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

There are no annotations, so the description carries the full transparency burden. It does disclose the 3MB limit and some chat-behavior rules, but it does not explain side effects, failure modes, permissions, or what the agent should observe after uploading. It also relies on unexplained putUrl/dropUrl terms.

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 compact two sentences and contains no filler; each instruction is directly operational. However, the brevity contributes to ambiguity because key concepts like putUrl and dropUrl are never defined.

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 is structurally poor and lacks output schema or annotations. It does not explain what the tool returns, how dropUrl and putUrl relate, or what the human is expected to do with them. For a zero-schema tool with no annotation support, the description is under-specified.

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 schema has zero parameters and 100% coverage, so semantic parameter depth is trivially satisfied. The description mentions putUrl and dropUrl, but they are not actual schema parameters, so there is no additional parameter meaning needed.

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 never clearly states what the upload_url tool actually does. It instructs the agent to "PUT putUrl yourself" and mentions dropping the URL, but it does not define whether the tool creates a URL, uploads a file, or performs an HTTP request. The purpose is implied rather than explicitly explained.

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?

It gives concrete conditional instructions: if the agent has the zip, it should PUT to putUrl, must not put the zip in chat, and should only send dropUrl to the human if no file is available. This is explicit usage guidance, though it does not compare against sibling tools.

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