browser_click_at

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

With no annotations, the description carries the full burden of behavioral disclosure. It explains coordinate semantics (viewport, CSS pixels), the resolved selector fallback chain (data-testid → id → CSS path), and the updated preview. It could additionally disclose caveats like out-of-viewport coordinates or non-clickable elements, but it covers the core behavior well.

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 concise sentences: the first states the action and return value, the second provides usage guidance. No filler or redundancy.

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 two-parameter coordinate click tool, the description covers the essential behavioral contract: what it clicks, how coordinates are interpreted, what it returns, and when to use the alternative. No output schema exists, so the return value description is especially valuable and sufficient.

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 100%, so the baseline is 3. The description reinforces that x and y are viewport coordinates in CSS pixels but does not add meaningful new constraints or clarifications beyond the schema property descriptions.

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 states a specific verb ('Click'), a concrete resource ('viewport coordinates (x, y in CSS pixels)'), and the return value, which distinguishes it from sibling browser tools. It also explicitly differentiates itself from browser_run_step by indicating coordinate-based versus selector-based interaction.

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 guidance on when to prefer an alternative: 'Prefer browser_run_step with a selector for reproducible steps.' This explicitly tells the agent the situational trade-off and names the sibling alternative.

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