x402 service catalog

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the agent knows this is a safe, open-world read. The description adds that it exposes pay-to wallets and pay URLs, but says nothing about rate limits, auth needs, caching, or result shape. Modest added value over annotations.

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?

A single sentence with the resource front-loaded and the two network values explained after a colon. No filler, though it is short enough that it could have carried one more routing hint at no cost.

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?

There is no output schema, so the description must convey returns, and it does name the returned content (wallets and their pay URLs). Combined with readOnly/openWorld annotations, it is largely sufficient for a simple one-param lookup, with only 'when to use it' and the default value missing.

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 carry the parameter meaning, and it does: base = USDC on Base, scdo = native SCDO on Shard0. This gives the agent real semantics for both enum values beyond the bare names, though it omits that base is the default.

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 resource ('Catalog of SCDO x402 pay-to wallets and their pay URLs'), which is distinguishable from siblings like x402_quote and x402_relay_status. It does not explicitly name what it is not, but the wallet/pay-URL scope is clear enough for an agent to select it.

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 never states when to call this tool or what alternatives exist (e.g., vs x402_quote or pay_x402). Usage is only implied by the noun 'catalog'. No prerequisites or context for use are given.

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