Storage & Authentication

Manage cookies, localStorage, sessionStorage, and save/restore full browser state for authentication persistence. Requires the storage capability.

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": ["@playwright/mcp@latest", "--caps=storage"]
    }
  }
}

Storage state

Save and restore the full browser state (cookies + local storage) in a single file. This is the primary way to persist authentication across sessions.

browser_storage_state

Save the current state to a JSON file.

Parameter	Type	Required	Description
filename	string	no	File to save to. Relative names resolve against the workspace root. Defaults to storage-state-{timestamp}.json in the output directory

→ browser_storage_state { filename: "auth-state.json" }
  - [Storage state](auth-state.json)

browser_set_storage_state

Restore a previously saved state. Existing cookies and local storage are cleared first.

Parameter	Type	Required	Description
filename	string	yes	Path to the storage state file. Relative names resolve against the workspace root

→ browser_set_storage_state { filename: "auth-state.json" }
  Storage state restored from auth-state.json

→ browser_navigate { url: "https://app.example.com/dashboard" }
  // Already logged in
  - heading "Dashboard" [level=1] [ref=e2]

Workflow: save login, skip it next time

// Login once
→ browser_navigate { url: "https://app.example.com/login" }
→ browser_type { target: "e3", text: "alice@example.com" }
→ browser_type { target: "e5", text: "s3cret!" }
→ browser_click { target: "e7" }

  - heading "Dashboard" [level=1] [ref=e2]

// Save
→ browser_storage_state { filename: "auth-state.json" }

// Next session: restore instead of logging in
→ browser_set_storage_state { filename: "auth-state.json" }
→ browser_navigate { url: "https://app.example.com/dashboard" }

Or load state automatically on server startup:

["@playwright/mcp@latest", "--caps=storage", "--isolated", "--storage-state=./auth-state.json"]

Cookies

browser_cookie_list

Parameter	Type	Required	Description
domain	string	no	Filter cookies by domain
path	string	no	Filter cookies by path

→ browser_cookie_list

  session_id=abc123 (domain: .example.com, path: /)
  theme=dark (domain: .example.com, path: /)

browser_cookie_get

Parameter	Type	Required	Description
name	string	yes	Cookie name to get

→ browser_cookie_get { name: "session_id" }

  session_id=abc123 (domain: .example.com, path: /, httpOnly: true, secure: true, sameSite: Lax)

browser_cookie_set

Domain defaults to the current page's hostname and path defaults to /.

Parameter	Type	Required	Description
name	string	yes	Cookie name
value	string	yes	Cookie value
domain	string	no	Cookie domain
path	string	no	Cookie path
expires	number	no	Expiration as a Unix timestamp
httpOnly	boolean	no	Whether the cookie is HTTP only
secure	boolean	no	Whether the cookie is secure
sameSite	string	no	Strict, Lax, or None

browser_cookie_delete / browser_cookie_clear

Delete a specific cookie by name, or clear all cookies.

Workflow: test logout by clearing cookies

→ browser_cookie_clear
→ browser_navigate { url: "https://app.example.com/dashboard" }

  - heading "Sign in" [level=1] [ref=e2]
  - textbox "Email" [ref=e3]

localStorage

Manage localStorage key-value pairs for the current origin.

Tool	Parameters
browser_localstorage_list	(none)
browser_localstorage_get	key (string)
browser_localstorage_set	key (string), value (string)
browser_localstorage_delete	key (string)
browser_localstorage_clear	(none)

→ browser_localstorage_list

  user_preferences={"theme":"dark","lang":"en"}
  onboarding_done=true

→ browser_localstorage_set { key: "onboarding_done", value: "false" }
→ browser_navigate { url: "https://app.example.com" }

  // Onboarding wizard appears
  - heading "Welcome! Let's get started" [level=1] [ref=e2]

sessionStorage

Same interface as localStorage but session-scoped — data is cleared when the tab closes.

Tool	Parameters
browser_sessionstorage_list	(none)
browser_sessionstorage_get	key (string)
browser_sessionstorage_set	key (string), value (string)
browser_sessionstorage_delete	key (string)
browser_sessionstorage_clear	(none)