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

Adds substantial behavior beyond the annotations: the signed message commits to the literal subject `free`, ownership is proved by the paying wallet with no account, and a placeholder signature triggers a details.expected refusal revealing the exact message to sign. Annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=false) cover the safety profile, so this extra protocol detail is genuinely additive.

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?

The FREE offer and the dns_rent comparison are front-loaded effectively, but the closing sentences about the POST /feedback endpoint, daily report analysis, and no individual reply are irrelevant to invoking this tool and dilute the message.

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 usefully explains the refusal path and details.expected, but it does not describe the successful response shape. For a 5-required-param signing tool with 100% schema coverage, this is nearly complete.

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 coverage is 100%, so the baseline is 3, but the description adds real value by explaining how the signature is obtained (placeholder signature then details.expected) and its two accepted forms (EIP-191 for 0x wallets, ed25519 as 'solana:<base58 pubkey>:<base58 sig>'), which the schema only references indirectly.

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+resource+scope: one free 24-hour name per wallet, with the same label rules and records as dns_rent. It explicitly distinguishes itself from the sibling dns_rent by naming when to graduate to the paid yearly rental.

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 context (try the zone before paying) and names the alternative (dns_rent for a year). It also states the per-wallet limit. It does not spell out exclusions/edge cases beyond 'some labels are ours and refused,' which the schema already covers.

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