AI agents use browser_cookies_save to create or update resources in Termux Browser Pilot — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Termux Browser Pilot environment.
This tool writes cookie data to persistent storage (JSON file), which is a reversible write operation. While cookies themselves are not highly sensitive in isolation, the ability to export and save them—potentially for exfiltration or replay attacks—combined with the browser automation context elevates severity. An AI agent could misuse this to extract session tokens, authentication credentials, or tracking data.
From the tool's definition Tool name 'browser_cookies_save' and description 'Save browser cookies to a JSON file' indicate creation/modification of persistent data (cookie export to file).
Documented attack patterns abuse exactly the kind of access browser_cookies_save gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Termux Browser Pilot, and nothing reaches the server without passing your rules. This is the rule we recommend for browser_cookies_save:
{
"version": "1",
"default": "deny",
"tools": {
"browser_cookies_save": {
"limits": [
{
"counter": "browser_cookies_save_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}browser_cookies_save 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.
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Save browser cookies to a JSON file. It is categorised as a Write tool in the Termux Browser Pilot MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Termux Browser Pilot MCP server in PolicyLayer and add a rule for browser_cookies_save: 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 Termux Browser Pilot. Nothing to install.
browser_cookies_save 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_cookies_save 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_cookies_save. 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_cookies_save is provided by the Termux Browser Pilot MCP server (salviz/termux-browser-pilot). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Termux Browser Pilot, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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148 Termux Browser Pilot tools catalogued and risk-classified — across an index of 43,000+ MCP servers.