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 and does so richly: it discloses the pointer-movement sequence (move, then down, then up, with hold), the return value (screenshot after release), the silent-failure behavior (nothing raises, the click lands on whatever is there now), and the isolation between main and support browsers.

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?

Front-loaded with the core action and the differentiator, then the mechanics, then the staleness caveat, then the browser note. Dense and largely waste-free, though the multi-clause sentence structure is on the longer side.

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 4-param a tool with no annotations and no output schema, the description covers action, alternatives, movement sequence, return value, failure semantics, coordinate frame, and browser isolation. Nothing needed to invoke it correctly is missing.

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 0%, so the description must compensate, and it does: it defines x/y as viewport-relative (not page-relative), explains hold_seconds as press-and-hold, and clarifies browser defaults to main with no shared state between the two. Every parameter gets meaningful semantics beyond the bare schema.

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 action (click/press-and-hold at a raw viewport coordinate) and explicitly contrasts it with the selector-based approach, so the agent can distinguish it from browser_click. The parenthetical examples (slider track, canvas captcha, precise point in a wider element) sharpen the distinction further.

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?

Gives explicit when-to-use (targets a selector cannot reliably reach) and an explicit alternative with preference ordering: 'prefer browser_click with the element's selector whenever it has one.' It also names the condition that invalidates cached coordinates (anything that scrolls) and the remediation (take a fresh snapshot).

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