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

Annotations only declare readOnlyHint=true, but the description adds genuinely useful behavior: pagination at 100 per page and hard rate limits (60 requests/minute, 1000 per 24 hours) with the clarification that each call counts as one request. It does not cover auth requirements or ordering, so it stops 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?

Front-loaded with purpose and returned fields, then pagination and rate limits; there is almost no filler. It is dense and slightly list-like, but each clause carries constraints 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?

With no output schema, the description carries the return-value burden and does so: it enumerates the returned fields (date, partner, account, currency, amount, optional rows) and documents pagination and rate limits. Nothing an agent needs to call this correctly is missing.

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%, so the baseline is 3, but the description adds real meaning beyond the schema by explaining that the returned rows show which invoices were paid (the schema only says 'Include the payment rows') and by restating the 100-per-page paging tied to the page parameter.

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 (list) and resource (payments), scopes it to bank and cash payments from clients/to vendors, and even cites the backing endpoint (purchasesales/payments:get). An agent can distinguish it from list_purchase_invoices or list_ledger_entries without opening a schema.

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 implies this is the read path for payment records and notes the payment-vs-modification date filtering, but never states when to prefer it over siblings like list_purchase_invoices, get_vendor_balance, or create_payment. Usage is inferable rather than explicit.

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