Auto-Browser

browser.create_session

Create a new browser session with optional start URL, authentication, proxy, and TOTP settings to begin automated browsing.

Instructions

Create a new browser session and optionally navigate to a start URL.

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.create_session"
  }
}

Input Schema

Name	Required	Description
`name`	No	Label shown in session lists.
`start_url`	No	Page to open once the session starts.
`totp_hosts`	No	Hosts where one-time codes from totp_secret may be typed ("*.example.com" also matches subdomains). Defaults to the start_url host.
`user_agent`	No	User-Agent header to send instead of the default.
`totp_secret`	No	Base32 TOTP secret for this session's one-time codes, typed only on totp_hosts.
`auth_profile`	No	Start signed in from a saved auth profile (browser.list_auth_profiles).
`proxy_server`	No	Proxy URL such as http://host:port. Omitted: the deployment default, if any.
`proxy_persona`	No	Named proxy configuration to route through. Not with proxy_server.
`memory_profile`	No	Load a named memory profile into this session.
`proxy_password`	No	Password for proxy_server.
`proxy_username`	No	Username for proxy_server.
`protection_mode`	No	Witness evidence mode; 'confidential' is stricter. Omitted: the deployment default.
`storage_state_path`	No	Playwright storage-state file, relative to the auth directory. Not with auth_profile.

Schema Changelog

Changes observed during successful MCP inspections.

Addedv1.8.1Sep 26, 2026
Removedv1.4.2Jul 25, 2026

Changed13 schema fields changedv1.0.3May 5, 2026

addedInput schema / additionalProperties
```
Added value: +false
```

changedInput schema / properties / auth_profile / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 120,
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / memory_profile

Added value: +{
+  "anyOf": [
+    {
+      "maxLength": 120,
+      "minLength": 1,
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Load a named memory profile into this session.",
+  "title": "Memory Profile"
+}

changedInput schema / properties / name / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 200,
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / protection_mode

Added value: +{
+  "anyOf": [
+    {
+      "enum": [
+        "normal",
+        "confidential"
+      ],
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Protection Mode"
+}

changedInput schema / properties / proxy_password / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 500,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / proxy_persona

Added value: +{
+  "anyOf": [
+    {
+      "maxLength": 200,
+      "minLength": 1,
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "title": "Proxy Persona"
+}

changedInput schema / properties / proxy_server / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 500,
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

changedInput schema / properties / proxy_username / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 200,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

changedInput schema / properties / start_url / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 2000,
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

changedInput schema / properties / storage_state_path / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 500,
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

changedInput schema / properties / totp_secret / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 500,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

changedInput schema / properties / user_agent / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 2000,
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

First observedv0.5.0Mar 26, 2026

TDQS

A3.5/5.0

Behavior3/5

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

Annotations already indicate this is a non-read-only, non-idempotent, non-destructive operation, so the description doesn't need to restate that. The description adds the 'optionally navigate' behavior, which is useful. However, it doesn't disclose side effects like session limits, resource cleanup, or whether creating a session with the same name replaces or errors, which would add value 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.

Conciseness5/5

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

The description is a single, front-loaded sentence that states the core action and the optional behavior. Every word earns its place; there is no fluff or repetition of schema details.

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?

For a 13-parameter creation tool with no output schema, the description is minimal but the schema is rich and fully covers parameters. The main missing context is what the tool returns (e.g., session ID) and how it relates to fork_session, which an agent would need to know to use it correctly. The annotations cover safety, so the description doesn't need to repeat that.

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

Parameters3/5

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

Schema description coverage is 100%, so the schema already documents all 13 parameters. The description adds no parameter-level meaning beyond the schema. Baseline 3 is appropriate because the schema carries the full burden and the description doesn't need to compensate.

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 clear verb and resource: 'Create a new browser session and optionally navigate to a start URL.' This distinguishes it from session-listing, closing, and observation siblings. However, it doesn't explicitly contrast with fork_session, which also creates a session, so it falls short of full sibling differentiation.

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 the primary use case (starting a new session) and the optional start URL, but it does not state when to prefer this over fork_session or when not to use it. The schema hints at exclusions (e.g., proxy_persona not with proxy_server, storage_state_path not with auth_profile), but the description itself provides no usage guidance.

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