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

With no annotations, the description carries the full burden and does reasonably well: it discloses the return structure (count, largest event, magnitude/place/depth table with links), the live third-party source (USGS), and the x402 payment cost ($0.02/call in USDC on eip155:8453). It omits auth mechanics beyond pricing and any rate/latency behavior.

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?

Four sentences, front-loaded with the purpose and filters before moving to return shape, usage, and pricing. Mostly earns its place, with a small grammar stutter in 'needs to recent quakes' and a slightly redundant restatement of the USGS source.

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?

No output schema exists, but the description compensates by summarizing the returned fields (count, largest event, table with links). Combined with the pricing disclosure, an agent has enough to call it correctly; only auth/permission details beyond payment are 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 baseline is 3. The description restates the filters (region via city or coordinates+radius, min magnitude, days) and lightly clarifies the city-OR-coordinates relationship the schema also notes, but adds no units, defaults, or format guidance beyond the schema.

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 resource (recent earthquakes from USGS) with the exact filter dimensions available (region via city or coordinates+radius, minimum magnitude, look-back window). It also names the return contents, so an agent immediately knows both what it fetches and what it gets back. No sibling tool covers seismic data, so it is trivially distinguishable.

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?

Explicitly says 'Use this when an agent needs recent quakes by region and magnitude from USGS,' which gives a clear trigger. It does not name any when-not conditions or alternative tools, but no overlapping sibling exists, so the omission is minor.

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