Probe browser runtime capabilities and compare them with Node rebuild assumptions.
AI agents call probe_runtime_capabilities to retrieve information from JS Reverse MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool reads and queries runtime environment properties to analyze browser capabilities versus Node.js assumptions. It performs passive reconnaissance of the runtime environment without executing arbitrary code, modifying state, or triggering side effects. The severity is low because incorrect probing results would only provide inaccurate diagnostic information, not cause harm.
From the tool's definition Tool name 'probe_runtime_capabilities' and description 'Probe browser runtime capabilities and compare them with Node rebuild assumptions' indicate information retrieval and comparison operations.
Attacks that exploit this kind of access
Probe browser runtime capabilities and compare them with Node rebuild assumptions. It is categorised as a Read tool in the JS Reverse MCP MCP Server, which means it retrieves data without modifying state.
Register the JS Reverse MCP server in PolicyLayer and add a rule for probe_runtime_capabilities: 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 JS Reverse MCP. Nothing to install.
probe_runtime_capabilities 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 probe_runtime_capabilities 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 probe_runtime_capabilities. 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.
probe_runtime_capabilities is provided by the JS Reverse MCP server (noone-hub/jsreverser-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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