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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile needs no restating. The description usefully adds what the operation produces (a four-tier grade plus practical advice), which is behavior beyond the annotation set.

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 sentences, zero filler, trigger condition front-loaded before the effect. Nothing is repeated between the sentences.

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?

A simple read-only, closed-world tool with three required numeric params and full schema coverage; an output schema exists, so return values need no explanation. The description still names the grade tiers and the actionable advice, leaving nothing an agent needs in order to call it 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% and each property already documents its unit (ms, Mbps), so the schema carries the parameter burden. The description merely echoes 'download/upload speed and ping numbers' without adding expected ranges, units nuance, or a note on which measurement source to use.

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?

Names a specific verb (grades) and resource (connection quality) and states the output scale (Excellent/Good/Fair/Poor). It implicitly separates itself from measurement siblings like run_speed_test and measure_latency by grading numbers the user already has, but it never names those alternatives explicitly.

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 opening clause gives a concrete trigger: the user supplies download/upload/ping numbers and wants a verdict. That is a clear usage condition, though it gives no exclusion rule for the case where numbers do not yet exist (where run_speed_test would be the right sibling).

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