Save the current browser session (cookies, localStorage, URL, headers) to a file for later restoration. Useful for preserving login state across conversation restarts.
AI agents use browser_save_session to create or update resources in Playwright Autopilot — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Playwright Autopilot environment.
This tool writes session data (cookies, localStorage, headers) to a file. While the write itself is reversible and not destructive, it stores sensitive authentication tokens and session identifiers that could be misused if written to unintended locations or with insufficient access controls.
From the tool's definition Tool description states it 'Save[s] the current browser session (cookies, localStorage, URL, headers) to a file' — this is a create/write operation that persists data to disk.
Documented attack patterns abuse exactly the kind of access browser_save_session gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Playwright Autopilot, and nothing reaches the server without passing your rules. This is the rule we recommend for browser_save_session:
{
"version": "1",
"default": "deny",
"tools": {
"browser_save_session": {
"limits": [
{
"counter": "browser_save_session_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}browser_save_session stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Save the current browser session (cookies, localStorage, URL, headers) to a file for later restoration. Useful for preserving login state across conversation restarts. It is categorised as a Write tool in the Playwright Autopilot MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Playwright Autopilot MCP server in PolicyLayer and add a rule for browser_save_session: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Playwright Autopilot. Nothing to install.
browser_save_session is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the browser_save_session rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for browser_save_session. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
browser_save_session is provided by the Playwright Autopilot MCP server (kaizen-yutani/playwright-autopilot). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Playwright Autopilot, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
51 Playwright Autopilot tools catalogued and risk-classified — across an index of 43,000+ MCP servers.