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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the demo-mode limitation and production-workflow context, but does not clarify what 'enriched' means or what output consumers should expect; there is no contradiction with the annotations.

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 sentences with the core action front-loaded and the demo-mode caveat placed second. Every sentence earns its place and there is no filler.

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 one-parameter read-only tool, the schema and annotations cover invocation and safety. Because there is no output schema, a more concrete description of the returned enriched profile, such as its fields or structure, would improve completeness; 'profile shape' is vague.

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 the zip parameter is already described as a U.S. ZIP code with an example. The description adds no additional parameter semantics beyond implying that only selected ZIPs work in demo mode, so the 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 names a specific verb and resource: it returns the enriched ZIP profile shape, with production enrichment workflows as the context. It is clear enough to communicate that this tool provides ZIP enrichment rather than validation or IP lookup, but it does not explicitly differentiate itself from sibling tools such as geo_zip_lookup or address_enrich.

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 'used by production enrichment workflows' gives implied context for when the tool is relevant, and 'Demo mode allows selected sample ZIPs' hints at a trial/development mode. However, there is no explicit when-to-use versus any sibling, and no exclusionary guidance for geo_zip_lookup, geo_zip_batch, or address_enrich.

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