buy

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

With no annotations, the description carries the full load and does well: it discloses the paying wallet (PARANOID_PAYER), exact pricing (0.002 USDC per question + 0.30 setup), the 250-question floor, and the side effect that an existing membership is retained beside the new one. It omits failure/irreversibility behavior for a real-money payment and never says what a successful call returns.

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?

One dense sentence covering purpose, cost, minimum and side effect, with the action front-loaded. Phrasing is slightly run-on and the wallet/file details interleave, but nothing is padding.

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 one-parameter payment tool with no annotations and no output schema, the description covers cost, chain, wallet, minimum and persistence of prior membership - enough to invoke correctly. Remaining gaps are payment failure handling and return payload, which is what keeps it from a 5.

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% and the single parameter is documented, so the baseline is 3; the description earns an extra point by tying 'questions' to a per-question price and a hard minimum, letting the agent compute total cost (e.g. 250 questions = 0.80 USDC) before calling.

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 and resource (buy a membership) plus the payment rail (x402 USDC on Solana) and the wallet used, which is unambiguous against siblings ask/models/balance. An agent knows exactly what the tool does without opening the 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?

Implies the usage context clearly - you buy a membership when you need a question quota - and the note that an existing membership is preserved gives the agent a reason it may still be safe to call. It never names an alternative or an explicit when-not condition, which keeps it below a 5.

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