test_dark_mode

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

The description discloses that the tool toggles the color scheme and takes a screenshot, which are the main behaviors. However, it does not mention side effects (e.g., session persistence), reversibility, or whether the screenshot is returned or stored. No annotations are provided to fill these gaps.

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?

Two short sentences immediately convey the action and result. Every word is necessary, with no 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?

The description covers the core functionality: toggling and screenshotting. While no output schema exists, the mention of a screenshot implies the output includes that screenshot. However, it could be clearer about the return type (e.g., whether the screenshot data is returned directly). Overall, it is sufficient for a tool with simple behavior.

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 input schema already fully describes both parameters with 100% coverage. The description adds context that 'mode' toggles the scheme and that a screenshot is taken, but does not provide additional semantic value beyond the schema's 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 uses a specific verb 'Toggle' and identifies the resource 'prefers-color-scheme on a session,' making the purpose clear. It distinguishes this tool from siblings like 'get_screenshot' or 'set_viewport' by combining toggling and screenshotting.

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 tool is used for testing dark mode appearance, but does not explicitly state when to use this tool versus alternatives like combining 'set_viewport' and 'get_screenshot.' No exclusions or prerequisites are mentioned.

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