Press keyboard keys or key combinations on the active web page to trigger actions, navigate, or fill forms during browser automation.
Press a keyboard key (or combination) on the current page.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | Key to press, e.g. 'Enter', 'ArrowDown', 'a', or a combination like 'Control+A'. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It only states the action without revealing side effects (e.g., whether it triggers keyboard events, requires page focus, or works on any element). The agent gets no information about prerequisites or outcomes.
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, front-loading the core action. It is appropriately sized for the tool's simplicity.
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 simple tool with one parameter and no output schema, the description is minimally adequate, but it lacks usage context and behavioral transparency. It does not tell the agent when to prefer this over browser_type, nor does it disclose any side effects, leaving gaps in decision-making.
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 input schema fully describes the 'key' parameter with examples, so the description adds no additional meaning beyond what the schema already provides. Baseline score of 3 is appropriate since schema coverage is 100%.
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 ('press') and resource ('keyboard key') on the current page, and explicitly mentions combinations like 'Control+A', making it distinct from siblings such as browser_click and browser_type. It clearly conveys what the tool does.
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 explicit guidance on when to use this tool versus alternatives like browser_type. The implication is that it is for key presses rather than typing text, but there is no mention of exclusions or when it should not be used (e.g., for text input or dialog handling).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.