babelwrap_upload

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

With no annotations provided, the description must fully disclose behavioral traits. It only states the core action ('upload a file') but omits details such as whether the file input's value is set programmatically, whether a change event is triggered, required permissions, or error behavior (e.g., if the target element is not a file input). The lack of such information leaves the agent unaware of side effects or constraints.

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 of 10 words, conveying the essential action without any extraneous information. Every word serves a purpose, and the structure is front-loaded with the key operation. It is maximally concise while remaining clear.

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?

Despite the existence of an output schema (not shown but implied by context), the description lacks several important contextual cues: it does not mention that a session is required, that the file must be base64-encoded, or that the target should be a file input. With five parameters and multiple sibling tools, a more complete description would include at least session prerequisites and a brief note on the base64 requirement.

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?

All five parameters are documented in the input schema (100% coverage), so the baseline is 3. The description does not add any additional meaning beyond what the schema already provides (e.g., it doesn't explain how the 'target' natural language description works or how 'file_base64' should be encoded). This is acceptable given the schema's completeness.

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 'Upload a file to a file input element on the page' is very specific: it states the action (upload), the resource (file input element), and the context (on the page). The verb 'upload' clearly distinguishes this tool from other babelwrap tools like 'click' or 'fill', which handle different interactions. No ambiguity exists.

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 provides no guidance on when to use this tool versus its siblings (e.g., babelwrap_fill for text inputs). It does not specify prerequisites (e.g., an active session), nor does it mention any conditions under which the tool should not be used. This leaves the AI agent with no rationale for selection among similar tools.

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