Send mouse scroll events at precise positions, controlling scroll amount and direction for game navigation.
Send mouse scroll wheel event at position
| Name | Required | Description | Default |
|---|---|---|---|
| x | Yes | X position for scroll event | |
| y | Yes | Y position for scroll event | |
| amount | No | Scroll amount (clicks). Default: 1 | |
| direction | No | "up", "down", "left", or "right". Default: "up" |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It does not explain how the scroll event is delivered, whether 'amount' maps to wheel notches, how 'direction' behaves, or what happens when coordinates are invalid. This is a significant gap for a synthetic input 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 concise sentence with no filler. It front-loads the action ('Send') and object ('mouse scroll wheel event') and includes the position qualifier. Given the schema covers details, this length is appropriate.
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 4-parameter tool with no output schema, this description is incomplete. It lacks coordinate system context, interaction with 'amount' and 'direction', boundary behavior, and success/failure semantics. An agent would need to guess or experiment to use it correctly.
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 100%, so the baseline is 3. The description adds only the word 'position', which is redundant with schema parameter names. It doesn't add extra meaning beyond what the schema already documents, but since the schema is complete, the baseline applies.
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 states a specific verb and resource: 'Send mouse scroll wheel event at position'. It clearly identifies the action and target. It doesn't explicitly differentiate from sibling tools, but in context of game_click, game_key_press, game_mouse_move, and game_mouse_drag, its purpose is distinct enough.
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 like game_mouse_drag or game_click. There is no mention of coordinate space, whether it works in the game viewport or OS-level, or any prerequisites. An agent must infer usage from the name and schema.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.