list_displays

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

With no annotations provided, the description carries full burden but offers minimal behavioral insight. It mentions the output includes 'bounds and pixel sizes', which hints at return format, but doesn't disclose whether this is a read-only operation, potential side effects, or performance characteristics. For a tool with zero annotation coverage, this is inadequate.

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, efficient sentence that front-loads the core action ('List available displays') and adds specific detail ('with bounds and pixel sizes'). There is zero wasted verbiage, making it highly concise and well-structured for quick comprehension.

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 output schema), the description is minimally adequate. It states what the tool does and hints at output content, but lacks guidance on usage versus siblings and behavioral details. For a zero-parameter tool, this is acceptable but not comprehensive.

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 has zero parameters, and schema description coverage is 100% (though trivial). The description doesn't need to compensate for missing parameter documentation. A baseline of 4 is appropriate as there are no parameters to explain beyond what the empty schema already indicates.

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 verb ('List') and resource ('available displays'), specifying what information is included ('with bounds and pixel sizes'). It distinguishes from siblings like 'list_windows' by focusing on displays rather than windows. However, it doesn't explicitly contrast with 'screenshot_display' which also operates on displays.

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?

No guidance is provided on when to use this tool versus alternatives. The description doesn't mention when to choose 'list_displays' over 'list_windows' or 'screenshot_display', nor does it specify prerequisites or context for usage. The agent must infer usage from tool names alone.

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