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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it returns 'preliminary' flash figures, notes that a revised 'final' figure follows in the next monthly cycle, and mentions the 1-week lag. It also discloses that `available_months` appears in the response, which helps set expectations about the linked range. Minor gap: it doesn't describe pagination or exact response shape, but that's not critical for a single-month summary 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?

The description is dense but well-organized: it front-loads the core purpose and metrics, then covers the parameter, the lag, and the revision behavior. The Chinese translation at the end is a minor addition but not harmful. Every sentence earns its place, and the key scoping information appears early.

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 single-parameter, read-only tool with no output schema, the description is quite complete: it states the data source, the units, the metrics, the default behavior, the lag, and the revision cycle. It could be slightly more explicit about what the response contains beyond `available_months` (e.g., the actual trade values and percent changes), but the description already names those metrics, so an agent can infer the response shape. The lack of an output schema is partially mitigated by the description's enumeration of the returned metrics.

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?

Schema coverage is 100% and the only parameter (`month`) is fully documented in the schema with format and omission behavior. The description adds extra meaning by explaining the default behavior ('Defaults to the latest published month') and the range constraint ('within the currently-linked range'), which goes beyond the schema's 'Omit for the latest published month.' This is a solid baseline-plus contribution.

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 states a specific verb ('summarize'/'returns') and resource ('China's total monthly merchandise trade'), and enumerates the exact metrics (exports, imports, balance, USD/CNY, MoM/YoY changes). It also distinguishes itself from siblings like china_trade_by_commodity and china_trade_by_country by focusing on total trade, so an agent can tell it apart.

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 description explicitly says when to use it: defaults to the latest published month, and pass `month` for an earlier one within the currently-linked range. It also names the source (GACC preliminary flash release) and the lag (roughly 1 week after month-end), which helps an agent decide if this is the right tool versus a revised/final figure or a commodity/country breakdown.

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