browser_keyPress a key or key combination on a page to submit forms, close dialogs, move through lists, or trigger shortcuts; returns what changed on screen.
Press a key or combination in the page: submit, close a dialog, move through a list, a shortcut. Text into a field: browser_type. Answers with what changed on screen.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | Key or keys joined with +, e.g. Enter, Escape, shift+Tab, ctrl+a |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false and openWorldHint=true, so the description does not need to establish that this is a mutating action. It usefully adds that the tool 'answers with what changed on screen', which tells the agent to expect a post-action observation, though it could say more about side effects like form submission or navigation.
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 two compact sentences with no wasted text. Usage examples and the browser_type alternative are front-loaded, making it easy to scan.
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 one-parameter browser action with annotations covering safety and openness, the description supplies enough context: what it does, when to use it, the typing alternative, and the kind of response to expect. No output schema exists, but the description states 'answers with what changed on screen', which is sufficient.
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 100%, and the schema already explains that the key parameter accepts keys joined with '+', including examples. The description reinforces the combination concept but adds no syntax or format detail beyond the schema, so the baseline 3 is appropriate.
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 and resource: pressing a key or key combination in the page. It also distinguishes the tool from browser_type by explicitly assigning text entry to that sibling, so an agent can select correctly without opening both schemas.
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?
Gives concrete when-to-use examples (submit, close a dialog, move through a list, shortcut) and explicitly names the alternative for typing text: browser_type. This is clear routing guidance with an explicit exclusion.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.