v8_weakrefs_inspect
Enumerate WeakRef and FinalizationRegistry instances in the page via Runtime.evaluate. Inspects registered finalization callbacks and live WeakRef targets, reporting how many WeakRefs are dereferenced vs cleared and which FinalizationRegistry callbacks have pending entries. Useful for diagnosing ...
This record as markdown: /tools/io-github-vmoranv-jshookmcp/v8-weakrefs-inspect.md
What v8_weakrefs_inspect does on Jshookmcp
AI agents call v8_weakrefs_inspect to retrieve information from Jshookmcp without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why v8_weakrefs_inspect is rated Low
Tool passively inspects runtime state without modifying data or executing arbitrary operations.
From the tool's definition Enumerate, Inspects, reporting WeakRef and FinalizationRegistry instances
Attacks that exploit this kind of access
The rule that runs v8_weakrefs_inspect safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Jshookmcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For v8_weakrefs_inspect, this is the rule to start with:
v8_weakrefs_inspect is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Jshookmcp, apply this rule, and every v8_weakrefs_inspect call is checked against it from then on.
Questions about v8_weakrefs_inspect
Enumerate WeakRef and FinalizationRegistry instances in the page via Runtime.evaluate. Inspects registered finalization callbacks and live WeakRef targets, reporting how many WeakRefs are dereferenced vs cleared and which FinalizationRegistry callbacks have pending entries. Useful for diagnosing cleanup logic in long-lived pages. Requires browser/page CDP context. It is categorised as a Read tool in the Jshookmcp MCP Server, which means it retrieves data without modifying state.
Register the Jshook MCP server in PolicyLayer and add a rule for v8_weakrefs_inspect: 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 Jshookmcp. Nothing to install.
v8_weakrefs_inspect 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 v8_weakrefs_inspect 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 v8_weakrefs_inspect. 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.
v8_weakrefs_inspect is provided by the Jshook MCP server (@jshookmcp/jshook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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