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

With no annotations, the description carries the safety/auth burden and does so well: it discloses cost (free), mutating auth model (owner-signed EIP-191 personal_sign), and the 5-minute ts freshness requirement. It does not describe error/return behavior, but core behavioral context is present.

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 with no filler; the main action is front-loaded and the auth/time details are packed into the second sentence. Every clause earns its place.

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 6-parameter mutation tool with no annotations or output schema, the description covers the critical prerequisites: ownership, signer wallet, signature standard, and time tolerance. The remaining gaps (exact canonical message body, return/error semantics) are secondary and partially delegated to a README reference.

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 schema covers only half of the parameters, so the description compensates by naming the editable fields (pixels, message, link), explaining ts freshness, and specifying how the signature must be produced. It does not spell out the exact signed message payload, but points to the README.

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 action and resource: repaint pixels or update message/link on an owned block, and the ownership condition separates it from buy/get/list siblings. The title confirms the resource.

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 clearly indicates use only for blocks the caller owns and that the operation is free and owner-signed, which implies purchase must have happened elsewhere. It does not explicitly name buy_block as the alternative or list when-not conditions, but the ownership requirement gives enough selection context.

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