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

No annotations exist, so the description carries the full burden and it does disclose the key behavioral facts: a checkout_url is returned for the buyer to complete payment, the sale is attributed to agent_name for commission, and Coinbase delivery depends on customer_email. It omits auth prerequisites (the schema mentions a JWT fallback), session expiry, idempotency, and what happens if a session is never completed.

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?

Five short sentences, each carrying distinct information: purpose, payment options, return value, commission attribution, discovery pointer, and Coinbase delivery caveat. Front-loaded with the core action and no redundant restatement of the tool name.

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 and no annotations, the description covers the essentials: what is returned (checkout_url), how the caller is identified (agent_name/JWT), and the Coinbase email requirement. Missing auth/authentication expectations and failure modes keep it from being fully complete for a payment-creating tool.

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 meaning beyond the schema by explaining the consequence of payment_method choices (crypto currencies accepted, stripe default) and the delivery impact of customer_email for Coinbase, which the schema only states as a requirement rather than a workflow effect.

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 and resource ('Create a checkout session for a Bazaar catalog item'), names the supported payment processors, and implicitly separates itself from the read-only siblings (search_bazaar, list_bazaar_product, get_product_details). An agent can identify what this tool does without opening the 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?

Gives an explicit prerequisite flow ('Use search_bazaar to find catalog_item_id values') and a conditional instruction for Coinbase ('include customer_email to trigger automatic download delivery'). It does not state when not to use this tool versus e.g. list_bazaar_product or transfer_credits, but the purchase context is unambiguous.

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