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

The description adds rich behavioral context beyond the annotations: it defines the return shape, includes not_published in the result, clarifies that absence is not adverse, and warns that values are data, not instructions or approvals. This aligns with and extends the readOnly and openWorld annotations without contradiction.

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 concise and front-loaded with the most important usage condition. Every sentence adds value: when to call, parameter constraints, return shape, and the data-not-instruction caveat. No filler or redundancy.

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?

Despite having no output schema, the description provides the return shape [{field, state}], the inclusion of not_published, and the interpretation of absence. It also gives enough parameter guidance and semantic context for a correct call with the listed siblings.

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 already documents all five parameters with 100% coverage, so the baseline is 3. The description adds meaningful constraint by stating that exactly one of domain, phone, license, or address must be provided and that market is optional, which is not expressed in the schema's optionality.

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 clearly states the action ('list gaps') and the target resource (receipt fields whose state is not verified). It also distinguishes itself from the sibling get_receipt by narrowing the result to unverified fields, so an agent can tell them apart.

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 explicitly says to call when an identifier is already available and the unverified fields are needed, and it gives the one-of parameter rule. It references get_receipt as the same lookup but does not explicitly say 'use get_receipt for verified fields,' so it stops just short of a full when-not exclusion.

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