Get latest solar/geomagnetic indices

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

No annotations are provided, so the description carries the full burden. It clearly communicates a read-only retrieval (verb 'Returns'), lists what is returned (SFI, Kp, A-index) and includes provenance (NOAA timestamps). It could further disclose data freshness/availability, but for a simple getter it is adequately transparent. No contradiction.

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: the first front-loads the purpose and output; the second provides usage triggers and a definitive alternative. Every word earns its place, and there is no redundancy with schema or sibling titles.

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 tool with no output schema and no annotations, the description fully covers what the agent needs to select and invoke it: it defines the return content, units, timestamps, and clarifies the use case versus the sibling tool. No gaps remain.

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 has zero parameters, and the schema is an empty object. The schema_description_coverage is effectively complete, so the baseline is 4. The description adds no parameter detail because none is needed.

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 opens with 'Returns the latest raw space-weather indices used for HF propagation assessment' and enumerates the exact indices (SFI, Kp, A-index) with units and timestamps. This is a specific verb+resource, and it clearly distinguishes from sibling get_band_conditions by positioning this tool as raw numbers vs interpretation.

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 explicitly states when to use: 'Use this when asked for ''the solar flux number'', ''current Kp'', ''today''s A-index'', or when you need the raw numbers rather than a band-by-band interpretation' and names the alternative tool: 'for that, use get_band_conditions instead'. This is exemplary when/when-not guidance.

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