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

Annotations already cover read-only, idempotent, and non-destructive behavior, so the description doesn't need to repeat that. It adds valuable behavioral context: data is updated every minute and the service is free, which informs expectations about freshness and cost. No contradictions with 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?

The description is two sentences, concise and front-loaded with the main functionality. It includes the data source, update frequency, and cost without fluff. Every sentence earns its place.

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?

The description covers time range, filters, output fields, data source, and freshness. However, it does not explain the response format or pagination, and the time range phrasing 'last hour to 30 days' is not aligned with the actual period enum, which could mislead an agent. It also doesn't mention that limit defaults to 20 or caps at 100, though those are in the schema. Overall adequate but with notable gaps.

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 only 20%, so the description must compensate. It explains the purpose of 'near' (place or lat,lon), 'radius_km' (within a radius of a place), and 'min_magnitude' (minimum magnitude filter). It hints at 'period' via 'last hour to 30 days', but that wording is ambiguous and doesn't match the enum values (hour/day/week/month) precisely. 'limit' is not explained at all. It partially compensates but leaves gaps.

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 identifies the tool's purpose: it returns earthquake data worldwide, filtered by magnitude and optional location radius, with depth, tsunami flag, and alert level. The verb is implicit but the resource and scope are explicit, and there are no similar sibling tools to confuse it with.

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?

It provides clear context: the tool is for querying recent earthquake data from USGS, with time ranges from the last hour to a month. It implies usage for seismic activity lookups, and since no siblings are similar, explicit exclusions are unnecessary. The mention of 'USGS real-time feeds' and 'free' adds practical guidance.

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