left_mouse_up

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

With no annotations provided, the description must carry the full behavioral burden. It only states the core action and does not disclose prerequisites (e.g., a prior press), side effects, or any state changes beyond the release. This is a significant gap for a mutation-like tool.

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 sentence with no filler words, which is appropriately concise. The action is front-loaded. However, its brevity borders on under-specification, though that is more an issue of completeness than 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 has a nested object parameter and no annotations or output schema, the description is insufficiently complete. It does not explain the meaning of 'target', any preconditions, or how it interacts with other tools like left_mouse_down. An agent would struggle to call it correctly without additional context.

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 description coverage is 0%, and the description provides no explanation of the 'target' parameter or its nested properties (type, index, state_id). The agent has to infer what 'target' refers to, which is a major omission for a required parameter. The description adds no semantic value beyond the schema's bare structure.

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: releasing a previously pressed left mouse button. This distinguishes it from siblings like left_mouse_down (press) and left_click (press and release), making the purpose unambiguous and 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?

There is no explicit guidance on when to use this tool versus alternatives. The phrase 'previously pressed' implies a prior state, but it does not explicitly instruct to use it after left_mouse_down, nor does it mention when not to use it (e.g., for a single click). The usage context is left to inference.

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