zerodom_upload_file

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

With no annotations provided, the description carries the full behavioral burden. It adds a genuinely valuable security disclosure: 'path is resolved on the machine driving the browser — the same trust boundary as zerodom_eval_js, not a new one,' which tells the agent the path is interpreted on the driver host and introduces no additional trust risk. It also discloses the return behavior ('return what changed'). It omits edge cases like invalid paths or event firing, but the trust-boundary context is significant enough to justify a 4.

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?

Exactly two sentences, both earning their place: the first conveys the action and return behavior, and the second adds a security-relevant boundary note. There is zero filler, and the primary behavior is front-loaded ahead of the caveat.

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?

Complexity is low (two required string params, no enums, no nesting) and an output schema exists, so return values need not be explained. The description covers the core mechanics and security context. However, it leaves usage routing, prerequisites (target node must be a file input), and error behavior (e.g., nonexistent path) unstated, which an agent would need for fully confident invocation.

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%, so the description must compensate. It does clarify the critical parameter: 'path' is a local file path resolved on the driver machine, adding meaning beyond the bare string type. However, 'node_id' receives no elaboration and relies on the zerodom_* sibling convention of identifying nodes. One of two parameters is well-explained; the other is left implicit, so the compensation is only partial.

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 verb and resource: 'Set a file input's value to a local file path and return what changed.' It clearly scopes the tool to file inputs and names the outcome (what changed), which distinguishes it from siblings like zerodom_fill_node (general text filling) and zerodom_eval_js (arbitrary JS execution). An agent can determine what this tool does without opening the schema.

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 scope is implied by the description: 'a file input' signals when the tool applies, and the trust-boundary sentence references the sibling zerodom_eval_js. However, the description never explicitly states when to prefer this over zerodom_fill_node, nor does it give exclusions such as 'do not use for non-file inputs.' Context is present but relies on inference rather than explicit routing.

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