browser_focus

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the agent knows this mutates page state without being 'destructive'. The description adds one genuine behavioral detail — that focus may trigger focus-dependent UI changes (menus, validation, scroll) — but says nothing about what happens with non-focusable elements or timing.

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?

A single compact sentence with the action front-loaded and no wasted words. Nothing could be trimmed without losing 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?

With no output schema and both required parameters well documented, the description is minimally sufficient. It could go further by stating what occurs on failure or whether the tool waits for the element, but it covers enough for a simple two-param browser action.

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 100%: both selector and session_id are documented in the schema itself, including that session_id comes from browser_navigate. The description adds no further parameter meaning, so the baseline 3 applies.

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 names a specific verb and resource ('Move focus to an element') and adds a consequence ('triggering focus-dependent UI changes'), so the action is unambiguous. It does not, however, distinguish itself from the many adjacent interaction siblings such as browser_click, browser_hover, or browser_press_key, which an agent may confuse with focusing.

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 focus versus clicking, hovering, or typing into an element. The description implies the purpose but offers no conditions, prerequisites, or exclusions relative to the sibling interaction tools.

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