Press a key in the current tab to trigger actions like submitting forms, navigating, or editing text. Returns the updated page snapshot for immediate feedback.
Press a key in the current tab: Enter, Escape, Tab, Backspace, ArrowUp/Down/Left/Right, PageDown, Home, End, or a single character. Returns the new snapshot.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes |
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. It does disclose that the tool returns a new snapshot after pressing the key, which is valuable. However, it does not mention potential side effects such as navigation, form submission, or the requirement that the intended element have focus.
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 short sentences, each earning its place: the first states the action and valid inputs, the second states the return value. The content is front-loaded and contains no filler.
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 single-parameter tool with no output schema and no annotations, the description covers the core requirements: what the tool does, what input values are supported, and what is returned. It could be slightly more complete by noting focus requirements or post-keypress page changes, but the essential information is present.
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 schema only defines 'key' as a string with zero percent description coverage, so the description must compensate. It does so thoroughly by enumerating the valid special keys and clarifying that a single character is also accepted, removing ambiguity about expected input format.
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 uses a specific verb (press), states the resource (current tab), and enumerates the exact set of accepted keys. This clearly distinguishes it from siblings like click (mouse action) and type_text (multi-character text input).
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 key list and 'single character' wording imply this is for discrete key presses, but the description does not explicitly say when to use this tool versus type_text or click, nor does it mention any exclusions or alternatives. Usage context is implied rather than directly stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.