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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: the return is a signable message requiring personal_sign, the linked address is returned "if any," and fee crediting depends on the linked wallet. Return format details are left to the output schema.

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?

Three tight sentences with the usage trigger front-loaded, followed by return contents and the crediting caveat. Every sentence carries distinct, useful information with no padding.

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 zero-parameter read tool with an output schema, the description covers when to call it, what it yields, and why it matters (fee crediting). Since the output schema documents the return structure, nothing essential 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?

The tool takes zero parameters and the schema is fully documented, so there are no parameter semantics to explain. The description correctly implies a no-argument call, making baseline 4 appropriate.

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: it returns the message to sign (EIP-191 personal_sign) and the currently linked address. It situates the tool in the payment flow, which helps separate it from sibling mutators like link_wallet and verify_handshake_payment, though it never names those alternatives directly.

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?

"Use this before paying a Handshake fee in USDC for the first time" gives a clear triggering condition. The note that fee payments are only credited from the linked wallet implies the follow-up action when no address is linked, but the alternative tool (link_wallet) is not explicitly named.

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