browser_focus

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

No annotations and no output schema, so the description carries the full behavioral burden, yet it discloses almost nothing: no error behavior when the selector does not match, no waiting/scrolling behavior, no note on whether tab_id defaults to the active tab, and no side effects (e.g. whether focus triggers blur events on the previously focused element).

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?

One short, front-loaded sentence with no padding, which is good. But at this length it reads as under-specification rather than genuine conciseness — nothing was trimmed because nothing was ever added.

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 no-annotation, no-output-schema, 2-parameter browser mutation tool, the description leaves out error handling, targeting scope, tab selection, and interaction with related tools like browser_blur and browser_click. An agent cannot call this confidently in edge cases.

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 and it does not: 'selector' is only implied by the phrase 'the matched element' with no syntax or matching rules, and the optional 'tab_id' parameter is never mentioned at all or explained as a default-to-active-tab behavior.

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 ('move focus') and a specific target ('the matched element'), so an agent can tell it apart from browser_blur, which does the opposite. It does not, however, differentiate itself from other element-targeting siblings by noting what 'matched' means (a CSS/XPath selector resolved at call time).

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 on when to use this versus browser_blur, browser_click (which also focuses), or browser_highlight. No prerequisites such as requiring the tab to be active or the element to exist. The agent must infer all of this from the name.

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