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

Beyond the annotations (readOnlyHint, openWorldHint, destructiveHint=false), it discloses the result cap (100, no paging), relevance ranking, that limits follow the caller's key plan, that the catalogue is static and unaffected by contract refreshes, and that returned fields are untrusted scraped data to be treated as data. That last point is a meaningful safety disclosure the annotations do not carry.

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?

Dense and front-loaded: purpose, input forms, output shape, downstream wiring, then caveats. A few clauses restate structured data ('limit caps at 100', 'Read-only'), but they are minor and the overall length is justified by the tool's role in a multi-step workflow.

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 carries the burden of describing returns, and it covers count, ranking, and no-paging, plus the untrusted-data caveat. It stops short of naming the returned fields (code, title, description), which would fully close the gap for a lookup tool.

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%, so the baseline is 3; the description adds example keyword and code-prefix values and reiterates the 100 cap, which helps an agent pick a query. It does not clarify the relationship between the 'q' alias and 'keyword', which is the one ambiguity left in the schema.

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?

States a specific verb and resource ('Look up NAICS codes') and immediately defines the resource ('NAICS codes classify a business's industry, used to match contracts'). It is clearly distinct from siblings like search_contracts or get_states, which handle contracts and geography rather than the industry catalogue.

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?

Explicitly tells the agent when to use it ('find the right code first, then pass six-digit codes in search_contracts.naics_codes, or a 2-5 digit family prefix in search_contracts.naics_prefix'), naming the sibling parameters that consume the output. It also gives concrete input shapes ('janitorial', 'IT services', '5415'), removing guesswork about query format.

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