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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real value by disclosing the shape of the payload (program name, points currency name, tier structure with required points per tier), which is not in any structured field since there is no output schema. It stops short of covering auth requirements or behavior when loyalty is disabled.

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, front-loaded with the action and scope, followed by the return fields. Nothing is redundant with the name and nothing is wasted.

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 carries the burden of explaining returns and it does so adequately by listing the three field groups. A minor gap remains around edge cases (e.g., site without a loyalty program), but for a zero-param read tool this is close to sufficient.

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 tool takes no parameters, so there is nothing for the description to disambiguate; baseline 4 applies. No spurious parameter talk clutters the definition.

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 and resource ('Get the loyalty/rewards program details for this site') and names the backing product (Wix Loyalty). No sibling tool covers loyalty, so there is no ambiguity to resolve, and the description even enumerates the returned fields.

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?

Usage is only implied: an agent can infer it should call this when it needs loyalty program configuration. There is no explicit when-to-use/when-not framing, no mention of what to do if the program is not enabled, and no alternative named — but with zero parameters and one obvious purpose, little guidance is genuinely needed.

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