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

Annotations already declare read-only, idempotent, non-destructive behavior, so the safety profile is covered. The description adds real value beyond them: a fixed result cap of 15 (no pagination to manage) and deterministic descending datetime ordering, which lets an agent reason about the response shape.

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 the core fact (15 latest quakes, ordering) in one efficient sentence. The trailing "Source: BMKG." partially duplicates the BMKG mention already in the first sentence, a minor redundancy.

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 zero-parameter tool with no output schema, the agent still lacks any hint of what each record contains (magnitude, depth, coordinates, region, tsunami flag). The description covers invocation adequately but leaves return-content comprehension to guesswork.

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 semantics to document; baseline is 4. The description correctly implies no filtering inputs are needed.

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 concrete verb and resource ("Get the 15 latest earthquakes"), plus scope (Indonesia, BMKG) and sort order. It only implicitly separates itself from siblings like gempa_history and gempa_dirasakan; naming those explicitly would make selection unambiguous.

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?

"Latest" implies a current-feed use case, but the description never states when to choose this over gempa_dirasakan (felt quakes) or gempa_history (archive). The agent must infer the distinction from the sibling names alone.

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