upload_file

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

With no annotations provided, the description fully carries the burden of behavioral clarity. It explicitly discloses the CDP mechanism, event triggering, path requirements, failure conditions (file not found, element not found, non-file input) with ok:false, and scoping to the current attached tab. This is exceptionally transparent.

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 and front-loaded with an example, followed by necessary technical details. Every sentence provides useful information — mechanism, parameter types, error behavior, and scope — without excess. It is well-structured and efficient.

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 2-parameter tool with no output schema or annotations, the description covers usage, constraints, failure cases, and environment context. The only gap is that it does not explicitly describe the success return format (only mentions ok:false on failures), but it implies ok:true on success, which is sufficient for most use cases.

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 50% (path has a description, sel does not). The description compensates by giving a usage example for sel, explicitly stating path can be a single str or list, requiring absolute paths, and explaining that nodeId is resolved via query_selector. It adds meaning beyond the schema, though sel semantics are inferred rather than explicitly defined.

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's function: '给文件输入框设文件' (set file on a file input). It provides a concrete usage example and specifies the underlying CDP method (DOM.setFileInputFiles), distinguishing it from sibling tools like fill_input or type_text that handle text inputs.

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 implies the tool is for file input elements and explains behavior (triggers change event, requires absolute paths, fails on non-file inputs). It gives clear context but does not explicitly exclude alternatives or mention when not to use it, so a perfect score is not warranted.

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