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

Annotations already cover read-only, non-destructive, idempotent behavior. The description adds useful behavioral context: it returns the full Kp series with timestamps, includes linked CMEs/shocks, and explains what different Kp levels mean for aurora visibility, going beyond the schema.

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 compact yet information-dense, front-loading user intents and then layering authoritative context, Kp thresholds, and linked CME/shock behavior. Every sentence earns its place and there is no redundant restatement of the tool name or title.

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 adequately explains what is returned: storm events, full Kp series with timestamps, and linked CMEs/shocks. Combined with the 100% parameter schema coverage and annotations, an agent has enough context to select and call the tool, though a tiny bit more detail on response shape would make it fully complete.

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 baseline is 3 Gang. The description adds value by giving concrete meaning to Kp values (5 minor, 7 northern US aurora, 8-9 severe), which helps an agent choose an appropriate min_kp. It also reinforces the date-range filter through examples, complementing the schema.

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 uses specific verbs and a clear resource: it returns geomagnetic storm events from NASA DONKI with observed Kp index readings and timestamps. It also distinguishes itself from flare-related tools by asserting it is authoritative for actual magnetic-field disturbances rather than flare occurrence.

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 natural-language questions ('Was there a geomagnetic storm?', 'will there be an aurora tonight?') and the Kp threshold examples clearly indicate when to use this tool. It also implies a when-not by contrasting with flare events, though it does not explicitly name sibling tools as alternatives.

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