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

With no annotations, the description carries the burden well: it discloses per-call pricing (1 CRD charged even on rejected calls), the exception for 429 RATE_LIMITED, and that errors carry a request_id to quote to support. It does not state auth requirements or what happens when the user has no wallet on file, which is the remaining gap.

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?

Two sentences: purpose first, then cost/error behavior. Nothing is repeated and no sentence is wasted.

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 lookup tool with no output schema, the description conveys the essential return fields and the billing/error surface. It stops short of explaining how the five optional identifiers resolve (which one is effectively required to find a user) or what a null/unset wallet result looks like.

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%, so every parameter is already documented, including email being checked first and x402_payment only following a PaymentRequired failure. The description adds no parameter-level meaning beyond the schema, so the baseline 3 applies.

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?

"Read the EVM address on file for an end user" gives a specific verb (read) and resource (stored wallet address), plus the extra returned state (verified, verified_at). It is clearly a read counterpart to set_user_wallet, but it never names that sibling, so the differentiation is left implicit.

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?

Usage is inferable: call this to look up a user's stored wallet and its verification status. There is no explicit when-to-use/when-not guidance and no pointer to alternatives such as verify_wallet_signature or request_wallet_challenge for a wallet that is not yet verified.

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