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

With no annotations, the description carries full behavioral burden. It does disclose the useful trust model — payment is learned from Stripe's verified event, never from the browser — which tells the agent not to treat browser return as confirmation. But it omits URL expiry/reuse, whether the call is idempotent, and what the agent should do next (e.g., poll listing_status).

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?

Two dense sentences with zero filler; the return value is front-loaded and the trust-model caveat follows immediately. Every clause 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?

No output schema or annotations exist, so the description must be self-sufficient. It covers the return shape and confirmation semantics well, but leaves the id parameter and post-payment agent workflow unexplained for a payment-flow 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 only 50%: session is documented as coming from agent_session_verify, but id is a bare string with no description. The description never says what id refers to (presumably a listing identifier) — "at the site's price" only vaguely implies it, so it fails to compensate for the coverage gap.

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?

Concrete verb and resource: returns a Stripe Checkout URL for a listing payment, and the title disambiguates it as a human-completed hosted checkout. However, it never distinguishes itself from the similarly named sibling listing_pay_stripe, which an agent could easily confuse with this tool.

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?

"A human completes it in a browser" implies the condition under which this tool applies (human-in-the-loop card payment) versus programmatic payment siblings. But no alternative is named and there is no explicit when-not-to-use guidance, so the agent must infer the routing.

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