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

With no annotations, the description carries the full burden and does well: it discloses the side effect (address stored and marked verified), the consumption of the nonce even on rejection, the per-call credit cost including on rejection, the 429 exemption, and that errors carry a request_id for support. The one gap is return shape on success (no output schema exists), which is only partially covered by 'the address is stored and marked verified'.

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?

Four dense sentences, front-loaded with the action and outcome, then consequences and cost. No filler, and each clause (single-use, cost, 429 exemption, request_id) carries information an agent needs before calling.

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 7-parameter, no-annotation, no-output-schema mutation tool, the description covers preconditions, cost, nonce lifecycle, and error handling well. It stops short of describing what a successful response contains beyond the verification effect, which is the only material omission.

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 the schema already explains nonce provenance, the address guard, chain_id provenance, and when x402_payment applies; the description adds little field-level meaning beyond reinforcing that the signature is a personal_sign output. Baseline 3 is appropriate since the schema does the parameter work.

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 action ('submit the personal_sign signature over the challenge message') plus the outcome ('the address is stored and marked verified'), and the 'Step 2' framing ties it to the challenge-issuing sibling rather than any credit/subscription tool. An agent can distinguish this from request_wallet_challenge and the rest of the sibling list without opening a schema.

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?

Explicit about the precondition (a challenge nonce, obtained in step 1) and about the retry path: a challenge is single-use, a rejected signature consumes it too, so a retry requires a fresh challenge. It also gives the cost trade-off that determines whether a retry is worth making.

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