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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive hints, so the safety profile is covered. The description adds valuable behavioral context by specifying what content is returned (topics, geography, sources, freshness) and that it also states exclusions. It does not contradict 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?

Two sentences with zero filler. The core capability is front-loaded: it lists coverage dimensions and exclusions, followed by the single usage directive. Every word earns its place.

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 no-parameter tool with a rich annotation set and an output schema, the description is fully complete. It tells the agent what to expect (coverage details) and when to use it. No additional information is needed for correct invocation.

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, so the schema already fully defines the invocation signature. The description doesn't need to elaborate on parameters, and the baseline of 4 applies. It correctly implies the tool takes no arguments.

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 it lists topics, geography, sources, and freshness, and what it does not cover. This clearly distinguishes it from sibling tools that focus on specific domains (e.g., weather, votes, law), making the purpose unambiguous.

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?

Explicit usage guidance is provided: 'Call this only when unsure whether a question is in scope.' This instructs the agent when to invoke the tool and implies when not to (when certainty exists), though it doesn't name alternatives – none are needed for a coverage tool.

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