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

With no annotations provided, the description carries the behavioral disclosure burden. It discloses what the tool returns (metadata and download instructions), how authentication works for each URL type, and the 1-hour validity of signed URLs. It also states a key limitation (no file bytes), which is valuable behavioral context beyond the bare schema.

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 tightly written sentences with no wasted words. It front-loads the core purpose, immediately gives the essential download mechanics, and ends with a clear limitation. Every sentence contributes actionable information.

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 simple two-parameter metadata tool, the description covers core behavior, download options, and a usage warning. However, the complete lack of parameter-level explanation, especially the token parameter, leaves a meaningful gap. There is no output schema either, so the description is close to sufficient but not fully complete.

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 description coverage is 0%, so the description must compensate for the lack of parameter documentation. It never explains what file_id refers to or how the optional token parameter is used by this tool. The mention of 'with Bearer' and 'without a token' relates to the returned URLs, not the input parameters, leaving the agent to guess the meaning of token.

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 states a specific purpose: retrieving file metadata and explaining how to read the file, rather than returning file bytes. It clearly distinguishes itself from file-handling siblings like upload_file and send_file by explicitly warning against byte dumping. The resource and scope are immediately evident.

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 concrete download instructions: use download_url with Bearer or signed_download_url without a token, with a validity window. It also explicitly tells the agent not to ask the tool to dump file bytes, which serves as a clear exclusion. It does not explicitly name sibling alternatives, but the provided routing guidance is strong.

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