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

Annotations already cover read-only/idempotent/non-destructive; the description adds a meaningful trust and cost statement — the server never holds or spends funds, and the call itself is free, unlike the route it describes. It doesn't mention rate limits or error modes, keeping it below 5.

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?

A single front-loaded sentence with the returned fields grouped in a parenthetical and the trust caveat following immediately. Dense but no filler; slightly long for one sentence.

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 exists, and the description does enumerate what comes back (price, accepts[] fields, pay URL, free sample, ladder), so an agent can act on the response. It omits the shape of accepts[] entries' nesting and any error behavior, which leaves a small gap.

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%, so both parameters are fully documented in the schema, including the omit-to-get-template behavior. The description only adds the fact that inputs are substituted into the pay URL, which is marginal beyond the schema.

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: returns x402 payment requirements for a paid Avasis route, and enumerates the payload (price, accepts[], pay URL, free sample, also_available ladder). This is clearly distinct from avasis_products (catalog) and avasis_free_sample (free data).

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?

Explains the intended flow — your own wallet pays the HTTP route using this payload — and the schema ties the product key back to avasis_products. No explicit when-not conditions or named alternatives are given beyond that, so it stops short of 5.

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