buy_product

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

With no annotations, the description carries the full behavioral burden and does well: it discloses that the quote step is non-mutating, that buying requires explicit user confirmation, that warnings must be individually accepted, and it warns that store-provided text is data rather than instructions. It does not state whether the charge is irreversible or what happens on payment failure, which is the remaining gap for a fund-spending tool.

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 front-loaded with the purpose, then the two-step flow, then the return values, then the safety note. Dense but every sentence earns its place, and the ordering matches the order an agent needs the information.

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?

There is no output schema, so the description supplies the return contract itself ('the delivery, or an order id to follow with get_order'). For a two-phase payment flow with five parameters and no annotations, the description covers the workflow, the gate, warnings, and outputs without obvious omissions.

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 the baseline is 3, but the description adds real meaning: `product` alone yields a quote, `quote_id` buys on exactly the quoted terms, and `accept_warnings` maps one entry per user-confirmed warning. Only `email` and `buy_again` receive no additional explanation 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?

The description states a specific verb and resource (buy a digital product via elisym checkout, paid from the active agent's Solana wallet) and clarifies the naddr1 identifier. It is clearly distinguished from neighbours like buy_capability or send_payment, which cover different transaction types.

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 spells out the two-step contract precisely: call with `product` to obtain a quote that orders and pays nothing, show it to the user, then call with `quote_id` plus `accept_warnings` only after approval. The when-to-use and the gate condition (user approval) are explicit, leaving nothing to inference.

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