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

Annotations already declare the operation read-only, open-world, idempotent, and non-destructive, so the description only needs to add context beyond that. It adds a demo-mode/sample-cities caveat, but it does not clarify what demo mode means or what happens for non-sample cities.

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 only two sentences, with the core action and resource front-loaded. There is no filler, though the second sentence is vague and could benefit from additional clarity.

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 should clarify what a ZIP profile contains, but it leaves the exact return shape unspecified. The demo-mode limitation is also not fully explained, yet the tool is simple enough that the basic contract—provide city and state, receive ZIP profiles—is understandable.

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?

Both parameters are fully documented in the schema with examples, so the description does not need to compensate for missing schema coverage. It only restates that the tool takes a city and state, and the demo-mode sentence only vaguely constrains the name parameter.

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 names a specific action, 'Return', and a specific resource, 'ZIP profiles', scoped by city and state. This largely distinguishes it from related tools like geo_zip_lookup and geo_county_lookup, though the demo-mode sentence introduces slight ambiguity about city coverage.

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?

There is no guidance about when to use this tool versus alternatives such as geo_zip_lookup, geo_county_lookup, or geo_enrich. The demo-mode sentence hints at a limitation, but it does not explain when the tool is appropriate or when it should be avoided.

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