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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds one useful behavioral fact — results are scoped to the linked Market Brew account's visibility — but says nothing about return shape or aggregation semantics.

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?

Two short sentences with the usage trigger front-loaded and no filler. The first sentence is close to a restatement of the title, which keeps it just under full marks.

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 no-required-param counting tool with full annotation coverage and a fully documented schema, the description covers purpose and the account-visibility constraint. There is no output schema, but the aggregate nature of a count makes return details largely self-evident.

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%, and the single nested 'query' object already enumerates all supported filters (customerId, crewIds, websiteId, serverHost, startDate, endDate). The description adds no parameter-level meaning, 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 (count) and resource (visible Crew accounts), which cleanly separates it from get_crew, get_current_crew, and list_crew_websites by implying an aggregate rather than a single record or list. It does not explicitly name those siblings, so it falls short of a 5.

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?

"Use this when the user asks to count visible Crew accounts" is a usage trigger, but it essentially restates the purpose rather than contrasting with alternatives. No when-not conditions or sibling routing are given, so the guidance is implied at best.

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