postal_code

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

No annotations are provided, so the description must carry the full burden. It only states the lookup nature and data source. It does not disclose whether the lookup is read-only, what happens if the postal code is invalid, rate limits, authentication needs, or the structure of the return value. The description is too minimal for a tool with no annotation safety net.

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 a single sentence that is front-loaded with the action and resource. Every word adds value, and there is no unnecessary repetition or fluff.

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?

The tool has low complexity (one parameter, no nested objects) and no output schema. The description mentions the fields returned (locality, municipality, district, streets) but does not specify the output format, structure, or how to interpret the result. This is adequate but incomplete for an agent to reliably use the tool without further assumptions.

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 input schema has 100% coverage with a description for the parameter. The tool description does not add any new semantic information about the parameter beyond what the schema already provides (e.g., example format). Following the rubric, baseline 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 clearly states the action ('Look up'), the resource ('Portuguese postal code'), and the specific data returned ('locality, municipality, district and streets'). It also identifies the data source (GeoAPI.pt). This clearly distinguishes it from sibling tools like fuel_prices or weather_forecast.

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 provides no guidance on when to use this tool versus alternatives. It does not mention prerequisites (e.g., valid postal code format), when not to use it, or how it compares to related tools like reverse_geocode or municipality.

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