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

Annotations only carry generic readOnly/openWorld/idempotent/destructive hints, and the description supplies the behavior that actually matters here: a per-call monetary charge, that payment is owed even on a negative result, and that no bridge state is mutated. The x402 client requirement is a hard practical constraint an agent would otherwise miss.

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 short sentences, cost front-loaded, then scope, then return values, then the two constraints that prevent misuse. No filler and nothing repeated from the schema.

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?

With no output schema, the description carries the burden by naming the returned fields (roles, counterpart addresses, wrapped supply, contract checks, block evidence), and it also resolves the paid-negative-result ambiguity and the client prerequisite. Nothing an agent needs to call this correctly is 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 100% and both enums are documented in-schema, so the baseline is 3. The description restates that the token may be original or wrapped, echoing the token param, but adds no format, default, or interaction detail beyond the schema.

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 verb ("Inspect") and resource ("an original or wrapped token on Arc or Base") plus the underlying machinery (Circle CTS, CrossChainTokenService, CCTP) and enumerates what is returned. An agent knows exactly what the call does without opening the schema, and there are no siblings to disambiguate against.

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?

Gives clear operating context: 0.007 USDC cost per lookup, "No bridge execution," "A missing bridge is a valid paid result," and a client prerequisite ("Requires an x402-capable client; never request private keys"). It stops short of stating explicit when-to-use/when-not conditions, but with no sibling tools the remaining gap is small.

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