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

With no annotations, the description carries the full burden and does so richly: it discloses the return shape (url, mode, unlock_token), the test-mode card to pay with, that the token reads answers only after payment, the 409 awaiting_answers guard, that it does NOT POST to the asker's callback_url, and that pricing is USD with adaptive pricing off. These are exactly the side effects and payment semantics an agent needs.

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 purpose is correctly front-loaded in the first sentence, but the tail becomes fragmented and partly off-topic ('Poll unlock $1. Asker posts $1–$5. Reader unlock $1. Answers are free.') — pricing for the asker/answers does not help invoke this tool. The run-on sentences dilute an otherwise information-dense description.

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 payment-flow tool with no annotations and no output schema, the description covers return values, error behavior, side effects, and payment mode thoroughly. The remaining gap is parameter documentation (especially payer_type), which is the one thing an agent still cannot resolve.

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 0% and neither parameter is explained. The description implies ask_id's role ('an ask you did not post') but never documents the payer_type enum (human/agent), leaving a required decision undocumented in both schema and description. It does not 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?

States a specific verb+resource ('Separate $1 reader checkout for an ask you did not post') and pins it to an endpoint, making clear it is the reader-side unlock rather than create_checkout or unlock_poll. An agent can distinguish it from all siblings without opening a 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 clear context for use ('for an ask you did not post'), a follow-up step ('then get_ask with that token'), and a precondition (409 while awaiting_answers is true, so you don't pay for an empty thread). It stops short of explicitly contrasting with create_checkout or unlock_poll, so it is strong context rather than full when/when-not routing.

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