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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, openWorldHint=false), so the description's job is to add semantics — and it does, defining the filter predicate ('uptime is currently still climbing') and disclosing that each entry carries a `url`. It says nothing about result size limits, ordering guarantees, or empty-result behavior.

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?

The distinguishing clause is front-loaded and compact. The follow-up sentence ('These are the devices that are live champions...') largely restates the preceding clause, adding a little redundancy, and the `url` detail is mild overlap with the output schema.

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 annotations covering safety, an output schema covering return values, and full schema coverage on parameters, the description supplies the one thing structured data cannot: the meaning of the 'live' filter. It is sufficient to call the tool correctly.

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 the three parameters (brand, model, limit) are already fully documented in the schema. The description adds no further syntax, casing, or interaction details beyond what structured data provides; 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?

The description names the sibling it mirrors and the precise restriction that separates it: devices that have not yet rebooted past their recorded maximum. An agent can distinguish this from `top_devices_by_uptime` and `top_devices` without opening any 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?

It clearly frames the use case ('live champions right now' vs 'historical record-holders'), which effectively routes the agent between this tool and `top_devices_by_uptime`. It stops short of an explicit when-to-use / when-not-to-use statement, but the contrast is unambiguous.

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