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

With no annotations, the description carries the full burden of behavioral disclosure. It transparently reveals the paid nature, the two-step payment flow, and the data returned (creators, launches, swap fees). However, it does not explicitly state whether the tool is read-only or has any side effects beyond payment. Given the context of a data-retrieval tool, this is a minor gap but the description is still highly transparent.

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 compact and front-loaded with the core purpose before diving into payment mechanics. It uses three sentences to convey purpose, cost, and usage steps without redundancy. The structure is efficient, though the payment details are dense and could potentially be broken out, but it remains appropriately sized for the complexity.

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?

Given no output schema and one parameter, the description covers the essential aspects: what data is returned (creators, launches, fees), the payment flow, and the cost. It does not detail the exact output format, but the nature of the data is described. For a paid tool with a two-step process, the description is sufficiently complete for an agent to call it correctly, though a note on expected response structure would enhance it.

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 single parameter `payment` is well-documented in the schema ('a signed x402 payment (the base64 payload you would put in PAYMENT-SIGNATURE)'). The description adds crucial context on when to pass it ('Call once without `payment` for the terms... call again with `payment`'), which goes beyond the schema's static definition. This helps the agent understand the temporal dependency, making it more than a simple parameter description.

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 states the tool's function: 'Who launched what on Arc and whether any of it ever traded: every repeat creator with their launches and the swap fees those launches earned.' This specific verb+resource distinguishes it from siblings like arc_fresh_launches (which likely focuses on fresh launches) and arc_agent_market (agents rather than creators). The purpose is unambiguous and not a tautology.

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?

The description provides explicit usage instructions: 'Call once without `payment` for the terms, sign them with your own wallet, call again with `payment`.' It also specifies the cost and payment methods ($0.004 per call over x402 on USDC/XNT). This is a clear when-to-use and how-to-use guide, and it differentiates the two-step payment process from typical one-shot calls.

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