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

Annotations already declare readOnly, idempotent, open-world, and non-destructive, so the safety profile is covered. The description adds genuinely useful cost behavior (free within daily allowance, then $0.001 USDC via x402), which is a rate/quota signal not present in the structured fields.

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, front-loaded with the core scope and followed by the pricing note. Every clause earns its place with no redundancy.

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 an output schema and full annotation coverage, the description supplies scope plus cost context, which is enough to invoke correctly. Minor gap is the absence of explicit sibling routing, but return values and safety are otherwise covered.

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 takes zero parameters, so there is no parameter semantics to document; the baseline for a parameterless tool is 4. The 100% schema coverage and empty properties object confirm nothing is left unstated.

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 precise verb-less but unambiguous resource with a clear magnitude filter (4.5+), geographic scope (worldwide), and time window (past 7 days). This cleanly distinguishes it from siblings like earthquakes__m25-day (lower threshold, 1-day window) and earthquakes__significant-week.

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 magnitude and time scope implicitly signal when this tool applies versus m25-day or significant-week, but there is no explicit when-to-use guidance, no named alternatives, and no exclusions. Usage is left to inference from the scope statement.

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