create_file_by_url

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

The description discloses a key behavioral trait: the tool rejects direct calls without an active skill grant/run descriptor, which is not captured in annotations. It also reveals that it returns an asset id for later use. Annotations only indicate non-read-only/non-destructive, so this additional behavioral context is valuable.

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 concise sentences, each adding distinct value: what it does, how to use the output, and a prerequisite/restriction. There is no filler, and the main purpose is front-loaded.

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 tool with 4 parameters and no output schema, the description covers the core action, the return value (asset id), and a critical prerequisite. It omits details on optional parameters and failure behavior, but the provided annotations and straightforward purpose keep it reasonably 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 only 25% (only url has a description). The tool description does not explain the purpose of title, purpose, or groupName, and it merely restates the url's schema description. With low schema coverage, the description was expected to compensate but does not.

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 tool materializes a public URL into a current-project asset, using a specific verb and resource. It distinguishes itself from siblings by mentioning the returned asset id for later media calls and by referencing the run_skill prerequisite, making its role unique.

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 explicitly instructs calling run_skill first and warns that direct calls are rejected without the skill grant, giving a clear precondition. It also indicates the tool's output is used in later media calls, providing context. It does not explicitly name alternative tools like web_fetch, but the usage context is well-defined.

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