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

The description discloses rich behavioral traits beyond the annotations: data update frequency (~5 minutes), coordinate system (WGS84 geographic, not geomagnetic), and the conditional return behavior (local probability, Kp needed, go/no-go verdict with coordinates; global metadata without). These details are not present in the annotations (readOnly, openWorld, idempotent) and significantly aid correct invocation and interpretation. No contradiction with annotations.

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 description is four sentences with no redundancy. It front-loads the core function in the first sentence, then methodically explains parameter modes, update frequency, and coordinate system. Every sentence earns its place, and the structure is easy to parse for an agent.

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?

The description is complete for a tool of this complexity: it covers the data model, parameter behavior, output types, update frequency, and coordinate nuance. The output schema exists (as indicated), so return structure is handled elsewhere. Nothing an agent needs to call the tool correctly is missing.

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 schema already provides full descriptions for latitude and longitude (ranges, degrees). The description adds essential semantics beyond the schema: that coordinates are geographic (WGS84) not geomagnetic, and that providing both together triggers local lookup while omitting them returns global metadata. This complementary meaning raises the score above the baseline of 3.

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 (get), resource (OVATION model aurora forecast), and detailed scope: a global grid of aurora probability percentages at 1° resolution for the next 30–60 minutes. It clearly distinguishes from sibling tools (alerts, conditions, kp index, solar activity, solar wind) by naming the exact phenomenon and data. The two operational modes (with/without coordinates) further clarify the tool's function.

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 description implies when to use the tool: when an aurora forecast is needed, and the parameter modes (with coordinates for local probability, without for global metadata) are explicitly described. However, it does not explicitly name alternatives or state when not to use this tool versus siblings, though the purpose is so specific that an agent can infer the correct selection. The absence of explicit exclusions prevents a 5.

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