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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the trailing 'Read-only' adds nothing. The description does add genuine behavioral context by disclosing the scope of the data (service area boundaries, fee, cutoff), but says nothing about freshness of fee/cutoff data or failure behavior for unserved ZIPs.

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?

A single dense sentence that front-loads the primary content (delivery area) before the secondary details (fee, cutoff, per-ZIP check). 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?

With no output schema, the description carries the burden of describing return values, and it does so adequately by enumerating the four pieces of information returned. It falls just short on edge cases, such as what is returned for an unserved ZIP or whether fees are per-order or per-address.

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 coverage is 100% and there is only one optional parameter, so the schema already documents it fully. The description adds only that the ZIP determines whether the area is served, which is a marginal restatement rather than new semantic detail. Baseline 3 applies.

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?

Names a specific resource (Jockey Delivery service area, fee, cutoff) and enumerates exactly what the tool returns, including the conditional ZIP lookup. This clearly distinguishes it from checkout and catalog siblings.

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 implied by the content (an informational lookup for delivery eligibility/pricing), and the optional zip parameter signals a per-ZIP check. However, there is no explicit when-to-use guidance, no statement of when not to call it, and no named alternative.

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