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

With no annotations provided, the description carries the full burden and does so well. It discloses that the tool has no keys and signs nothing, specifies the EIP-191 canonical-JSON signature requirement, states the success condition ('facilitator reports ok=true'), and reveals the side effect that a new grant supersedes the previous one.

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 description is dense but every sentence adds value: what it publishes, the goal, the success signal, the payload shape, and the signing semantics. It is front-loaded with the core action and then provides necessary detail without fluff.

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 tool with one opaque parameter, no annotations, and rich sibling context, the description is complete. It explains how to construct the signed grant, how signing works, what the facilitator checks, and what the outcome is; since an output schema exists, omitting return-value details is acceptable.

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 input schema is nearly empty—one object with additionalProperties true and 0% coverage—so the description must define the parameter, and it does. It specifies the signed_grant structure, required fields (type, agent, budgetUsdc, noConfirmUsdc, period, validBefore, nonce), the signature format, and the enforcement that the recovered signer is the owner.

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 ('Publish a signed spend-authority grant') and a clear resource/goal ('bind an agent wallet to a spend envelope') with budget, threshold, and expiry. It also differentiates from siblings by explaining that this tool carries no keys and signs nothing, and that new grants supersede previous ones.

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?

The description clearly conveys when to use the tool: to publish a pre-signed spend-authority grant and make it live for the next verification. It also implies the prerequisite that the owner must sign locally, but it does not explicitly contrast this with sibling tools like revoke_spend_authority or get_spend_authority.

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