moodle_download_file

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

Annotations already indicate read-only, idempotent, and non-destructive. The description adds valuable behavioral detail by stating that the returned content is decoded as text ('返回内容按文本解码') and that only Moodle internal URLs are accepted. This goes beyond the annotation-provided safety profile.

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 extremely concise, consisting of two sentences. The first states the primary purpose, and the second delivers key parameter and behavior instructions without any filler. It is well-structured and front-loaded.

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 simple tool with one parameter and strong annotations, the description covers all necessary aspects: the exact URL format, the source of the URL, and the output decoding behavior. It provides enough context for the agent to use the tool correctly, even without an output schema.

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 only lists a required 'url' with format uri, but the description enriches this meaning by specifying that the URL must be a full link starting with 'pluginfile.php' and should be taken from other tool returns. This is essential additional guidance for correctly constructing the parameter, fully compensating for the lack of schema parameter descriptions.

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 clearly states the tool downloads files from Moodle, with a specific verb ('下载') and resource ('Moodle 上的文件'). It further distinguishes itself by requiring the URL to start with 'pluginfile.php' and be a Moodle internal address, which differentiates it from similar download tools like ed_download_resource.

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 provides clear usage context: use the URL returned by other tools (从其他工具的返回里拿), and only accept Moodle internal addresses. It doesn't explicitly mention alternatives, but the specificity about pluginfile.php and Moodle-only addresses effectively guides the agent on when to use this tool.

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