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

No annotations, so the description carries the full burden — and it does real work: it discloses the three return fields (x402_url, pay_url, claim_url) and, critically, "Does not move money itself," which tells the agent this is a checkout-creation step, not a charge. Gaps remain on auth requirements, idempotency, and link expiry, which matter for a paid checkout tool.

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?

Three short sentences, no waste, with the escape-hatch condition front-loaded before the return values and the non-mutation caveat. Every sentence earns its place.

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 an 18-parameter generic checkout tool with no output schema and no annotations, the description covers the essentials: selection rule, return shape, and the money-movement caveat, while per-SKU parameter scoping is delegated to a fully documented schema. It stops short of covering failure modes or payment flow details an agent might need.

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 100% and each of the 18 parameters already documents which SKU it belongs to (e.g., address for sanctions-wallet-screen, license_line for tx-insurance-ce-check). The description adds no parameter-level meaning beyond the schema, so the baseline 3 applies.

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 concrete verb+resource ("Creates a Coinbase checkout for any SKU") and frames the tool's role as the generic fallback, which separates it from the fifteen-plus job-named siblings like vet_load, check_carrier_authority, or get_fx_official. An agent can tell instantly whether this is the right tool or whether a specific one exists.

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?

"use this when no job-named tool exists" is an explicit routing rule, including an implicit when-not-to-use (a named SKU tool exists). It does not name list_shelves as the discovery path or the specific sibling examples, but the selection logic itself is unambiguous.

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