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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuinely new behavioral facts: the run-detection window, the 8-hour minimum threshold, and the null semantics of suggestion ('or null when the current size is needed or that run holds less than 8 hours'). It does not describe the histogram bucket format, units, or response size, which is the main remaining gap.

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?

Purpose and return content are front-loaded, then the actionable guidance follows, and roughly 110 words is proportionate for a tool with seven distinct returned series. The first sentence is a long run-on enumerating metrics that is harder to parse than it needs to be, but nothing 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?

With no output schema, the description carries the return-value burden and does so thoroughly: elapsed play time, the six histogram series, and the suggestion field including its null conditions. Safety is covered by annotations and the mutation path is spelled out, leaving nothing an agent needs in order to call and interpret it.

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 reported as 0% at the top level, and the description says nothing about the path/serverId parameter or where to obtain it. The nested schema does carry a usable hint ('the id field from listServers'), so the agent is not stranded, but the description itself contributes no parameter meaning — a baseline 3 for a single obvious parameter.

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 states a specific verb and resource ('Returns the time the server spent with at least one player online...') plus the exact aggregation window ('latest unbroken run... last 7 days with players, or more days back until they hold 8 hours'). It implicitly separates itself from getServerMetrics by framing the result as a sizing analysis with a suggestion field, but it never names that sibling, so an agent must infer the distinction.

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 gives an explicit consumption instruction ('Use suggestion to answer whether the server can run on a smaller size') and routes the follow-up mutation to the correct sibling ('changing size is updateServer with the target size and applies on the next start'). There is no explicit when-not-to-use statement relative to getServerMetrics or getPricingCatalog, which keeps it below a 5.

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