Click an element

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

Annotations cover the safety profile (destructiveHint=false, idempotentHint=false, openWorldHint=true), and the description adds substantial context beyond them: cursor movement, auto-scroll, a visible click highlight in the video, possible navigation side effects, and a named failure mode (ELEMENT_OBSCURED) that names the covering element. Only retry/timeout behavior is left unstated.

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?

Three sentences, no filler, and the primary action is front-loaded ahead of side effects and error behavior. Every clause carries information an agent needs.

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, the description usefully discloses that it reports a started navigation, and it documents the main failure mode. It stops short of covering timing, retries, or what the navigation report actually contains, but is otherwise sufficient for a one-parameter click tool.

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?

There is a single parameter with 100% schema description coverage; the schema already explains the ref format and its provenance. The description adds no ref-specific semantics, 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?

States a specific verb (click) and resource (element), and the mechanism is fully spelled out: moves the visible cursor, scrolls into view if needed, and clicks. This is clearly distinguishable from siblings such as type, press, scroll, and navigate.

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 implies the precondition (a ref from the latest snapshot, per the schema) and gives recovery guidance via ELEMENT_OBSCURED, but never states when to choose click over press, type, or navigate. Usage is implied rather than explicitly framed.

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