v8_turbofan_graph
Collect and visualize V8 TurboFan IR (sea-of-nodes / Turboshaft graph). Two modes: (1) Provide JS source code — spawns an isolated V8 child with --trace-turbo to generate IR JSON, then parses nodes, edges, phases, and opcode histogram. (2) Provide a traceDir path to read already-generated turbo-*...
This record as markdown: /tools/io-github-vmoranv-jshookmcp/v8-turbofan-graph.md
What v8_turbofan_graph does on Jshookmcp
AI agents invoke v8_turbofan_graph to trigger actions in Jshookmcp. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why v8_turbofan_graph is rated High
Tool executes arbitrary JavaScript source code in a V8 child process.
From the tool's definition spawns an isolated V8 child with --trace-turbo to generate IR JSON
Attacks that exploit this kind of access
The rule that runs v8_turbofan_graph 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_turbofan_graph, this is the rule to start with:
v8_turbofan_graph stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. 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_turbofan_graph call is checked against it from then on.
Questions about v8_turbofan_graph
Collect and visualize V8 TurboFan IR (sea-of-nodes / Turboshaft graph). Two modes: (1) Provide JS source code — spawns an isolated V8 child with --trace-turbo to generate IR JSON, then parses nodes, edges, phases, and opcode histogram. (2) Provide a traceDir path to read already-generated turbo-*.json files (e.g. from a browser launched with --trace-turbo). Returns per-function graph summaries with phase-level node/edge counts, sample nodes, and opcode distribution. It is categorised as a Execute tool in the Jshookmcp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Jshook MCP server in PolicyLayer and add a rule for v8_turbofan_graph: 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_turbofan_graph is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the v8_turbofan_graph 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_turbofan_graph. 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_turbofan_graph 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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