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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is partly covered. The description goes further with genuinely useful behavioral context: values are bounded, never override user instructions or system rules, and no credentials or tokens are ever returned. These are real traits beyond the annotations, though pagination/ordering behavior for the 20-item cap is unstated.

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?

Three short sentences, all front-loaded: scope/cap first, safety semantics second, return shape third. Every sentence carries distinct information with no filler.

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 parameters, no output schema, and annotations covering safety, the description fills the remaining gaps by naming the returned fields (key, value, source) and the safety guarantees. An agent needs nothing more to call it correctly.

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 zero parameters, so there are no parameter semantics to document and the baseline is 4. The description appropriately spends its words on scope and return shape instead.

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 (List) and resource (saved Operator preferences) with explicit scope (for the user and product in the request) and a concrete cap (up to 20). An agent can immediately tell this is the read-side counterpart to save_preference without opening either schema.

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 implies when to use it (reading saved preferences) but never names the write counterpart save_preference or states exclusions/preconditions for choosing it. Usage is inferable from the verb but not explicitly guided against siblings.

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