prev_wallpaper

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

Annotations already flag this as non-read-only but non-destructive, so the mutation profile is covered. The description adds that it operates within the current theme rotation, which is useful scope context, but says nothing about wrap-around at the first wallpaper or whether the change is immediate/persistent.

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, front-loaded sentence with the action and scope stated immediately and no wasted words.

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 zero-param, no-output-schema toggle tool with annotations covering its safety profile, the description is nearly sufficient. Only edge behavior (wrap-around, applied immediately) is unstated, a 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?

Zero parameters, so there is nothing for the description to clarify; baseline 4 applies. The 'current theme rotation' phrasing gives a small hint about which selection space is used.

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?

States a specific verb+resource (switch to previous wallpaper) and scopes it to the current theme rotation. The 'previous' qualifier implicitly distinguishes it from next_wallpaper/set_wallpaper/get_wallpaper without naming them, so an agent can still route correctly.

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?

Usage is implied by 'previous' — step backward in the rotation — but there are no explicit when-to-use/when-not conditions and no sibling alternatives (e.g. next_wallpaper) named. Adequate but leaves the agent to infer.

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