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

Annotations already declare readOnlyHint: true, so the description is not required to repeat that. It adds valuable behavioral context by describing the scoring scale (Extreme=4 to Minor=1), the saturating scale, and the hourly refresh cadence, which helps the agent understand what the score represents and that it changes over time.

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 exceptionally concise—two sentences that front-load the main purpose and then provide usage scenarios. Every word earns its place, with no redundant explanations or filler. The structure is easy to parse and quickly conveys the essential information.

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?

Given the simplicity of the tool (one optional parameter, no output schema), the description is remarkably complete. It lists the output fields, provides use-case triggers, and notes the update frequency. The schema covers the only parameter, so the description does not need to repeat it. This is sufficient for an agent to select and invoke the tool correctly.

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 input schema has 100% coverage for its one optional parameter, 'days', including a detailed description about the historical series and the Gold tier requirement. The tool description itself does not mention the 'days' parameter, but with full schema coverage, the baseline score of 3 is appropriate, as the schema already carries the semantic weight.

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 a strong verb 'Returns' and specifies the exact resource: a 0-100 US severe-weather warning-pressure score. It goes on to enumerate the output components (trend, confidence, top_drivers, severity breakdown, states affected, recent alerts), making the tool's function unmistakable and clearly distinguishing it from a generic weather tool.

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 provides explicit guidance on when to use the tool: 'Call when the user asks how severe the current US weather-warning load is, which states are under alerts, or about storm severity...' It covers a range of relevant scenarios, but does not mention alternatives or exclusions, leaving room for slight ambiguity in edge cases.

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