List all saved browser sessions.
AI agents call web_list_sessions to retrieve information from Fourth Playwright MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only operation that queries and returns information about existing browser sessions. It has no side effects, does not modify data, does not execute code or commands, and does not delete or destroy anything. It is a straightforward data retrieval operation, classifying it as Read category with low severity since listing session metadata poses minimal risk even if misused by an AI agent.
From the tool's definition Tool name 'web_list_sessions' and description 'List all saved browser sessions' indicate retrieval/querying of existing session data with no modification, deletion, or execution of code.
Attacks that exploit this kind of access
List all saved browser sessions. It is categorised as a Read tool in the Fourth Playwright MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Fourth Playwright MCP Server MCP server in PolicyLayer and add a rule for web_list_sessions: 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 Fourth Playwright MCP Server. Nothing to install.
web_list_sessions is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the web_list_sessions 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 web_list_sessions. 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.
web_list_sessions is provided by the Fourth Playwright MCP Server MCP server (rev4nchist/fourth-playwright-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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