browser_keyboard_pressPress keyboard keys or key chords in a browser session to simulate user input for parallel browser automation.
Press a keyboard key or key chord.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | Playwright key name, e.g. "Enter", "ArrowDown", "Control+A". | |
| sessionId | Yes |
Changes observed during successful MCP inspections.
v0.1.14Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It only states the action without disclosing any behavioral traits such as whether it waits for page load, requires focus, triggers events, or affects page state. For a mutation-like action, this is a significant gap.
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 waste, efficiently stating the core purpose. It is well-structured in terms of length, though it could be expanded without losing 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's simplicity, one might argue a short description suffices, but it lacks essential context: no mention of when to use it vs. typing, no behavioral expectations, and no indication of return values or side effects. For an agent to correctly select and invoke this tool, more detail is needed.
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 coverage is only 50%, with the 'key' parameter described in the schema but 'sessionId' undocumented. The description adds no parameter detail beyond the schema, failing to compensate for the missing sessionId semantics. The example in the schema is helpful, but the description does not reinforce it.
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 a specific verb ('Press') and resource ('keyboard key or key chord'), which is unambiguous and distinguishes it from typing tools. However, it does not explicitly name a sibling like browser_keyboard_type, so differentiation relies on the reader inferring that 'press' is for single keys/shortcuts.
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 guidance on when to use this tool versus alternatives such as browser_keyboard_type (for typing strings) or mouse-based tools. The description does not mention any exclusions or context, leaving the agent to guess the appropriate use case.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.