# tengu_v3_reference_lookup

REVERSE IDENTIFIER LOOKUP — give it a CUSIP, ISIN, SEDOL, ticker, estimate-vendor ticker, gvkey, regulator filer number, entity id or private-company-graph id and it returns the security (or, for an ISSUER key, every security under that issuer) plus which rung matched and whether that binding is still current. Exactly one identifier per call. RETIRED identifiers resolve by default — 759,618 of the 969,333 bindings on file are retired, which is precisely why a stale identifier in your own data still lands, and it comes back with the date it was replaced and by what. Issuer keys NEVER nominate one security: an issuer can carry a common line, other share classes and a foreign listing, so all of them are returned and the grain is stated. Use it to turn a CUSIP-keyed custodian file into tickers, to find the ticker behind a regulator filing, or to audit whether an identifier in your own data has gone stale. Rung coverage, measured 2026-08-02: CUSIP9 and CUSIP8 100% of 77,313 securities, ISIN 79.4%, SEDOL 74.2%, regulator filer number 67.8%, estimate-vendor ticker 37.2%.

Agent View of the PolicyLayer registry record for `tengu_v3_reference_lookup`. HTML page: https://policylayer.com/tools/tengu-mcp/tengu-v3-reference-lookup

## Facts

- Tool: `tengu_v3_reference_lookup`
- Server: Tengu (`Hlobo-dev/tengu-mcp`) — https://policylayer.com/tools/tengu-mcp.md
- Homepage: https://github.com/Hlobo-dev/tengu-mcp
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server rate-limited: no
- Parameters: 10
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `cik` | string | no |  |
| `isin` | string | no |  |
| `cusip` | string | no |  |
| `gvkey` | string | no |  |
| `ibtic` | string | no |  |
| `sedol` | string | no |  |
| `ticker` | string | no |  |
| `entity_id` | string | no |  |
| `include_retired` | boolean | no |  |
| `private_company_id` | string | no |  |

Parameters from the server's own tool schema.

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

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "tengu_v3_reference_lookup",
    "arguments": {}
  }
}
```

## Why tengu_v3_reference_lookup is rated Low

Even though tengu_v3_reference_lookup only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.

Risk signals: High parameter count (10 properties) · Bulk/mass operation — affects multiple targets

## Use case

AI agents call tengu_v3_reference_lookup to retrieve information from Tengu 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 Tengu:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "tengu_v3_reference_lookup": {}
  }
}
```

## Other tools on Tengu (336)

- `tengu_v3_features_dataset` — Destructive — https://policylayer.com/tools/tengu-mcp/tengu-v3-features-dataset.md
- `tengu_v3_intel_borrow_cost_history` — Destructive — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-borrow-cost-history.md
- `tengu_v3_intel_insider_flow` — Destructive — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-insider-flow.md
- `tengu_v3_intel_risk_free_rate` — Destructive — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-risk-free-rate.md
- `tengu_v3_intel_sec13f_changes` — Destructive — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-sec13f-changes.md
- `tengu_v3_backtest_run_detail` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-backtest-run-detail.md
- `tengu_v3_briefing_daily` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-briefing-daily.md
- `tengu_v3_factor_predictors` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-factor-predictors.md
- `tengu_v3_intel_darkpool_history` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-darkpool-history.md
- `tengu_v3_intel_gex_history` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-gex-history.md
- `tengu_v3_intel_ml_drivers` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-ml-drivers.md
- `tengu_v3_intel_ml_prediction` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-ml-prediction.md
- `tengu_v3_intel_options_flow_history` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-intel-options-flow-history.md
- `tengu_v3_news_sentiment_history` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-news-sentiment-history.md
- `tengu_v3_optimizer_latest` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-optimizer-latest.md
- `tengu_v3_prices_corporate_actions` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-prices-corporate-actions.md
- `tengu_v3_private_markets_service_provider_relations` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-private-markets-service-provider-relations.md
- `tengu_v3_reference_coverage` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-reference-coverage.md
- `tengu_v3_supply_chain_relationships` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-supply-chain-relationships.md
- `tengu_v3_tape_bars` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-tape-bars.md
- `tengu_v3_validation_trials` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-validation-trials.md
- `tengu_v3_workforce_layoffs` — Execute — https://policylayer.com/tools/tengu-mcp/tengu-v3-workforce-layoffs.md
- `tengu_cache_stats` — Read — https://policylayer.com/tools/tengu-mcp/tengu-cache-stats.md
- `tengu_copilot_decision_review` — Read — https://policylayer.com/tools/tengu-mcp/tengu-copilot-decision-review.md
- `tengu_copilot_live_ic_drift` — Read — https://policylayer.com/tools/tengu-mcp/tengu-copilot-live-ic-drift.md
- `tengu_copilot_macro_regime` — Read — https://policylayer.com/tools/tengu-mcp/tengu-copilot-macro-regime.md
- `tengu_copilot_score_ticker` — Read — https://policylayer.com/tools/tengu-mcp/tengu-copilot-score-ticker.md
- `tengu_copilot_signal_health` — Read — https://policylayer.com/tools/tengu-mcp/tengu-copilot-signal-health.md
- `tengu_copilot_ticker_full` — Read — https://policylayer.com/tools/tengu-mcp/tengu-copilot-ticker-full.md
- `tengu_copilot_ticker_smartmoney` — Read — https://policylayer.com/tools/tengu-mcp/tengu-copilot-ticker-smartmoney.md
- …and 306 more: https://policylayer.com/tools/tengu-mcp.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=tengu-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/tengu-mcp