download_course_file

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

Annotations declare readOnlyHint: true, and the description aligns with that by framing the operation as a download (side-effect is writing locally, not modifying Canvas). It adds valuable behavioral context by specifying the local-server constraint and the default save directory behavior. However, it does not mention potential file overwrite behavior or permission requirements, which are minor gaps given the read-only annotation.

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 three sentences, each with a distinct purpose: stating the action, noting the environment restriction and alternative, and providing a lookup hint. There is no redundancy or filler. It is concise and front-loaded, making it easy for an agent to quickly understand when and how to use the tool.

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?

Given the tool has three parameters, no output schema, and a read-only annotation, the description is remarkably complete. It covers the core action, the operational context (local server), an alternative (read_course_file), and a lookup method for the file_id. This is enough for an agent to successfully invoke the tool without additional guidance, especially since the schema already documents parameter details.

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?

All three parameters are fully documented in the input schema (100% coverage), so the description itself doesn't need to repeat them. It adds value by advising how to find the file_id ('Use list_course_files or list_module_items to find file IDs'), which is a practical hint beyond the schema. The course_identifier and save_directory are adequately covered by schema descriptions, so the description enhances but does not duplicate param info.

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's purpose: 'Download a file from a Canvas course to the local filesystem.' It uses a specific verb (download) and identifies the resource (course file) and destination (local filesystem). It also distinguishes itself from read_course_file, which returns content in the response, making the tool's unique role clear among siblings.

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 gives explicit usage guidance: it notes that the tool is only available on a local (stdio) server, suggests using read_course_file for content-in-response scenarios, and instructs to use list_course_files or list_module_items to find file IDs. This covers when to use, when not to use, and how to prepare inputs, going beyond typical tool descriptions.

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