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

Annotations already declare read-only, idempotent, open-world, non-destructive behavior, and the description adds real context on top: data source (NOAA SWPC), sort order, the derived NOAA radio blackout level, and the included largest-flare summary. It also discloses a cost of 1 credit and the analytical limits of the data, though it says nothing about freshness/latency of the GOES feed.

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?

Front-loaded with the user-facing question, then the concrete payload, then the boundary/cost caveats in a single tight paragraph. No sentence repeats the title or the schema.

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 usefully enumerates the returned fields (class, begin/peak/end times, peak flux, blackout level, largest flare) and names the upstream source, which is enough to call it confidently. Minor gap: no note on feed latency or how sparse results appear on quiet days.

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 days, limit, and min_class are already fully documented; the description only echoes the day range implicitly ('last 1-7 days'). It adds no guidance on how min_class interacts with the 'largest flare' summary or how limit truncation affects that summary.

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?

States a specific verb and resource ('Lists X-ray flares detected by the GOES satellites') with concrete scope (last 1-7 days), ordering (newest first), and returned fields. It also draws the boundary against adjacent phenomena: 'covers flares only, not CMEs or whether a flare will affect Earth,' which separates it from space-weather alert or forecast siblings.

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 leading question 'Was there a big solar flare today?' frames the use case, and the closing sentence gives an explicit exclusion (no CMEs, no Earth-impact assessment). It stops short of naming which sibling to use instead for CME or impact questions, so routing is implied rather than prescribed.

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