page_upload_file

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

With no annotations, the description carries the burden of behavioral disclosure. It adds a useful constraint about file existence and implies a mutating action, but it does not describe what happens after upload, whether the input is cleared first, or how failures are surfaced. No annotation contradiction exists.

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?

Two short sentences with no filler. The main action is front-loaded, and the key prerequisite is stated immediately afterward.

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 mutation tool with no annotations and no output schema, the description is under-specified. It lacks guidance on session/page identification, return values, post-upload behavior, and failure handling, leaving the agent to infer several important details.

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 already documents selector and file_path, and the description only reinforces that file_path must exist locally. session_id and page_id remain undocumented in both schema and description, which is a gap given only 50% schema description coverage.

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 operation: upload a file to an input[type=file] by CSS selector. This clearly distinguishes it from all sibling tools, none of which handle file uploads.

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 clearly conveys when to use the tool (to upload a file into a file input) and gives an important prerequisite: the file must exist on the engine machine. It does not explicitly mention when not to use it, but no sibling tool offers a comparable alternative.

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