Opens a new browser tab at a specified URL or blank page, optionally in a chosen window or foreground, and returns the new tab ID for automation.
Open a new tab. Returns the new tabId.
| Name | Required | Description | Default |
|---|---|---|---|
| url | No | URL to open; defaults to a blank tab. | |
| windowId | No | Window to open it in; defaults to the frontmost. | |
| timeoutMs | No | How long to wait for the load. | |
| waitUntil | No | How far to wait for loading. | |
| foreground | No | Bring the new tab to the front. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full disclosure burden, and it only adds the return value ('Returns the new tabId'). It does not say whether the new tab steals focus, whether the call blocks until load completes, or how it interacts with existing tabs — meaningful gaps for a browser mutation.
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 with zero filler, and the core action is front-loaded before the return-value note. Nothing could be removed without losing 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?
The schema fully documents all five optional parameters and the description supplies the missing return type, so the mechanics are covered. However, as a mutation-style tool with no annotations, the absence of any context about focus behavior, blocking, or sibling selection leaves it only minimally viable.
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 description coverage is 100%, with every parameter (url, windowId, timeoutMs, waitUntil, foreground) documented inline, so the baseline of 3 applies. The description adds nothing about parameter behavior beyond restating the return value.
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 and resource ('Open a new tab') that an agent can immediately map to intent, and it implicitly separates the tool from browser_new_window and browser_select_tab. It stops short of explicitly differentiating itself from those closely related siblings.
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 browser_new_window, browser_navigate, or browser_select_tab, and no prerequisites or exclusions are given. An agent must infer that this is for creating a tab rather than navigating an existing one.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.