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 + localStorage) in a single file. This is the primary way to persist authentication across sessions.

browser_storage_state

Save current state to a JSON file.

→ browser_storage_state
  State saved to: auth-state.json

browser_set_storage_state

Restore a previously saved state.

Parameter	Type	Required	Description
path	string	yes	Path to state JSON file

→ browser_set_storage_state { path: "./auth-state.json" }
→ browser_navigate { url: "https://app.example.com/dashboard" }
→ browser_snapshot
  // Already logged in
  - heading "Dashboard" [level=1]

Workflow: save login, skip it next time

// Login once
→ browser_navigate { url: "https://app.example.com/login" }
→ browser_type { ref: "e3", text: "alice@example.com" }
→ browser_type { ref: "e5", text: "s3cret!" }
→ browser_click { ref: "e7" }
→ browser_snapshot
  - heading "Dashboard" [level=1]

// Save
→ browser_storage_state
  State saved to: auth-state.json

// Next session: restore instead of logging in
→ browser_set_storage_state { path: "./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 by domain
path	string	no	Filter by path

→ browser_cookie_list

  Name          Value       Domain            HttpOnly  Secure  Expires
  session_id    abc123      .example.com      true      true    2024-12-31
  theme         dark        .example.com      false     false   Session
  _ga           GA1.2...    .example.com      false     false   2026-01-01

browser_cookie_get

Parameter	Type	Required	Description
name	string	yes	Cookie name

browser_cookie_set

Parameter	Type	Required	Description
name	string	yes	Cookie name
value	string	yes	Cookie value
domain	string	no	Cookie domain
path	string	no	Cookie path (default: /)
expires	number	no	Expiration as Unix timestamp
httpOnly	boolean	no	HTTP-only flag
secure	boolean	no	Secure flag
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_reload
→ browser_snapshot
  - heading "Sign in" [level=1]
  - textbox "Email" [ref=e3]

localStorage

browser_localstorage_list / get / set / delete / clear

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

→ browser_localstorage_set { key: "onboarding_done", value: "false" }
→ browser_reload
→ browser_snapshot
  // Onboarding wizard appears
  - heading "Welcome! Let's get started" [level=1]

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)