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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing the payment model ($0.01 USDC per successful call on Base), the required x402-capable wallet client, the 50-item release cap, and the 90-day window limit. These are exactly the operational facts an agent needs before attempting a call.

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 tightly packed sentences, each earning its place: capability and limits first, scope exclusions second, cost/auth last. Nothing redundant and nothing buried.

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?

With no output schema, the description does convey that results are 'summary events' and bounded in count, and it covers cost and auth. It stops short of describing sort order or the fields returned, which would help an agent reason about downstream use, but nothing critical for invocation is missing.

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 description coverage is 100%, so the schema already documents startDate/endDate semantics, the 1-50 maxItems range, and the minMagnitude bounds. The description's mention of the same limits adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb (Read) and resource (USGS earthquake summary events) plus hard scope limits: 50 items, 90-day window, optional minimum magnitude. An agent immediately knows what it gets and what it does not get ('no event detail products or contact data').

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?

Clearly frames the required inputs (an explicit date window) and an optional filter (min magnitude), and explicitly excludes detail/contact data, which tells the agent when this tool is the wrong choice. No named alternatives, but the sibling set is entirely different data domains, so alternatives are not really needed.

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