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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so safety and repeatability are covered externally. The description adds real context beyond that: the upstream provider (NOAA SWPC), the fixed 72-hour lookback, the free/cleared licensing status, and a mandatory attribution obligation the agent may need to surface in its answer.

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?

One tight paragraph with the usage trigger front-loaded, followed by scope, then licensing and attribution. Nothing is redundant; even the licensing clause carries operational weight because attribution is required.

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?

For a zero-parameter read-only tool with no output schema, the definition covers source, scope and what is returned (G/R/S scales plus recent alerts), which is what an agent needs to decide and call. The shape of the returned scale values is left implicit, a minor gap that a schema could have closed.

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 no parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description instead spends its words on data provenance and time scope, which is the right allocation.

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 a specific resource (NOAA SWPC geomagnetic G, radio-blackout R and solar-radiation S scales) with a defined scope (last 72 hours plus recent alerts), which is enough for an agent to distinguish it from terrestrial-weather siblings like get_severe_weather or get_natural_events. It stops short of explicitly contrasting itself with those siblings, but the domain is unambiguous.

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?

"Use this when you need NOAA SWPC geomagnetic... scales" supplies a clear positive trigger and the 72-hour window frames the context of use. No when-not-to-use condition or named alternative is given, so an agent must infer that near-Earth space-weather phenomena belong here rather than in the hazard or severe-weather tools.

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