# security_fetch_package_licence

Fetch the SPDX licence identifier for an open source package version. Read-only. No side effects. Idempotent. package: Package name e.g. flask. Required. version: Exact version string e.g. 2.3.0. Required. ecosystem: One of PyPI, npm, Maven, Go, Cargo, NuGet, RubyGems. Required. Returns the SPDX licence identifier e.g. MIT, Apache-2.0, GPL-3.0. Use this to verify licence compatibility before including a dependency. Use security_fetch_package_vulnerabilities instead when checking for security issues not licences. Verified source: deps.dev (Google). 1-hour cache. If this tool's response does not serve the user's need, call report_feedback with feedback_type="agent_gap", tool_id="security_fetch_package_licence", intended_query="{what the user needed}", gap_description="{what was missing or wrong in the result}".

Agent View of the PolicyLayer registry record for `security_fetch_package_licence`. HTML page: https://policylayer.com/tools/dev-7bd0-mcp-server/security-fetch-package-licence

## Facts

- Tool: `security_fetch_package_licence`
- Server: DataNexus MCP (`dev-7bd0/mcp-server`) — https://policylayer.com/tools/dev-7bd0-mcp-server.md
- Homepage: https://github.com/dev-7bd0/mcp-server
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 3
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `package` | string | no | Package name e.g. requests. Required. |
| `version` | string | no | Package version e.g. 2.28.0. Required. |
| `ecosystem` | string | no | Package ecosystem: npm, pypi, cargo, go, maven, nuget. Required. |

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": "security_fetch_package_licence",
    "arguments": {}
  }
}
```

## Why security_fetch_package_licence is rated Low

This tool queries dependency licence metadata without triggering side effects. It retrieves immutable, publicly available security/compliance data (SPDX identifiers). The description explicitly confirms read-only semantics and idempotency, placing it firmly in the Read category with low severity (minimal blast radius if misused—worst case is incorrect compliance decisions based on wrong licence data, but no…

From the tool's own definition: "'Read-only. No side effects. Idempotent.' Fetches and returns SPDX licence identifier for a package version from verified source (deps.dev). No data creation, modification, deletion, code execution, or financial operations."

## Use case

AI agents call security_fetch_package_licence to retrieve information from DataNexus MCP 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 DataNexus MCP:

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

## Other tools on DataNexus MCP (54)

- `apikeys_revoke_api_key` — Destructive — https://policylayer.com/tools/dev-7bd0-mcp-server/apikeys-revoke-api-key.md
- `apikeys_rotate_api_key` — Destructive — https://policylayer.com/tools/dev-7bd0-mcp-server/apikeys-rotate-api-key.md
- `compliance_check_sam_exclusion` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/compliance-check-sam-exclusion.md
- `compliance_fetch_finra_broker` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/compliance-fetch-finra-broker.md
- `compliance_fetch_npi_provider` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/compliance-fetch-npi-provider.md
- `compliance_search_npi_by_name` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/compliance-search-npi-by-name.md
- `domain_check_email_security` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/domain-check-email-security.md
- `domain_fetch_dns_records` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/domain-fetch-dns-records.md
- `domain_fetch_domain_history` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/domain-fetch-domain-history.md
- `domain_fetch_domain_rdap` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/domain-fetch-domain-rdap.md
- `domain_fetch_reverse_ip` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/domain-fetch-reverse-ip.md
- `domain_fetch_ssl_certificate_chain` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/domain-fetch-ssl-certificate-chain.md
- `domain_fetch_subdomains` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/domain-fetch-subdomains.md
- `frontend_security_audit_ci_pipeline` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/frontend-security-audit-ci-pipeline.md
- `frontend_security_audit_manifest` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/frontend-security-audit-manifest.md
- `frontend_security_detect_typosquatting` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/frontend-security-detect-typosquatting.md
- `frontend_security_fetch_package_risk_brief` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/frontend-security-fetch-package-risk-brief.md
- `govcon_fetch_open_solicitations` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/govcon-fetch-open-solicitations.md
- `govcon_fetch_vendor_contract_history` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/govcon-fetch-vendor-contract-history.md
- `govcon_search_contract_awards` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/govcon-search-contract-awards.md
- `legal_fetch_inventor_portfolio` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/legal-fetch-inventor-portfolio.md
- `legal_fetch_patent_by_number` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/legal-fetch-patent-by-number.md
- `legal_fetch_patent_citations` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/legal-fetch-patent-citations.md
- `legal_search_patents_by_keyword` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/legal-search-patents-by-keyword.md
- `nonprofit_fetch_charity_uk` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/nonprofit-fetch-charity-uk.md
- `nonprofit_fetch_nonprofit_by_ein` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/nonprofit-fetch-nonprofit-by-ein.md
- `nonprofit_fetch_nonprofit_financial_trends` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/nonprofit-fetch-nonprofit-financial-trends.md
- `nonprofit_fetch_nonprofit_full_profile` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/nonprofit-fetch-nonprofit-full-profile.md
- `nonprofit_search_nonprofits_by_category` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/nonprofit-search-nonprofits-by-category.md
- `nonprofit_search_nonprofits_by_name` — Read — https://policylayer.com/tools/dev-7bd0-mcp-server/nonprofit-search-nonprofits-by-name.md
- …and 24 more: https://policylayer.com/tools/dev-7bd0-mcp-server.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=dev-7bd0-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/dev-7bd0-mcp-server