download_file

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

No annotations are provided, so the description carries the full burden. It discloses the side effect of writing to local disk, the default destination folder, path traversal restrictions, and filename sanitization/de-duplication. These are material behaviors an agent needs to anticipate before invoking the tool.

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?

Three focused sentences: the main action and return value come first, followed by destination behavior and filename handling. There is no redundancy or filler.

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?

The description covers the operation, side effects, path security, and filename behavior, which is strong for a 3-parameter tool with an output schema. It does not describe error cases such as missing attachments or invalid message IDs, but those are not essential for correct tool selection and 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?

With 0% schema description coverage, the description compensates by explaining dest_dir's role and security constraints. It also relates chat and message_id to 'one message', though it does not explicitly describe chat's format or how to obtain message_id. The parameter names and context largely resolve this.

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 first sentence names the action (Download), the object (file attached to one message), and the result (path on local disk). This clearly distinguishes it from sibling tools like search_files or get_messages, which locate or retrieve data but do not download attachments.

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 makes the intended use case clear: download a message attachment to a local path. However, it does not explicitly contrast with alternatives or state when not to use this tool, so routing guidance is mostly implicit.

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