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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety bar is low; the description still adds real value by naming the data provenance (USGS via QuakeIndex), the presence of per-result source and last-confirmed timestamps, event links, and the newest-first ordering. The one gap is that it does not disclose default behavior when no location input is supplied, despite zero required parameters.

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?

Three front-loaded sentences with the spatial and temporal scope stated first and no filler. The closing ShakeAlert/MyShake sentence is the weakest — it reads as a disclaimer rather than invocation guidance — but it does carry the meaningful 'no warnings' constraint.

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 9-parameter tool with no required inputs and no output schema, the description covers location selection and return contents adequately. It leaves open what happens with an empty call, how limit interacts with the 'largest in window' item, and how min_magnitude affects results — gaps an agent would have to guess at.

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?

With only 44% schema description coverage, the description must compensate, and it does explain the critical location-mode semantics (coordinates vs. ZIP vs. city). But it adds nothing about limit (default 20, max 50), min_magnitude, state, or the days default, all of which the schema documents thinly or not at all.

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 first sentence states a specific resource (earthquakes), a spatial filter (radius around coordinates, ZIP, or town), a temporal window (1-365 days), and the sort order plus returned content (distance, largest in window). This clearly separates it from latest_earthquakes and largest_on_record, though it never names a sibling explicitly.

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 'no predictions and no warnings' line functions as an implicit exclusion, steering the agent away from expecting alerting behavior. However, there is no explicit when-to-use vs. place_activity or latest_earthquakes guidance, and no statement about which of the three location input modes to prefer.

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