download_file

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

Annotations declare a non-read-only, open-world, non-idempotent but non-destructive operation; the description adds the important detail that output lands in the user's local download folder, that there is a 200 MB ceiling, and that the result reports the file location. It does not mention overwrite behavior for duplicate filenames or what happens when the size limit is exceeded.

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?

Four short sentences, front-loaded with the action and its main constraint (size limit, destination), then the input restriction, then the return value. Nothing is redundant.

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 one-parameter tool with no output schema, the description covers destination, size limit, input provenance, and the shape of the result. Error behavior and duplicate-file handling are unstated but are peripheral to correct invocation.

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 file_url parameter, so the description must carry the semantics — and it does, by constraining provenance to get_course_materials and ruling out external hosts. It still doesn't state the expected URL format or how to obtain the value beyond naming a sibling tool, leaving a small gap.

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 (downloads LMS files) plus concrete scope: saved to the user's download folder with a 200 MB cap. It also implicitly separates itself from siblings like get_file_link and read_file_text by describing an actual file transfer to disk.

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?

Gives a clear precondition — file_url must originate from get_course_materials — and explicitly excludes external links such as Google Drive or YouTube. It stops short of stating when to prefer this over read_file_text or get_file_link for the same file, so the sibling routing is only partially resolved.

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