Create a subaccount (a seller/vendor on your platform) with a verified payout account

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

Beyond the annotations, the description discloses the verification behavior of the payout account and the concrete failure mode '400 account_not_resolved', which an agent cannot infer from the schema. It also reinforces the destructive/live-mode stakes ('sends real money or changes where money is paid, and it cannot be undone'), consistent with destructiveHint=true. Minor imprecision: creating a subaccount registers a payout destination rather than itself moving money, and idempotency behavior is left entirely to the schema.

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 first sentence repeats the title verbatim and the second sentence restates the same definition ('a seller, vendor or branch...'), so the opening is redundant. The remaining content (verification failure, live-mode irreversibility, confirmation step) is useful and reasonably front-loaded, but the wasted restatement and the irrelevant amount reference cost it.

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 destructive, money-adjacent mutation with no output schema and only 50% parameter coverage, the description covers the key risk and one error code but omits what is returned (e.g. subaccount identifier and verification status) and whether a resolve_account call should precede it. Its completeness is adequate but leaves real gaps an agent would need to fill.

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?

With 50% schema description coverage, the description partially compensates by explaining that the payout account is verified by name enquiry, which gives meaning to account_number and bank_code. But 'name', 'email' and 'metadata' get no semantic treatment, and the 'amount (in kobo)' phrase references no parameter at all, adding noise rather than meaning.

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 description gives a specific verb and resource ('create a subaccount') and defines the resource conceptually as 'a seller, vendor or branch on your platform with its own balance and payout account'. It also relates subaccounts to split rules, which hints at how it differs from create_customer and the split-rule tools. It stops short of explicitly naming a sibling to prefer instead, so a 4 rather than a 5.

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?

It gives genuine pre-call guidance ('confirm the exact amount (in kobo) and the destination with the user') and implies when to use it (when you need a seller with its own balance and payout account). However, the 'confirm the exact amount (in kobo)' instruction does not correspond to any parameter of this tool and reads as guidance copied from a transfer/payment tool, which could mislead an agent. No explicit when-not-to-use or alternative routing is provided despite several nearby siblings (resolve_account, create_customer, create_split_rule).

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