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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description correctly avoids repeating those. It adds valuable behavior beyond annotations: the presigned URL expires in ~15 minutes and requires re-calling to refresh, the 'contents: null' means 'not parsed yet' rather than an error, and split-produced child files carry parentSplit metadata. These are non-obvious behaviors that help the agent use the tool correctly.

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 sentences, front-loaded with the primary purpose (metadata and presigned URL), then efficiently covers the expiry, contents semantics, and parentSplit metadata. Every sentence earns its place without redundancy. It is well-structured and scannable.

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?

With an output schema present, the description doesn't need to explain return values. It covers the essential operational details: URL expiry, refresh behavior, contents null semantics, and parentSplit metadata. The only minor gap is that it doesn't mention any limits on file size or number of requests, but these are not critical for a single-file fetch operation. Overall it is complete for its purpose.

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 100%, so the baseline is 3. The description adds meaning beyond the schema by clarifying the 'contents' parameter semantics (null means not parsed yet, not an error) and implying that re-calling refreshes the URL. This enriches the parameter understanding beyond the enum and default value in the schema.

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 action: 'Get a file's metadata and a fresh presigned download URL', and optionally parsed contents. It clearly identifies the resource (a file) and the outputs (metadata, URL, contents). It distinguishes from siblings like list_files (which lists files) and parse_document (which parses) by focusing on a single file's details. The title reinforces the purpose with a clear verb and resource.

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 practical context: the URL expires in ~15 minutes and should be re-fetched, and it notes that parsed contents require running parse_document first (a sibling tool). This provides guidance on when to use this tool and prerequisites. It does not explicitly name alternative tools for fetching metadata, but the purpose is clear enough that an agent would select it when needing a single file's metadata or download URL.

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