wb_fill

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

With no annotations, the description carries the full burden, and 'clear-and-fill' is the one genuinely useful disclosure: pre-existing content is destroyed. Beyond that it is silent on whether input/change events are dispatched, what happens on non-fillable elements, error/failure behavior, and the timeout semantics. Substantive but far from complete.

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 sentences, zero padding, with the verb and eligible element types front-loaded. It stops short of being too terse to be useful, though the second sentence is closer to a schema echo than new information.

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 6-parameter tool with a nested target object containing seven sub-properties, no annotations and no output schema, the description covers almost none of the surface an agent must reason about: target-object precedence, session overriding, timeout bounds, and failure modes are all undocumented.

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 coverage is 67%, so baseline is 3. The description reinforces the selector format ('@e or CSS'), but the schema's own selector description already says 'use selector OR target', so the added value is marginal, and the 7-property nested 'target' object (ref, role, name, exact, within, snapshotId) gets no explanation from the description.

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 verb ('Clear-and-fill') and a specific resource scope (input/textarea/contenteditable), which is more concrete than the bare name wb_fill. It does not name the nearest sibling (wb_type) to draw the boundary, so it falls short of 5.

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?

There is no guidance on when to use this instead of wb_type, wb_select, or wb_press_key, and no stated prerequisites such as the element needing to be focused or visible. The only directive-like text ('selector = @e or CSS') is a parameter format hint, not usage guidance.

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