AI agents use sessionstorage_set to create or update resources in MCP Camoufox — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP Camoufox environment.
This tool creates or modifies browser sessionStorage, which is reversible client-side storage. It qualifies as Write rather than Execute because it does not run arbitrary code or trigger external operations—it simply sets a key-value pair.
From the tool's definition Tool name 'sessionstorage_set' and description 'Set a sessionStorage item' indicate creating or modifying sessionStorage data in a browser context.
Documented attack patterns abuse exactly the kind of access sessionstorage_set gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Camoufox, and nothing reaches the server without passing your rules. This is the rule we recommend for sessionstorage_set:
{
"version": "1",
"default": "deny",
"tools": {
"sessionstorage_set": {
"limits": [
{
"counter": "sessionstorage_set_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}sessionstorage_set 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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Set a sessionStorage item. It is categorised as a Write tool in the MCP Camoufox MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP Camoufox MCP server in PolicyLayer and add a rule for sessionstorage_set: 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 MCP Camoufox. Nothing to install.
sessionstorage_set 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 sessionstorage_set 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 sessionstorage_set. 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.
sessionstorage_set is provided by the MCP Camoufox MCP server (robithyusuf/mcp-camoufox). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Camoufox, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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102 MCP Camoufox tools catalogued and risk-classified — across an index of 43,000+ MCP servers.