# get_bgp_pfx2as

Get prefix-to-ASN mapping. Useful for looking up which AS announces a given IP prefix.

Agent View of the PolicyLayer registry record for `get_bgp_pfx2as`. HTML page: https://policylayer.com/tools/cloudflare/get-bgp-pfx2as

## Facts

- Tool: `get_bgp_pfx2as`
- Server: Cloudflare (`https://builds.mcp.cloudflare.com/sse`) — https://policylayer.com/tools/cloudflare.md
- Homepage: https://github.com/cloudflare/mcp-server-cloudflare
- Risk category: Read (Low risk)
- Registry record: grade D, identity verified
- Server auth posture: gated
- 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": "get_bgp_pfx2as",
    "arguments": {}
  }
}
```

## Why get_bgp_pfx2as is rated Low

This tool retrieves BGP prefix-to-ASN mapping information from a read-only query. It performs a lookup of which autonomous system announces a given IP prefix—a passive information retrieval operation with no capability to modify, delete, execute code, or commit financial transactions. The blast radius of misuse is minimal, limited to information disclosure about network routing topology.

From the tool's own definition: "Tool name 'get_bgp_pfx2as' and description 'Get prefix-to-ASN mapping' indicate a query/lookup operation. The verb 'Get' and phrase 'looking up' confirm data retrieval with no side effects."

## Use case

AI agents call get_bgp_pfx2as to retrieve information from Cloudflare 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 Cloudflare:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "get_bgp_pfx2as": {}
  }
}
```

## Other tools on Cloudflare (91)

- `container_file_delete` — Destructive — https://policylayer.com/tools/cloudflare/container-file-delete.md
- `container_exec` — Execute — https://policylayer.com/tools/cloudflare/container-exec.md
- `container_initialize` — Execute — https://policylayer.com/tools/cloudflare/container-initialize.md
- `dex_create_remote_pcap` — Execute — https://policylayer.com/tools/cloudflare/dex-create-remote-pcap.md
- `dex_create_remote_warp_diag` — Execute — https://policylayer.com/tools/cloudflare/dex-create-remote-warp-diag.md
- `container_file_read` — Read — https://policylayer.com/tools/cloudflare/container-file-read.md
- `container_files_list` — Read — https://policylayer.com/tools/cloudflare/container-files-list.md
- `container_ping` — Read — https://policylayer.com/tools/cloudflare/container-ping.md
- `dex_analyze_warp_diag` — Read — https://policylayer.com/tools/cloudflare/dex-analyze-warp-diag.md
- `dex_explore_remote_warp_diag_output` — Read — https://policylayer.com/tools/cloudflare/dex-explore-remote-warp-diag-output.md
- `dex_fleet_status_live` — Read — https://policylayer.com/tools/cloudflare/dex-fleet-status-live.md
- `dex_fleet_status_logs` — Read — https://policylayer.com/tools/cloudflare/dex-fleet-status-logs.md
- `dex_fleet_status_over_time` — Read — https://policylayer.com/tools/cloudflare/dex-fleet-status-over-time.md
- `dex_http_test_details` — Read — https://policylayer.com/tools/cloudflare/dex-http-test-details.md
- `dex_list_colos` — Read — https://policylayer.com/tools/cloudflare/dex-list-colos.md
- `dex_list_remote_capture_eligible_devices` — Read — https://policylayer.com/tools/cloudflare/dex-list-remote-capture-eligible-devices.md
- `dex_list_remote_captures` — Read — https://policylayer.com/tools/cloudflare/dex-list-remote-captures.md
- `dex_list_remote_warp_diag_contents` — Read — https://policylayer.com/tools/cloudflare/dex-list-remote-warp-diag-contents.md
- `dex_list_tests` — Read — https://policylayer.com/tools/cloudflare/dex-list-tests.md
- `dex_list_warp_change_events` — Read — https://policylayer.com/tools/cloudflare/dex-list-warp-change-events.md
- `dex_test_statistics` — Read — https://policylayer.com/tools/cloudflare/dex-test-statistics.md
- `dex_traceroute_test_details` — Read — https://policylayer.com/tools/cloudflare/dex-traceroute-test-details.md
- `dex_traceroute_test_network_path` — Read — https://policylayer.com/tools/cloudflare/dex-traceroute-test-network-path.md
- `dex_traceroute_test_result_network_path` — Read — https://policylayer.com/tools/cloudflare/dex-traceroute-test-result-network-path.md
- `dns_report` — Read — https://policylayer.com/tools/cloudflare/dns-report.md
- `get_ai_data` — Read — https://policylayer.com/tools/cloudflare/get-ai-data.md
- `get_annotations` — Read — https://policylayer.com/tools/cloudflare/get-annotations.md
- `get_as_details` — Read — https://policylayer.com/tools/cloudflare/get-as-details.md
- `get_as_relationships` — Read — https://policylayer.com/tools/cloudflare/get-as-relationships.md
- `get_as_set` — Read — https://policylayer.com/tools/cloudflare/get-as-set.md
- …and 61 more: https://policylayer.com/tools/cloudflare.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=cloudflare · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/cloudflare