# extract_variables

Identify and weight the key variables driving an entity

Agent View of the PolicyLayer registry record for `extract_variables`. HTML page: https://policylayer.com/tools/io-github-homenshum-nodebench/extract-variables

## Facts

- Tool: `extract_variables`
- Server: Nodebench (`nodebench-mcp`) — https://policylayer.com/tools/io-github-homenshum-nodebench.md
- Install: `npx -y nodebench-mcp`
- Homepage: https://github.com/HomenShum/nodebench-ai
- 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": "extract_variables",
    "arguments": {}
  }
}
```

## Why extract_variables is rated Low

The tool performs data analysis and extraction of variables from an entity without modifying, deleting, or executing arbitrary operations. It returns insights derived from existing data, making it a Read operation. The narrow, analytical scope and lack of side effects justify low severity.

From the tool's own definition: "Tool description states 'Identify and weight the key variables' — this is an analysis and identification task with no mutations to data. The verb 'extract' combined with 'identify' indicates retrieval and analysis of information from existing data."

## Use case

AI agents call extract_variables to retrieve information from Nodebench 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 Nodebench:

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

## Other tools on Nodebench (823)

- `abandon_cycle` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/abandon-cycle.md
- `archiveDocument` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/archivedocument.md
- `cleanup_stale_runs` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/cleanup-stale-runs.md
- `deeptrace_revoke_passport` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/deeptrace-revoke-passport.md
- `delete_learning` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/delete-learning.md
- `delete_sandbox_policy` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/delete-sandbox-policy.md
- `deleteAgentMemory` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/deleteagentmemory.md
- `removeDocumentFromFolder` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/removedocumentfromfolder.md
- `share_revoke_packet_link` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/share-revoke-packet-link.md
- `unload_toolset` — Destructive — https://policylayer.com/tools/io-github-homenshum-nodebench/unload-toolset.md
- `benchmark_models` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/benchmark-models.md
- `bootstrap_parallel_agents` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/bootstrap-parallel-agents.md
- `build_banking_packet` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/build-banking-packet.md
- `build_company_profile_starter` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/build-company-profile-starter.md
- `build_founder_operating_model` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/build-founder-operating-model.md
- `build_research_digest` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/build-research-digest.md
- `build_shared_context_subscription` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/build-shared-context-subscription.md
- `build_shared_context_subscription_manifest` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/build-shared-context-subscription-manifest.md
- `build_submission_export` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/build-submission-export.md
- `build_temporal_graph` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/build-temporal-graph.md
- `burst_capture` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/burst-capture.md
- `call_driver_tool` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/call-driver-tool.md
- `call_llm` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/call-llm.md
- `call_openclaw_skill` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/call-openclaw-skill.md
- `call_webmcp_tool` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/call-webmcp-tool.md
- `capture_surface_stats` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/capture-surface-stats.md
- `capture_ui_screenshot` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/capture-ui-screenshot.md
- `compile_decision_packet` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/compile-decision-packet.md
- `compile_scenarios` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/compile-scenarios.md
- `compile_tension_model` — Execute — https://policylayer.com/tools/io-github-homenshum-nodebench/compile-tension-model.md
- …and 793 more: https://policylayer.com/tools/io-github-homenshum-nodebench.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-homenshum-nodebench · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-homenshum-nodebench