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

Annotations only declare readOnlyHint=true and openWorldHint=false; the description goes well beyond that by disclosing the cost model (1 prepaid credit per call), the required 'Authorization: Bearer <key>' header, and the exact failure mode (402 payment_required with buy links). That is exactly the behavioural context an agent needs before spending credits.

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?

One dense sentence block that is front-loaded with usage, then Inputs, Output, and Cost in a predictable order. Every clause earns its place, though the cost/payment detail could be a separate sentence for readability.

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?

There is no output schema, and the description fills that gap by enumerating the returned fields (date, source, title, summary, tags, link). Combined with the auth/cost disclosure and full parameter semantics, an agent has everything needed to call this 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?

Schema coverage is 67% (limit is undocumented in-schema) and the description compensates by giving limit's range and default ('1-20, default 5') plus concrete topic examples ('trade', 'export control') and the since format (YYYY-MM-DD). It adds real meaning over the schema, though it does not explain how topics are matched (substring vs. tag equality).

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 ('brief a foreign business on recent official Chinese regulations and policy releases') and narrows the sources to State Council English releases and MOFCOM. The sibling set (visa eligibility, pricing, capabilities) is clearly unrelated, so the agent can route here without ambiguity.

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?

Opens with an explicit use case ('Use to brief a foreign business on...') which gives clear context for invocation, and points to get_pricing for the credit/payment path. It stops short of naming when NOT to use it or which alternative to prefer for non-China or non-official sources.

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