macro_china_rmb

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered by structured data. The description contributes the historical coverage window (20170103-至今), which is genuinely useful behavioral context, but says nothing about update frequency, source refresh, or data completeness.

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 useful content is one short sentence front-loaded correctly, but the entry leaks Python docstring artifacts (`:return:` and `:rtype:`) and repeats the title, adding noise without information. A trimmed single sentence would be tighter.

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 no-parameter data-fetch tool with no output schema, the description conveys the resource and its time coverage, which is the minimum needed. It stops short of describing the returned fields (e.g., the parity rate series, currency pairs covered) or the pandas.DataFrame shape, so an agent cannot anticipate the result structure.

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 nothing for the description to disambiguate. Baseline for a 0-param tool is 4; no syntax or format gaps exist because there are no inputs.

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 specific verb+resource: it reports China's RMB central parity rate (汇率中间价) covering 20170103 to present. That is clear enough for an agent to know what the tool returns. However, it does not distinguish itself from closely named siblings like macro_rmb_deposit, macro_rmb_loan, or the currency_* tools, so the differentiation burden falls on the reader.

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?

The only usage-relevant content is the date range starting 20170103. There is no statement of when to prefer this over macro_china_fx_gold, currency_boc_safe, or the many other RMB/FX siblings, and no exclusions or prerequisites.

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