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

Beyond the annotations (which only say it is not read-only and is open-world), the description discloses that the listing goes live immediately with no review step, a per-domain uniqueness constraint, and a specific rejected input value. What remains unstated is what happens on failure or what a successful response contains.

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?

Four short sentences, with the side effect (goes live immediately) placed right after the action and the constraints following. No filler and nothing redundant with the schema.

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 three-parameter mutation with no output schema, the description covers the key risks: immediacy, the domain uniqueness rule, and one rejected value. It could go further on what the email is used for and what a successful submission returns, but the essential calling information is present.

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 33%: only tier carries a description, and url/email are bare strings. The description partially compensates by explaining that the placeholder URL is refused, but it says nothing about the email parameter's role or the URL format accepted, leaving a real gap for a required field.

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?

"List a product" names a concrete action and the resource being created, and "It goes live immediately" clarifies the outcome. It does not, however, distinguish this from the sibling x402_submit_listing or upgrade_listing, so an agent must infer which submission path applies.

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 description gives real preconditions: one listing per root domain, and the documentation placeholder URL is refused. It never states when to choose this over x402_submit_listing or upgrade_listing, so the selection guidance is only implied.

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