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

The description adds substantial context beyond the annotations: server-issued nonce, exact USDC price, two-phase settlement, opt-in with no recurring billing, retry safety, and a security warning about private keys. It does not contradict the destructiveHint annotation, though it does not elaborate on what destructive side effects may occur.

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?

Five concise sentences front-load the core two-phase flow and then add retry, safety, and billing details. Every sentence contributes useful information with no repetition or filler.

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?

The description covers the overall protocol, expected return values (price, duration, nonce), retry behavior, and the free baseline. However, with no output schema and no explanation of agent_key, plus an unaddressed destructiveHint, an agent is left with some uncertainty about authentication and full side effects.

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 0%, so the description must compensate. It explains order_id as the identifier reused across quote and settlement calls, and payment as the authorized wallet payment. However, it never mentions the required agent_key parameter and does not precisely map each parameter to the first or second call, leaving partial ambiguity.

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 clearly identifies the tool as a two-phase action: first quote, then settle/purchase optional higher write capacity. It uses specific verbs and a concrete resource, making it distinguishable from siblings like get_paid_services or fund_task.

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 provides clear process guidance: make a first call to receive a price and nonce, then make a second call with the same order_id and an authorized wallet payment to settle. It also instructs when to retry and warns against providing private keys, but it does not explicitly name alternatives or state when not to use this tool.

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