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

With no annotations present, the description carries the full burden and does unusually well: it discloses that the tool is metered ($0.001 per call via x402/USDC on Base) and that responses carry a provenance chain and Ed25519 attestation, which shapes agent trust decisions. It omits failure behavior for unknown ids and any latency/rate-limit context, keeping 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, zero filler, with the core lookup purpose front-loaded before the payment and attestation details. Every clause carries distinct information.

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?

There is no output schema, so the description must communicate return content, and it does by enumerating the event fields plus the provenance/attestation envelope. What remains thin is the id format and the not-found/no-charge case, which an agent would need to call confidently.

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 50%: the payment parameter is documented in the schema, but the required id parameter has no description at all. The phrase 'USGS earthquake event by event id' adds partial meaning (it is a USGS event identifier), but no format example or validation hint compensates for the gap. Baseline 3 for a half-covered schema is appropriate.

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 names a specific resource (a USGS earthquake event) and the lookup key (event id), then enumerates the returned fields (magnitude, depth, place, origin time, alert level). An agent immediately knows this is a point lookup, not a search or aggregate. It does not need to differentiate from siblings since no other quake tool exists in the sibling list.

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?

There is no statement of when to use this tool versus alternatives, nor any prerequisites or exclusions. The only usage-adjacent content is the cost disclosure ($0.001 per call), which tells the agent the call is paid but not when it is the right choice.

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