# 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.

Agent View of the PolicyLayer registry record for `v8_weakrefs_inspect`. HTML page: https://policylayer.com/tools/io-github-vmoranv-jshookmcp/v8-weakrefs-inspect

## Facts

- Tool: `v8_weakrefs_inspect`
- Server: Jshookmcp (`@jshookmcp/jshook`) — https://policylayer.com/tools/io-github-vmoranv-jshookmcp.md
- Install: `npx -y @jshookmcp/jshook`
- Homepage: https://github.com/vmoranv/jshookmcp
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "v8_weakrefs_inspect",
    "arguments": {}
  }
}
```

## Why v8_weakrefs_inspect is rated Low

Tool passively inspects runtime state without modifying data or executing arbitrary operations.

From the tool's own definition: "Enumerate, Inspects, reporting WeakRef and FinalizationRegistry instances"

## Use case

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.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Jshookmcp:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "v8_weakrefs_inspect": {}
  }
}
```

## Other tools on Jshookmcp (735)

- `adb_uninstall` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/adb-uninstall.md
- `cleanup_artifacts` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/cleanup-artifacts.md
- `clear_all_caches` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/clear-all-caches.md
- `clear_collected_data` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/clear-collected-data.md
- `dart_destroy_session` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/dart-destroy-session.md
- `exploit_cache_clear` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/exploit-cache-clear.md
- `exploit_cache_invalidate` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/exploit-cache-invalidate.md
- `extension_uninstall` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/extension-uninstall.md
- `ghidra_decompile` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/ghidra-decompile.md
- `ida_decompile` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/ida-decompile.md
- `jadx_decompile_apk` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/jadx-decompile-apk.md
- `manual_token_cleanup` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/manual-token-cleanup.md
- `memory_antidetection` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/memory-antidetection.md
- `memory_batch_edit` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/memory-batch-edit.md
- `memory_scan_session` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/memory-scan-session.md
- `memory_unregister_type` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/memory-unregister-type.md
- `nemu_destroy_session` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/nemu-destroy-session.md
- `page_cookies` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/page-cookies.md
- `page_local_storage` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/page-local-storage.md
- `page_session_storage` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/page-session-storage.md
- `proxy_clear_logs` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/proxy-clear-logs.md
- `proxy_clear_rules` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/proxy-clear-rules.md
- `proxy_remove_rule` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/proxy-remove-rule.md
- `reset_token_budget` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/reset-token-budget.md
- `session_progress_clear` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/session-progress-clear.md
- `snapshot_restore` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/snapshot-restore.md
- `tls_keylog_seal` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/tls-keylog-seal.md
- `v8_heap_snapshot_delete` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/v8-heap-snapshot-delete.md
- `webhook` — Destructive — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/webhook.md
- `activate_tools` — Execute — https://policylayer.com/tools/io-github-vmoranv-jshookmcp/activate-tools.md
- …and 705 more: https://policylayer.com/tools/io-github-vmoranv-jshookmcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-vmoranv-jshookmcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-vmoranv-jshookmcp