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

Beyond the annotations, it discloses a meaningful two-phase flow and the authorization prerequisite that the signer must be the payTo or ERC-8004 owner — context the agent cannot derive from readOnlyHint=false / idempotentHint=true / destructiveHint=false. It also clarifies that the no-signature branch is non-mutating, which tempers the write-capable annotation. It says nothing about error behavior on signature mismatch or what the returned token is used for.

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 of roughly 45 words, so length is appropriate and the mode split is front-loaded. The structure is telegraphic pseudocode ('With claimant + expiresAt + signature ..., or method well-known: verifies and marks the listing claimed'), which forces re-reading and leaves terms like 'well-known token' unexplained.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile. What is missing for a five-parameter tool at 0% schema coverage is the final link in the flow — that the returned EIP-712 data is signed and resubmitted with claimant/expiresAt — plus parameter format expectations and failure handling.

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?

With schema description coverage at 0% for five parameters, the description must carry the load; it does give semantic roles for signature, claimant, expiresAt, and method (well-known vs. eip712), and implies serviceId selects the listing. But it omits the format constraints the schema enforces (0x 40-hex claimant, 130-hex signature, numeric-string expiresAt), the expiry window meaning, and never states serviceId is the sole required field.

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 names the resource (listing) and two distinct operations: returning EIP-712 typed data plus a token, and verifying a signature to mark the listing claimed. However, the phrasing is compressed and jargon-heavy ('well-known token', 'ERC-8004 owner'), and it never contrasts this tool with the sibling 'verify', which performs a superficially similar verification action.

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?

It does give conditional invocation guidance: omit the signature to get typed data, or supply claimant + expiresAt + signature / method='well-known' to commit. That is implied usage rather than explicit guidance, and nothing states when to use this instead of find_service, get_order, or verify, nor any when-not conditions.

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