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

Annotations are minimal (only title), so the description carries the burden for behavioral disclosure. It reveals the data source (USGS), the nature of the output (recent, with magnitude and location), and parameter behaviors. However, it does not explicitly state that the operation is read-only or note any limitations like rate limits or pagination, relying on the context of a query tool.

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 a single, well-structured sentence that front-loads the core purpose and then briefly explains parameter usage. Every phrase earns its place, with no redundancy or filler.

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 optional parameters and no output schema, the description adequately covers the main aspects: what data is returned (magnitude, place, how long ago), the data source (USGS), and how to customize the query. It lacks only minor details like default values, which are already in the schema.

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 coverage is 100%, so the baseline is 3. The description adds minor clarification by calling min a 'magnitude floor' and summarizing how lat/lon and period are used, but it largely restates the schema descriptions without adding significant new meaning.

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 it provides 'Recent earthquakes worldwide from the USGS, with magnitude, place and how long ago', giving a specific verb, resource, and scope. It is easily distinguishable from sibling tools like hazards_alerts, which deal with different hazard types.

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 offers parameter guidance ('Pass lat/lon to ask about somewhere in particular, min for a magnitude floor, and period for hour, day, week or month'), but does not explicitly state when to use this tool versus alternatives or provide exclusions. Usage is implied rather than clearly framed.

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