full_screen

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=true, so the description adds almost nothing beyond them. It never explains what calling it while already fullscreen does, nor how the toggle state is reported, and 'toggles' sits in slight tension with the idempotent hint since toggling twice restores the original state.

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?

A single short sentence with no filler and the verb front-loaded, which is appropriately sized for a no-argument UI command. It is efficient but too terse to be called exemplary.

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 parameters, full annotation coverage, and an output schema present, the definition is close to sufficient for such a simple tool. Still, it omits any mention of the return value or of interaction with other view state, leaving a small but real gap.

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?

The tool takes zero parameters, so there is no parameter meaning for the description to supply; the empty schema is fully self-explanatory. Baseline 4 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?

The description states a specific verb and resource ('Toggles fullscreen mode'), so an agent immediately knows it affects only the display window state. It does not differentiate itself from neighboring view tools such as viewport or reset, which is the only thing keeping it from a 5.

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?

There is no guidance on when to invoke this versus related view commands (viewport, orient, zoom, reset), and no note on whether it is safe to call repeatedly or when a fullscreen state is desirable. Usage is only implied by the tool name.

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