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

With no annotations, the description carries the transparency burden. It discloses the data source (USGS), the returned fields (magnitude, depth, tsunami flag, felt reports), and the free status. However, it doesn't address rate limits, error behavior, or whether the data is live, leaving some ambiguity.

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 first two sentences are efficient and directly relevant. The third sentence about the paid API is a tangential commercial note, not essential for using this tool, but it's short. Overall, it's concise but not perfectly focused.

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 simple read-only query tool with 5 self-documented optional parameters, the description covers the purpose, scope, and output content. It doesn't need to explain return format since no output schema exists, but it could mention default behavior (though schema has defaults). Overall it's sufficient.

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?

All 5 parameters are fully described in the schema (100% coverage), so the description doesn't need to add much. It does reinforce that 'location' is a named place and allows radius search, but provides no additional semantics beyond the schema.

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 clearly states the tool retrieves recent earthquakes from the USGS feed, with options for worldwide or radius-based search. It uses a specific resource and scope, distinguishing it from sibling tools like geocode or elevation.

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 gives clear context: use for recent earthquake data, either globally or near a named place. It doesn't explicitly exclude alternatives, but its distinct domain makes the usage context obvious.

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