download_file

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

With no annotations, the description carries the full transparency burden. It mentions the SFTP protocol and return format, but does not disclose potential overwrite behavior, directory creation, authentication prerequisites, or other side effects. This leaves some ambiguity for a file operation.

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 well-structured with Args and Returns sections, front-loaded with the core purpose. Every sentence provides necessary information without redundancy or padding.

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 tool's purpose, parameters, and return values, making it complete for a straightforward download operation. It does not cover edge cases like overwrite policy or error handling specifics, but these are not critical given the tool's simplicity and the presence of 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 description provides thorough explanations for all three parameters, adding meaning beyond the schema. It clarifies that paths are absolute and that host_name selects from SSH_HOSTS config with a default fallback, which significantly aids correct usage.

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 a file from remote to local via SFTP, using specific verbs and resources. It is distinct from siblings like upload_file, which performs the reverse operation.

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 context about the host_name parameter and default behavior, but does not explicitly mention when to use this tool versus alternatives like upload_file. However, the purpose is so specific that usage is implied.

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