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

Annotations only declare the generic profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false, idempotentHint=false), while the description adds the operationally critical facts: the page is one-time, the link expires in 1 hour, the file is retained 24 hours, the size cap is 25 MB, the call is free, and the agent cannot perform the upload itself. These are exactly the behaviors a caller would otherwise get wrong.

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?

Purpose, consumers, formats and size limit are front-loaded in the first sentence, followed by the interaction protocol and then the lifetime/cost facts. Dense but every clause carries information; the long compound sentences are the only mild cost to readability.

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 zero-parameter tool with an output schema, the description supplies everything an agent needs: what triggers its use, the human-in-the-loop protocol, the shell-client alternative, and the expiry/retention constraints. No material gap remains.

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 tool takes zero parameters, so the baseline is 4 and there is no parameter semantics to clarify. The description usefully frames the output ('It gives the file_id to pass to them'), even though a full output schema already exists.

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?

States a specific verb and resource ('a one-time page where the user uploads a file') and enumerates exactly which sibling tools consume it (image tools, scan_document, word_to_pdf) with accepted formats. An agent can distinguish it from every sibling without opening a schema.

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?

Gives explicit when-to-use (tools that need a file), an explicit constraint ('you cannot hand over a file from this chat yourself'), the step-by-step flow (give link, ask user to open and choose, continue when they confirm), and an explicit alternative path (upload_command in shell-capable clients). Nothing is left to inference.

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