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

No annotations exist, so the description carries the full burden. It weakly signals an auth tier via "PRO" (consistent with the access_token parameter), but says nothing about how recent "near-realtime" actually is, whether results are cached/delayed relative to JMA, rate limits, or how many records come back by default.

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?

A single short sentence with the resource and the upstream source front-loaded; nothing is padded. The "PRO" prefix is terse but carries real meaning about access tier, so the brevity is not waste — the problem is missing content, not excess.

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?

For a two-parameter data-feed tool with no annotations and no output schema, the description should say what a returned item contains (magnitude, location, time), how fresh it is, and what limit defaults to. None of that is present, so the agent must guess at result shape and volume.

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 50%: access_token is documented in the schema, but limit has no description anywhere. The description does not explain what limit bounds (count of events? JSON keys?) or its default/max, and "PRO" only obliquely explains the token parameter, so it fails to compensate for the coverage 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?

"Recent felt earthquakes via P2PQuake (code 551)" names the resource, the upstream source, and the feed's nature, which is more than a tautology. But there is no verb, and the description never distinguishes this from the sibling latest_quakes, which sounds like it returns the same thing; an agent cannot tell which one to call first without opening both schemas.

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?

"Useful near-realtime mirror of JMA reports" hints at a freshness-oriented use case but gives no explicit when-to-use, when-not, or alternative. Nothing tells the agent whether this or latest_quakes/quake_search is the right entry point for a given query.

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