v8_allocation_track
Track live V8 allocations via CDP HeapProfiler object tracking. Enables the HeapProfiler, calls startTrackingHeapObjects({ trackAllocations: true }) to collect lastSeenObjectId events for a capture window (default 3s), then stopTrackingHeapObjects (with an explicit takeHeapSnapshot fallback) to r...
This record as markdown: /tools/io-github-vmoranv-jshookmcp/v8-allocation-track.md
What v8_allocation_track does on Jshookmcp
AI agents call v8_allocation_track 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_allocation_track is rated Low
Collects memory allocation data without modifying state; requires CDP context and reads heap information.
From the tool's definition Track live V8 allocations, HeapProfiler, startTrackingHeapObjects, takeHeapSnapshot
Attacks that exploit this kind of access
The rule that runs v8_allocation_track 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_allocation_track, this is the rule to start with:
v8_allocation_track 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_allocation_track call is checked against it from then on.
Questions about v8_allocation_track
Track live V8 allocations via CDP HeapProfiler object tracking. Enables the HeapProfiler, calls startTrackingHeapObjects({ trackAllocations: true }) to collect lastSeenObjectId events for a capture window (default 3s), then stopTrackingHeapObjects (with an explicit takeHeapSnapshot fallback) to return currently-live objects seen during the window with their allocation stack (top frame + size). Useful for finding objects that survive GC during a specific interaction. Requires browser/page CDP context and V8 natives for full stack resolution. 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_allocation_track: 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_allocation_track 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_allocation_track 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_allocation_track. 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_allocation_track 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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