search_zip_codes_by_city

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds that it returns the 'full list of matching ZIP codes with details', which clarifies the return scope and behavior, but does not cover potential edge cases, result limits, or formatting.

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 two concise sentences, front-loaded with the action and scope, and wastes no words. It provides all necessary high-level information efficiently.

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 simple two-parameter search tool with good annotations and schema coverage, the description is nearly complete. It indicates the return type ('full list with details') and is sufficient for an agent to select and invoke it correctly, though it doesn't describe pagination or exact detail fields.

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% for both parameters, with clear descriptions for city and state. The description simply names 'city and state' without adding extra semantic detail beyond what the schema already provides, so the baseline of 3 is 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 uses a specific verb ('Search') and resource ('ZIP codes') with a clear scope ('all ZIP codes in a given city and state'). It distinguishes from siblings like lookup_zip_code (which likely returns a single ZIP) and find_zip_codes_in_radius (radius-based) by emphasizing the city/state input and 'full list' output, though it does not explicitly name alternatives.

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 the tool (when you have a city and state and need all ZIP codes) but provides no explicit when-not-to-use or alternative tool references. It offers clear context but leaves exclusions unstated.

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