safari_fill

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 discloses the important event-dispatch behavior and the non-error no-match result ('Returns found=False (not an error) if nothing matched'). It does not mention multi-match behavior or whether the previous value is overwritten, but the core safety-relevant behavior is covered.

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, front-loaded with the core action, no filler or redundancy. Every clause adds useful information: target element type, selector mechanism, event behavior, and no-match return semantics.

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?

The description is strong for a simple action but is not fully complete given there is no output schema and no annotations. It explains the failure case ('found=False') but not the success return shape, and it does not state behavior when multiple elements match the selector or how tab/window targeting works.

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 for parameter meaning. It adds the critical clarification that selector is a CSS selector and that value is set on an input/textarea, but it does not explain the optional tab and window parameters at all. This partial compensation merits a 3, not higher.

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 uses a specific verb ('Set') and names the resource ('<input>/<textarea>'s value') plus the mechanism ('via a CSS selector'). It clearly distinguishes itself from siblings like safari_click, safari_read, and safari_js by explaining exactly what action it performs.

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 clear context for when this tool is appropriate: 'dispatching real input/change events so JS-framework-backed forms (React, Vue, ...) observe the change' implies it should be used over raw JS injection for framework-managed inputs. It does not explicitly name alternatives or exclusions, so it stops short of a 5.

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