toggle_overlay

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

With no annotations provided, the description carries the transparency burden. It discloses the observable effect ('interactive elements get visible numbered labels') and the relationship to get_elements() indices. It does not mention side effects or persistence, but for a reversible toggle this is acceptable.

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?

The description is three sentences, front-loaded with the core action, followed by behavioral detail and use cases. Every sentence adds value with zero 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 simple toggle tool, the description covers the purpose, effect, and appropriate use cases. The existence of an output schema means return values need not be explained. Minor gaps include parameter semantics and potential prerequisites, but overall it is adequately complete.

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 should compensate. It does not explain the 'device' or 'visible' parameters at all, though the names are somewhat self-explanatory and the phrase 'when on' hints at the visible flag. This is inadequate compensation for the missing schema 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 clearly states the action ('Toggle the numbered element overlay') and the resource ('on the device screen'). It further specifies the overlay's behavior (numbered labels matching get_elements() indices), which uniquely distinguishes it from siblings like screenshot_annotated or get_elements.

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?

It provides clear use cases: 'visual debugging or when sending screenshots to a vision model.' This gives context on when to use the tool, though it does not explicitly mention alternatives or exclusions. The guidance is sufficient for a simple toggle.

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