set_opacity

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

The description fully discloses key behaviors: live update ('Live update on the window'), persistence ('persist to appearance.opacity'), and input validation ('Values outside [0.1, 1.0] are rejected'). With no annotations present, this provides complete clarity.

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 sentences, no extraneous words. The first sentence states the action and range. The second adds key behavioral details. Every sentence earns its place.

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 input, behavior, and validation sufficiently for invocation. However, it does not mention the return type (e.g., success/failure), which could be helpful for debugging. Given the tool's simplicity, minor 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 single parameter 'value' has schema coverage of 100% but the description enriches it with contextual meaning: the range explained in plain language ('0.1 = mostly transparent, 1.0 = fully opaque'), relation to settings, and rejection policy. This adds significant value beyond the schema.

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 ('Set'), the target ('Windy Word window opacity'), and the valid range (0.1-1.0). It also references the settings path ('Mirrors Settings → Appearance → Window Opacity'), which adds specificity and distinguishes it from other window-related tools.

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 use for adjusting window transparency and references the settings location, providing context. However, it does not explicitly state when to use versus alternatives (though no direct alternative exists among siblings).

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