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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds no behavioral context beyond that: it does not say whether counts are time-bounded, scoped to the caller's team, or what aggregation window applies.

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?

A single compact sentence with no filler, and the key information (grouping dimensions, conversion count) is front-loaded. It is a grammatical fragment rather than a complete statement, which slightly reduces clarity for negligible length savings.

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 no parameters, the description is the only source of information about the return value, and it only sketches it ('leads by status and origin, and how many became students'). Field names, totals, and whether the shape is a flat list or nested map remain unspecified, so an agent can pick the tool but cannot anticipate its output.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. No parameter documentation gap exists.

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 names the resource (leads) and the two breakdown dimensions (status, origin) plus the conversion count to students, which tells an agent this is an aggregate stats tool rather than a list. It does not explicitly name the siblings it differs from (list_leads, get_lead), leaving that inference to the agent.

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?

There is no when-to-use guidance and no mention of alternatives such as list_leads for raw records or get_lead for a single lead. The agent must infer from the noun phrase 'stats' that this is the overview/aggregation path.

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