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

With no annotations, the description carries the full behavioral burden and does well: it discloses the data source, the returned fields, and — critically — the three payment mechanisms and their prices (0.01 USDC/x402, 12 sats Cashu, 12 sats Lightning). It omits rate limits, refresh/caching cadence, and error behavior, which keeps it short of a 5.

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?

Two sentences, purpose and filters front-loaded, then return fields, then cost. No filler, and the payment detail is placed last so it does not bury the core purpose.

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 or annotations exist, so the description is the sole information source; it covers the return shape and cost model adequately. The remaining gap is lat/lon format/units and any behavioral limits, but for a read-only data-fetch tool it is nearly complete.

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 0%, so the description must compensate for all 5 undocumented params, and it largely does: 'minmag' is explained as minimum magnitude, 'period' is given its enum values (hour|day|week|month), and 'radius_km' is tied to lat/lon with a km unit. It does not specify coordinate format or units for lat/lon, leaving a small gap.

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) with its data source (USGS) and the exact filter dimensions (minimum magnitude, period, radius around lat/lon). No sibling tool overlaps with seismic data, so the agent can distinguish it immediately without opening the schema.

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 by enumerating the filters ('filter by minimum magnitude, period...'), which tells the agent how to shape a query, but never states when to reach for this tool versus alternatives or any exclusions. With no competing sibling, the omission is tolerable, but there is no explicit when-to-use guidance.

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