Press a keyboard key (e.g., 'Enter', 'Tab', 'Escape', 'ArrowDown') or a single character. Optional ref focuses an element first — aria-ref token from browser.snapshot ('e7') or a CSS selector.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | ||
| ref | No | ||
| page_id | Yes | ||
| in_workspace | No | Run this one call in this workspace id instead of the session's. Nothing is stored; other sessions are not affected. |
Changes observed during successful MCP inspections.
Input schema / properties / in_workspaceAdded value: +{
+ "description": "Run this one call in this workspace id instead of the session's. Nothing is stored; other sessions are not affected.",
+ "type": "integer"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description usefully explains that ref focuses an element first, but says nothing about error behavior (e.g., unresolvable ref) or side effects of the key press.
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 tight sentences that front-load the core action and then the optional focusing behavior. No filler; each clause adds actionable information.
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 moderate-complexity input tool with no output schema, the description covers the action and the ref mechanism adequately, but omits return/effect details and the workflow relationship to browser_snapshot beyond the token reference.
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?
With only 25% schema coverage, the description compensates well by explaining the two core params: key accepts named keys or a single character, and ref accepts an aria-ref token ('e7') or a CSS selector. page_id and in_workspace are left to schema (in_workspace documented there).
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?
States a specific verb (press) and resource (keyboard key) with concrete examples ('Enter', 'Tab', 'Escape', 'ArrowDown') or a single character. It is clear what the tool does, though it does not explicitly distinguish itself from nearby siblings like browser_type or android_key.
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?
Usage is implied through the reference to 'aria-ref token from browser.snapshot', suggesting a snapshot-then-press workflow, but there is no explicit when-to-use guidance and no stated alternatives (e.g., browser_type for text entry).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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