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

Annotations already declare readOnly, idempotent, non-destructive. The description adds cost ($0.008 per call), the HTTP method (GET), and the data source (U.S. Census 2022 NAICS). These are useful behavioral details beyond the annotations. No contradictions.

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?

One compact sentence conveys the purpose, two usage modes, expected output, source, and cost. It is front-loaded with the core function and contains no fluff. Every element earns its place.

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 lookup tool with two parameters, the description covers the main behavior (code vs. keyword) and the return type (title, hierarchy, children). It lacks a caveat about required parameters (none are marked required) but implies you need one of the two. The source and cost details add context. This is largely complete for a tool of this complexity.

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% — both parameters are described with examples. The description adds no extra semantic meaning beyond what the schema provides (e.g., it does not explain mutual exclusivity or what happens if both are provided). Baseline 3 is appropriate given the schema's completeness.

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 states the specific resource (NAICS lookup) and the two operations (code → title/hierarchy/children, and keyword search). It is clearly distinct from all sibling tools, which cover different domains (airports, weather, DNS, etc.), so an agent can easily differentiate it.

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 indicates the two modes ('code' or 'keyword search') and what each returns. It implicitly tells the agent when to use it (when NAICS info is needed). It does not explicitly compare to alternatives, but none of the siblings are relevant, so the guidance is sufficient.

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