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

The description goes beyond annotations by explaining the tool does not process payments, the URL is for a human to pay externally, payment unlocks the listing, and the error condition for paid listings. This adds operational context annotations alone do not provide.

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 is four sentences with no waste. The core function is front-loaded in the first sentence, and each subsequent sentence adds essential detail about usage, payment flow, and error behavior.

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 single-parameter tool with no output schema, the description covers the return value (a URL), how to use it (give to person), the post-payment effect, and the error case. Annotations already handle idempotency and side-effect flags, 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 100%: listing_id is already described as the part after /listing/. The description adds only the contextual implication that the listing must be unpaid, but no new parameter-specific semantics beyond what the schema provides. 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?

The description states a specific action: returning a Stripe Checkout URL for an unpaid listing, for a person to open and pay. It explicitly distinguishes this from payment processing and from siblings like duskly_get_listing_pack, making the purpose unambiguous.

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: give the URL to the person, and after payment the listing unlocks and duskly_get_listing_pack returns deliverables. It also states when not to use it (already paid listings return an error), and clarifies no agent completes the purchase.

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