download_activity

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds real value by noting the payload is ZIP bytes that is not extracted, and by flagging that date and parameter limits follow the official API — but it never states those limits, size caps, or auth requirements, so the added context is thin.

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?

Short overall and the core purpose is front-loaded, but the 'one-to-one with the official client' sentence and the parameter-limit sentence consume space without conveying actionable detail, and the description mixes Chinese and English phrasing of the same point.

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 fetch with no output schema, the description covers the essentials an agent needs: what is fetched, that the result is raw ZIP bytes, and that vendor limits apply. The remaining gap is the undocumented activity_id format, which is a schema issue more than a description issue.

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 0% for the single required parameter: activity_id is an untyped anyOf(integer|string) with no description. The description's only compensation is the vague claim that parameters follow the official interface, which does not tell the agent whether to supply a numeric ID or a string, or any format expectations.

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 and resource: '下载原始运动文件' (download the raw activity file) and clarifies the return is ZIP bytes, not extracted content. This distinguishes it from get_activity / search_activities, which return metadata rather than a raw file, though the differentiation is implicit rather than spelled out.

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?

'与官方客户端 download_activity 一一对应' plus '参数和日期限制沿用官方接口' tells the agent this mirrors the vendor's own endpoint, but gives no explicit guidance on when to pick this over get_activity, nor on what those date limits or parameter constraints actually are. Usage must be inferred.

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