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browser_session

Manage isolated browser sessions with unique cookies and optional live-view streaming. Supports current, list, close, close_all, and stream actions.

Instructions

Purpose: Manage isolated stealth browser identities and the optional loopback-only live-view stream. Each session has its own cookies… Constraints: action selects current, list, close, close_all, or stream. Stream discovers the selected session's loopback WebSocket and safely relays it to the configured host port.… Example: browser_session(action='list')

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "action": "<action>"
    },
    "name": "browser_session"
  }
}

Input Schema

Name	Required	Description	Default
`action`	Yes
`session`	No
`stream_port`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 8, 2026

TDQS

B3.2/5.0

Behavior3/5

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

With no annotations provided, the description carries the full burden. It discloses key behaviors: sessions are isolated, each has its own cookies, and the stream action relays a loopback WebSocket to a configured host port. However, it does not mention side effects of close/close_all (e.g., whether cookies are discarded) or any other consequences, leaving behavioral transparency partial.

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

Conciseness4/5

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

The description is well-structured with Purpose, Constraints, and Example sections, and it front-loads the core purpose. It is concise, though the use of ellipses suggests truncation, slightly reducing clarity. Overall, it is appropriately sized and organized.

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 the main functions and constraints, and an output schema exists so return values are not necessary. However, it leaves gaps in parameter semantics (session) and side-effect disclosure, making it adequate but not fully complete for a tool with multiple actions and no annotations.

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

Parameters2/5

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

Schema description coverage is 0%, so the description must explain parameters. It explains the 'action' enum values and hints at 'stream_port' via 'configured host port', but the 'session' parameter is not described at all. The phrase 'selected session' implies how to select, but the parameter itself remains ambiguous, leaving one of three params unexplained.

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 states a specific resource ('isolated stealth browser identities' and 'loopback-only live-view stream') and enumerates the primary actions (current, list, close, close_all, stream). The verb 'Manage' is slightly generic, but the resource is well-defined and clearly distinguishes this session management tool from sibling browser interaction tools.

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

Usage Guidelines3/5

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

The description implies usage for managing browser sessions, but does not explicitly state when to use this tool vs alternatives, nor provide exclusions. The constraints section lists allowed actions, giving some guidance, but no direct comparison to sibling tools like browser_open or system_start_new_session is offered.

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