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

Adds real behavioral context beyond annotations: results come newest-first, and each site not already returned this period consumes one unit of the monthly allowance, which is the key cost consideration and explains why readOnlyHint is false (metered read). It doesn't mention the confirm flow or paging behavior in prose, but those are covered by schema parameter descriptions.

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, each doing distinct work: what it returns, when to use a sibling instead, and the quota implication. The primary purpose is front-loaded and no sentence is padding.

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 10-parameter, no-output-schema query tool, the description covers purpose, ordering, routing, and billing impact. Return shape is only implied ('sites... newest first'), which is a minor gap given no output schema exists.

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 all ten parameters are already documented in the schema, including near/radius pairing, date bounds, and confirm. The description itself adds no parameter-level detail, so the baseline 3 applies.

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+resource ('Sites detected using one specific technology') and adds an ordering guarantee ('newest first'), which no sibling name conveys. It is clearly distinguishable from find_sites and stack_breakdown without opening a schema.

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 names two alternatives with the precise conditions that select them: find_sites when combining technology with country/category/contact filters, stack_breakdown for counts, shares, or the inverse 'which X do these sites use' question. Nothing is left to inference.

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