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

With no annotations, the description carries the full burden, and it does disclose the commercial model (free preview vs $0.05 paid calls through x402) and that samples are 'live'. It does not cover rate limits, caching/delay of the preview data, or response shape details, which leaves some behavioral gaps for a zero-annotation tool.

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: the first front-loads exactly what data is returned, the second adds the pricing/endpoint context that determines whether to escalate. No filler, no repetition of the title.

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, no-output-schema preview tool, the description is nearly sufficient — it enumerates the four data verticals and the paid alternatives. A brief note on sample freshness/latency or response shape would close the remaining gap, but an agent can call it correctly as written.

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 the baseline is 4; the description correctly implies no input is required. Nothing in the text contradicts or confuses that empty schema.

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 the exact resource set — one live sample from each Indonesian vertical (USD/IDR, BTC/IDR on Indodax, BMKG quake, public holidays) — which is a specific verb-plus-resource statement. It also maps the paid counterparts to /fx, /crypto, /quake, /holidays, implicitly separating it from siblings like indonesia_fx and indonesia_earthquake, though it does not name those sibling tools directly.

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?

It gives an explicit trigger — 'so an agent can check freshness and shape before paying' — which is a clear when-to-use condition. The alternative path (pay $0.05/call for full versions via x402) is stated, but it never explicitly says when not to use this preview or how the seconds of latency/coverage differ.

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