay back what someone paid for the business with their own money'), and ties claims back to books_record_expense with paid_by, distinguishing it from books_record_expense and books_list_claims.

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?

Explains the two operating modes (all their open claims in one currency, or the claims named) and where the claims come from. It does not explicitly name when not to use it or point to a sibling alternative, but context is clear.

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