click_mark

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

No annotations provided, so description fully carries burden. Explains execution details: uses JS engine for web, AX tree for native, fallback to center click. Clarifies background behavior and staleness. No contradiction with parameters.

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?

Well-structured with key info front-loaded. Slightly wordy but every sentence adds value. Could be trimmed slightly but still effective.

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?

Covers all behavioral aspects: how click is performed, background option, staleness handling, fallback. No output schema needed. Agent has sufficient info to use correctly.

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%, but description adds significant context: marks come from screenshot(marks=true), staleness warning, and explanation of background parameter's effect on fallback.

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?

Clearly states it activates an element by mark number from a screenshot, contrasting with coordinate guessing. Differentiates from sibling click tools by using marks.

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?

Tells when to use (with valid mark), when mark goes stale (take fresh screenshot), and what to do if number unknown (re-shoot). Does not explicitly name alternative tools but context implies superiority over coordinate clicks.

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