last_quake

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

Annotations already establish readOnlyHint=true and openWorldHint=false, so safety is covered and the description adds genuine operational context: PRELIMINAR reports appear in ~5 minutes, results may be revised, and `preliminary` preserves the first estimate. This latency/revision behavior is not derivable from annotations or schema.

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?

Front-loaded with scope, then user-intent triggers, then the caveat and field guidance. Every sentence contributes distinct information (scope, triggers, staleness handling, revision semantics) with no padding.

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 carry return-value burden; it explains the two most decision-relevant fields (`ago`, `preliminary`) and the revision model. Coverage of the full response shape is partial, but the critical caveats for correct use are present.

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?

The tool takes zero parameters, so there is no parameter syntax to explain; baseline for a no-arg tool is 4. The description instead directs attention to the fields to inspect in the result (`ago`, `preliminary`), which is more useful than param documentation would be here.

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?

Names a specific resource and scope: 'the single most recent earthquake reported by the IGEPN, with its latest (revised if available) values.' The word 'single' implicitly separates it from the sibling latest_quakes (plural list), but no sibling is named explicitly, so an agent must infer the routing.

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?

Gives concrete trigger phrases ('what was that earthquake just now', 'did it just shake?') and tells the agent what to do when the result is stale: check `ago` and say the report may not exist yet rather than guessing. It stops short of naming latest_quakes as the alternative for multi-event lookups.

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