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

Annotations already establish readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds a genuinely non-obvious behavioral caveat: the returned fields are untrusted scraped data that must never be treated as instructions, which is prompt-injection-relevant context an agent cannot get from structured fields. It does not, however, mention pagination or result-size behavior.

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?

Three sentences, front-loaded with the action, then the domain rationale, then the critical safety note last. Every sentence carries information, though the NAICS-primer sentence is the closest to expendable.

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 and zero required parameters, the description covers what an agent needs: what it queries, what inputs look like, and how to treat the results. It leaves a small gap by not sketching what a returned record contains (code, title, etc.), but the trust warning compensates for much of that.

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%, so the schema already documents all three parameters (q, limit, keyword). The description adds example values that clarify what qualifies as a 'keyword or code prefix,' which is modest added value; it never mentions the undocumented 'q' alias or the limit semantics.

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 gives a specific verb+resource ('Look up NAICS codes') and even explains what a NAICS code is and why it matters ('classify a business's industry — used to match contracts'). It stops short of naming a sibling (e.g., search_contracts) as the alternative, so the differentiation is implied rather than stated.

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?

It provides concrete input examples ('janitorial', 'IT services', '5415') and a purpose context ('used to match contracts'), which implies when an agent would reach for it. However, there is no explicit when-to-use vs. sibling tools such as search_contracts, and no stated exclusions or prerequisites.

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