fx_upload

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It reveals the raw-path sendKeys mechanism and the root-path restriction, which are useful, but it does not mention side effects (e.g., triggering change events), prerequisites, or failure modes for non-file inputs.

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 a single sentence with the action front-loaded and the constraint separated clearly. It is concise, though the parenthetical 'raw-path sendKeys' is slightly cryptic.

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?

Given no annotations, no output schema, and three opaque parameters, the description is insufficient. It only covers the action and path constraint, leaving ref and selector semantics unexplained, which are likely essential for calling the tool.

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 0% and the description only clarifies 'path' via the root constraint. The 'ref' and 'selector' parameters remain completely unexplained, leaving the agent without the meaning or relationships needed to invoke the tool correctly.

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 states a specific action ('Set a file input value') with a clear resource (file input) and a technical hint ('raw-path sendKeys'). It is distinct from siblings like fx_type or fx_click, which handle typing or clicking, not file input assignment.

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 gives an important constraint ('path must be under FX_MCP_FILE_ROOTS') but does not explicitly state when to prefer this tool over alternatives like fx_type. Usage context is implied by the purpose rather than stated directly.

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