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

Annotations already declare read-only and idempotent behavior, so the description's added value is in disclosing data cadence, publication timing, verified freshness, units (100-million USD/SDR), the gold-value-plus-ounces detail, and the convenience *_usd_billion field. This is exactly the behavior context the schema and annotations do not carry.

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?

The description is dense and every clause adds scope, units, or freshness verification. It is somewhat long and could be broken into structured bullets, but it contains no filler.

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?

With no output schema, the description compensates by enumerating return categories, the exact unit convention, and the convenience conversion fields. The single optional parameter is fully documented in the schema, so an agent has enough information to invoke and interpret results correctly.

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 input schema already fully documents the single optional months parameter with default and max, so description-level parameter help is unnecessary. The description's unit and field-naming details concern outputs rather than parameter semantics, so the baseline of 3 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 (China's official reserve assets from SAFE) and enumerates included sub-items (FX reserves, SDR, gold, etc.), clearly differentiating it from siblings like china_balance_of_payments or china_external_debt. It lacks an explicit retrieval verb such as 'returns' or 'fetches,' but the resource and scope are 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?

It states the data frequency (monthly), the publication latency (~one week after month-end), and the source, giving an agent a clear context for when to call it. It does not explicitly compare against china_safe_releases or other siblings, but no exclusion is needed because the data scope is highly specific.

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