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

Annotations already declare readOnlyHint, idempotentHint, etc. Description adds that the tool returns only a count (not full data) and sources from USGS. This provides useful behavioral context beyond 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?

Single sentence with no waste. Front-loaded with the core action ('Count earthquakes...') and immediately provides the key differentiator ('without returning full data'). Exceptionally concise.

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 count query with rich annotations and full schema coverage, the description provides sufficient context: what it does, when to use it (statistics/monitoring), and the data source (USGS). No gaps identified.

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?

Input schema has 100% coverage with descriptions for all 7 parameters. Description adds no new parameter-specific semantics beyond 'matching search criteria', which is a general reference. Baseline 3 applies as schema does the heavy lifting.

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?

Description clearly states the tool counts earthquakes matching search criteria without returning full data. It distinguishes from siblings (earthquake.events.feed and earthquake.events.search) by specifying it only returns a count, not a list of events.

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?

Description explicitly says 'useful for statistics and monitoring thresholds', indicating when to use this tool over siblings (which return full data). Could be improved with explicit 'when not to use' guidance, but the context is clear.

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