apiosk_fetch_paid

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

Annotations already flag destructiveHint=true, readOnlyHint=false, and idempotentHint=false. The description adds meaningful behavioral detail beyond those flags: the gateway refuses if the live price exceeds confirmed_price_usdc, it enforces wallet per-tx/daily spend limits, and only Base + USDC are supported. This gives an agent a realistic model of the tool's constraints and failure conditions.

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 three dense sentences with no filler: purpose, routing/alternative, required precondition, and payment limits. Each clause earns its place, and the most operationally critical guidance is clearly marked with 'REQUIRED.'

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 paid external fetch tool with 8 parameters, an output schema, and rich annotations, the description covers the essential operational context: when to use it, what prerequisite must be satisfied, how pricing is enforced, and what networks/tokens are allowed. Remaining details like request body, query, method, and idempotency are fully documented in the input schema, so the description does not need to repeat them.

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 description coverage is 100%, so the baseline is 3. The description adds extra semantic value by explaining that confirmed_price_usdc must come from apiosk_inspect_x402 and that the gateway rejects prices above that amount, and that the url must be an external discovery result. This is crucial context beyond the plain schema property descriptions.

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 uses a specific verb-resource pair: 'Pay an EXTERNAL x402 endpoint ... and return its data.' It also explicitly contrasts with apiosk_execute, so an agent can distinguish the two tools solely from the description.

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?

Provides explicit when-to-use and when-not-to-use guidance: 'Use this only for external results from apiosk_discover (executable_via="apiosk_fetch_paid")' and 'for Apiosk catalog listings use apiosk_execute.' It also mandates the prerequisite apiosk_inspect_x402 call and confirms the price beforehand.

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