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

With no annotations, the description carries the burden, and it does well: 'How to accept' signals an instructional/read-only tool rather than a payment-execution action, and 'Free' plus 'verified on chain while doing it ourselves' gives useful context. It stops short of explicitly saying it returns a guide and has no side effects, but nothing in the text implies mutation or external side effects.

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 single sentence is front-loaded with the main purpose and then lists concrete content areas without fluff. It is slightly dense as one long sentence, but every component carries information and 'Free' is a meaningful one-word signal.

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 no-argument, no-output-schema informational how-to, the description provides enough detail to select and invoke it correctly: it names the network, payment asset context, and the main topics. It does not describe the exact return format or step-by-step structure, but that is not required for an agent to decide to call this guide.

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?

The tool has zero parameters and 100% schema coverage, so there are no parameter ambiguities to resolve. The description adds useful topic-level context, which is the baseline expectation for a no-parameter tool.

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 — 'How to accept x402 payments on Arc' — and enumerates exactly what the guide covers: signing domains, settlement logs, gas cost, and settlement options. The 'how_to' name plus content clearly separates it from the sibling x402 inspect/test/stats tools.

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 gives clear context for when to call it: when the agent/user needs instructions on accepting x402 on Arc, and it notes the information is on-chain verified and free. It does not explicitly name alternatives or say when not to use it, but its informational framing is enough to avoid confusion with sibling payment-testing/inspection tools.

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