browser_focus

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

With no annotations, the description carries the full burden, but it fails to disclose behavioral traits: no mention of side effects, error handling, required element visibility, or whether it scrolls to the element. The agent has no information on limitations or safety.

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 no wasted words. However, it may be too concise for the information needed; it earns its place but could be slightly more detailed.

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 the simplicity of the tool (one parameter, no output schema), the description is incomplete. It does not explain what 'focus' means, prerequisites, or potential return values. The agent is left with gaps.

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?

The schema coverage is 0%, so the description must compensate. It states 'CSS selector' which specifies the format of the 'selector' parameter, adding meaning beyond just a string type. This is valuable context for correct usage.

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 clearly states the action ('Focus') and resource ('element') and specifies the input ('CSS selector'). It distinguishes from sibling tools like 'browser_click' or 'browser_type', though 'browser_scroll_to_element' is similar but different. The term 'focus' is standard in browser automation, so the purpose is well-understood.

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?

No guidance is provided on when to use this tool versus alternatives (e.g., when needing to set focus before typing, or when dealing with keyboard events). There is no mention of contextual prerequisites or exclusions.

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