is_dark_mode

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

With no annotations provided, the description must disclose behavior itself. 'Check if dark mode is currently enabled' clearly indicates a read-only operation with no side effects. It doesn't detail output format or edge cases, but for a no-parameter system query, this is sufficient.

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 a single, front-loaded sentence with no redundant words. Every word contributes to conveying the tool's function, achieving maximum conciseness.

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?

Given the tool's simplicity (no parameters, no nested objects), the description fully captures what it does. An output schema exists to specify the return type, so the description needn't elaborate further.

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 accepts zero parameters, making parameter semantics trivially clear. The input schema is an empty object, and no parameter-specific explanation is needed. The baseline for zero parameters is 4.

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 'Check' and identifies the resource 'dark mode' with an explicit condition 'currently enabled'. It clearly distinguishes itself from sibling tools like toggle_dark_mode or set_dark_mode, making its purpose unambiguous.

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 verb 'Check' clearly implies this tool is for querying the current state, not modifying it. It lacks explicit references to alternative tools or 'when-not-to-use' guidance, so it doesn't reach a perfect 5, but the usage context is very clear.

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