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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely new context: results are 'computed on the server from live Fortnox data' and aggregate 'over all pages', telling the agent there is no client-side pagination or syncing to worry about.

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 content is front-loaded and short: scope first, example question second, data provenance last. Minor waste in that the opening clause restates the title verbatim, and the Swedish/English mixing adds slight friction, but nothing is padded.

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 annotations and an output schema present, the description only needs to establish scope and data provenance, which it does. The remaining gap is sibling differentiation against list_due_dates and get_receivables_aging, which an agent might reasonably hesitate between in a tool list this dense.

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 single optional 'date' parameter is fully documented in the schema, including the YYYY-MM-DD and month-end shortcuts. The description adds nothing about the parameter, so the schema does all the work — the baseline 3 is appropriate.

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 first clause names a specific verb+resource pair: an aging analysis of supplier payables, broken down 'per intervall och per leverantör'. An agent can distinguish it from get_receivables_aging (customer side) by the word 'leverantörsskulder', but the description never explicitly contrasts it with list_due_dates or the receivables counterpart.

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 'Example question: "Vilka leverantörsfakturor har vi låtit förfalla, och hur länge?"' implies the use case well, but usage is conveyed only by example. There is no explicit when-to-use statement and no guidance on when to prefer list_due_dates or list_supplier_invoices instead.

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