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

Annotations only declare the write/destructive/non-idempotent profile; the description adds substantial value beyond them: it creates a real book entry that this server cannot edit or delete, corrects must be made in SmartAccounts, it never retries and the caller should inspect SmartAccounts on an unclear reply, and it discloses rate limits (60/min, 1000/24h).

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-loads the core action, then layers operational detail (sources, currency rule, return fields, immutability, rate limit). It is on the longer side but each sentence carries distinct information, so little is wasted.

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?

No output schema exists, yet the description still names the returned fields (paymentId, number, amount), and it covers the mutation caveats, retry behavior and rate limits, leaving nothing essential for a correct call 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 coverage is 100%, so the baseline is 3, but the description adds cross-field meaning: the source of account_name (bank/cash account lists) and invoice ids (invoice lists) and the constraint that currency must match the account's currency.

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 ('Record') and resource ('bank or cash payment against one or more invoices'), and disambiguates the two scenarios (client paying a sales invoice vs. payment to a vendor) so an agent can place it among the invoice-related siblings.

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?

Explicitly routes the agent to smartaccounts_list_bank_accounts / _list_cash_accounts for account_name and to the invoice lists for row ids, giving clear context for when this tool applies. It stops short of naming when NOT to use it or which siblings (e.g. create_ledger_entry) are the wrong choice, so no exclusions are given.

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