set_wallpaper

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

With no annotations, the description carries the full burden. It discloses that the image loads on demand and no preloading is needed, which is valuable behavioral context. However, it lacks details on error handling or permissions.

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, both essential. The first defines the core functionality and fallback, the second adds a useful behavioral note. 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?

For a setter tool with no output schema and no annotations, the description covers core behavior, parameter nuances, and a behavioral note. Missing details on error states or return values, but adequate for typical usage.

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?

Schema coverage is 100%, but the description adds extra meaning: for monitor, it explains the fallback behavior; for fit_mode, it notes version-dependent supported values and the default behavior upon omission.

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 tool sets wallpaper for a specific monitor or as a fallback, distinguishing it from read-only tools like list_active_wallpapers. The verb 'set' and resource 'wallpaper' are specific.

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 explains when to use the monitor parameter (to set for a specific monitor) vs omitting it (to set fallback). However, it does not explicitly mention alternative tools or when not to use this tool.

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