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

Beyond the annotations, the description discloses the payment-step output shape (payment.url, bank-transfer instructions, voucher, pay_link validity), the cart-freeze behavior in path B, account creation on payment success, and the stock_changed recovery flow. It also explains auth and the op_id dedupe window, which usefully qualifies the idempotentHint=false annotation without directly contradicting it.

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 description front-loads the core action and organizes the workflow into path A, path B, stock_changed recovery, auth, and op_id idempotency blocks with little filler. It is dense and repeats some parameter rules already present in the schema, which keeps it from being maximally concise.

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 complex multi-step order/payment mutation with no output schema, the description supplies the important return signals (payment.url, pay_link, stock_changed/ready) and the sequencing constraints needed to call it safely. Auth and retry semantics are also covered, so nothing critical 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 coverage is already 100%, so the baseline is 3. The description still adds workflow meaning to accept_terms, op_id, add, and the agreed total, linking them to explicit consent, dedupe, stock replacement, and confirmation. It does not add much independent meaning for payment_method or accept_stock_changes beyond the schema, so 4 rather than 5.

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 opens with a specific verb and resource: 'Place the order and start its payment.' It also distinguishes the two placement paths (confirmed email vs. pre-confirmation) and ties the tool to the order reference from start_order, so an agent can separate it from cart and payment-check 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?

It gives explicit when-to-use guidance: confirm total and terms first, send accept_terms only after explicit consent, and use the reference from start_order. It also names alternatives/related tools such as start_order and check_payment, and states the stock_changed retry condition after shopper agreement.

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