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browser_tabs

Manage browser tabs: list, select, open, or close tabs by index or URL. Returns tab list or active tab snapshot for agent browsing.

Instructions

Manage tabs. action: list (default), select (by index), new (optionally open url), or close (by index). Returns the tab list, or the new active tab's snapshot for select/new.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "browser_tabs"
  }
}

Input Schema

Name	Required	Default
`url`	No
`index`	No
`action`	No	list

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Addedv0.4.0Sep 3, 2026

TDQS

A3.6/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

It discloses the core behaviors: the default action, parameter roles, and return value for select/new actions. However, there are no annotations, and the description does not state what close returns, how side effects like opening a new tab affect the active tab, or error behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded with 'Manage tabs,' then immediately enumerates actions and return behavior. Every sentence carries necessary information, with no filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers actions, parameters, and returns for most cases, but leaves gaps: the close action's return value is not specified, and there is no mention of error handling or prerequisites. An output schema exists, which may cover returns, but the missing close behavior still leaves the description slightly incomplete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, but the description fully compensates by explaining all three parameters: action values (list/select/new/close), index (used by select/close), and url (optional for new). It also clarifies the default action, giving agents complete semantic grounding beyond raw schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly identifies the tool as managing browser tabs and enumerates specific actions (list, select, new, close), making its function concrete. It is distinct from sibling tools like navigate or snapshot, though it does not explicitly name alternatives.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains how each action works and what parameters apply, but gives no guidance on when to use this tool versus sibling tools such as navigate or read. There are no exclusions, preconditions, or routing cues to help an agent choose it over alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.