Manage tabs in a Playwright session: list open tabs, open a new one, close the current or indexed tab, or select a tab by index to control the active page.
List, create, close, or select a browser tab.
| Name | Required | Description | Default |
|---|---|---|---|
| index | No | Tab index, used for close/select. If omitted for close, current tab is closed. | |
| action | Yes | Operation to perform | |
| sessionId | No | Target session ID. Omit to use the active session. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare destructiveHint=true and openWorldHint=true, so the agent knows this can destroy state. The description does not disclose what 'close' destroys, whether 'select' affects focus, or any side effects. It merely restates the operations listed in the enum, adding no behavioral context beyond the annotations.
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?
Extremely concise single sentence that front-loads all operations. No waste.
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 annotations cover safety profile and the schema covers parameters, the description is minimally adequate. However, for a tool with multiple operations and destructive potential, the description could explain return values (e.g., list returns tab info) and the effect of each action, which is missing.
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%, so the schema fully documents parameters (index, action, sessionId). The description adds nothing beyond what the schema provides; 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 set of verbs (list, create, close, select) on a clear resource (browser tab). It's distinguishable from siblings like browser_navigate, though it doesn't explicitly contrast with them.
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?
No guidance on when to use this versus alternatives like browser_navigate (which could also open tabs). No mention of prerequisites or conditions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.