Create customer

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

Annotations only declare openWorldHint=true, so the description carries nearly the full burden. It doesn't say whether the call is idempotent, what happens on duplicate email, whether an error is returned for unsupported providers (payu, cashfree, etc.), or whether auth/credentials per gateway are required — all material for an external write.

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?

A single front-loaded sentence with no filler; the supported-gateway qualifier is placed immediately after the action. It is arguably too terse for the information load, but that is an omission issue rather than verbosity.

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 5 parameters, a nested metadata object, no output schema, and no documented return value (e.g., customer id needed for later payments/subscriptions), the description is too thin. An agent cannot tell what it gets back or how to use the result in follow-on calls.

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 only 20% (only 'provider' is documented), so the description must compensate and does not: name, email, phone, and the nested metadata map are entirely unannotated in both places. The one added value is clarifying which provider values actually support customer creation, which partially offsets the gap but leaves four parameters unexplained.

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?

Specific verb + resource ('Create a customer record') and it adds a genuinely distinguishing qualifier: only gateways that support customers (Razorpay, Stripe) are viable. This differentiates it from sibling write tools like payments_create_payment or payments_create_subscription, though it doesn't explicitly contrast with them.

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 parenthetical implies when the tool is usable (only on Razorpay/Stripe), which is useful, but there is no explicit when-to-use vs. alternatives guidance and no statement of what happens if an unsupported provider from the 8-value enum is passed. Usage is inferable rather than stated.

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