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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the bar is lower. The description adds genuine value by spelling out what data is returned — a 24-hour freshness window, a catalog-size figure, and a ranked reliable-servers list — which is exactly the disclosure an agent needs when no output schema exists.

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, metrics front-loaded, followed by a compact usage cue. Nothing is padded and nothing repeats the title or annotations.

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 input parameters and no output schema, the description carries the return-value burden itself and lists the major fields an agent can expect. It could be slightly more explicit about whether counts are real time versus cached, but for a read-only status tool it is close to sufficient.

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 the baseline of 4 applies. There is no parameter semantics to clarify and the description correctly spends none of its text on inputs.

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 enumerates the concrete contents of a status snapshot (catalog size, servers measured, checks in last 24h, open needs, top reliable servers), which makes the resource identifiable without opening the schema. However, it never states the action in a verb+resource form and does not distinguish itself from the overlapping list_open_needs sibling, which also surfaces open needs.

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?

The 'Use when: you want to know how much Faceabot currently knows' line gives a rough intent trigger, but it is largely circular with the metric list and names no alternatives or exclusions despite obvious overlap with list_open_needs and check_reliability. Usage is implied rather than routed.

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