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

Annotations already declare readOnlyHint, non-destructive, idempotent, and openWorldHint, lowering the burden. The description adds useful context (100+ years of data, USGS update every minute) but does not disclose pagination behavior, rate limits, or whether combining lat/lon requires maxradiuskm. Overall, adds moderate value 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?

A single sentence that front-loads the core action ('Search global earthquakes by...'), then lists return fields and data characteristics. Every clause provides value; no wasted words. Excellent conciseness for a tool with 12 parameters.

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?

Given the tool's complexity (12 optional parameters, rich filter capabilities), the description covers the main purpose, return fields, and data provenance. However, it omits that all parameters are optional, default limit of 20, and how to combine location parameters (e.g., lat/lon requires radius). With an output schema present (confirmed), completeness is adequate but not exhaustive.

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 and detailed descriptions for all 12 parameters. The description merely mentions the categories (time, location, magnitude, depth) without adding new semantic meaning. Baseline 3 is appropriate since schema already 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?

The description uses a specific verb-resource combination ('Search global earthquakes') and lists exact return fields (magnitude, coordinates, tsunami flags, PAGER alerts, felt reports). It also provides data scope (100+ years, updated every minute by USGS), making the tool's purpose crystal clear and well-differentiated from vague alternatives.

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 implies usage for detailed searches with various filters, but does not explicitly compare with siblings like earthquake.events.count or earthquake.events.feed. No 'when to use' or 'when not to use' guidance is provided, leaving the agent to infer context from the tool name alone.

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