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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: it references live delivery-quote / DHRC and 'fails closed when that container cannot serve the ZIP,' which is meaningful failure-mode transparency. It could say more about latency or quota, but this is solid.

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 tight sentences, front-loaded with the primary use case, followed by the underlying data source and failure behavior. No filler; every sentence 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 two-parameter read-only validation tool with full schema coverage and annotations, the description is nearly complete, adding failure-mode and data-source context. The main missing element is guidance on when to choose this over sibling offer tools, which would strengthen routing.

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?

Schema description coverage is 100%, so the schema already documents both parameters ('Sale container SKU,' '5-digit US ZIP code'). The description adds no parameter-specific syntax or constraints beyond what the schema provides, making the baseline 3 appropriate.

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 clear validation purpose: 'validating whether a specific Sale SKU can be delivered to a ZIP and what delivery/delivered totals apply.' This identifies the verb (validate/check) and resources (Sale SKU, ZIP, delivery totals). It does not explicitly differentiate from siblings like get_sale_offers or get_rental_offers, which is the only gap.

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 phrase 'Use this when validating whether...' implies usage context but does not specify when to prefer this tool over siblings such as get_sale_offers or get_rental_offers, nor does it state exclusions. It provides only implied guidance.

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