sftp-download-file

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

The description discloses important behavioral traits beyond annotations: it streams without passing contents through model context and refuses if transferRoot is not configured. Annotations only include destructiveHint: true, so the description adds valuable context. It doesn't cover overwrite behavior, but that is in the schema; overall it provides solid behavioral transparency.

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 two concise sentences. The first front-loads the core action and a key trait (streaming, no model context), while the second covers usage guidance and a critical constraint. No waste; every sentence earns its place.

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 download tool with full schema coverage and no output schema, the description covers the purpose, usage guidance, and key behavioral constraints. It doesn't mention error cases like missing files or authentication, but those are typical and not required. The description is sufficiently complete for an agent to call it correctly.

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 100%, so the baseline is 3. The description does not add extra semantics about parameters beyond what the schema already documents. It mentions the streaming behavior but does not explain parameter-specific details or constraints beyond the schema's own 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 action: 'Download a remote file to local disk over SFTP' with the specific streaming behavior. It also distinguishes itself from the sibling tool sftp-download by specifying when to use each ('Use this for binary or large files; use sftp-download when you need to read the contents'), making the purpose unmistakable.

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?

Explicit usage guidance is provided: the tool is for binary/large files, and sftp-download is the alternative for reading contents. It also states a key prerequisite (the destination must be inside transferRoot) and that the tool refuses otherwise, which tells the agent when not to use it.

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