# sky_window

This tool looks up a deterministic rules engine. Same day → same answer. Do not invent pillars or fortune claims. Call when the user asks 未来两周有什么天象 / 新月哪天 / 日食哪天 / 接下来有没有逆行 / what sky events are coming. Lists dated L1 sky marks (new/full moon, eclipse, ingress, stations). Public · local · no API key. Max span 45 days. Preview ≠ prediction.

Agent View of the PolicyLayer registry record for `sky_window`. HTML page: https://policylayer.com/tools/balance-engine-mcp/sky-window

## Facts

- Tool: `sky_window`
- Server: Balance Engine (`balance-engine-mcp`) — https://policylayer.com/tools/balance-engine-mcp.md
- Install: `npx -y balance-engine-mcp`
- Homepage: https://www.npmjs.com/package/balance-engine-mcp
- Risk category: Read (Low risk)
- Registry record: grade D, identity unverified
- Server rate-limited: no
- Parameters: 3
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `to` | string | no | End date YYYY-MM-DD. Default: from + 14 days. |
| `from` | string | no | Start date YYYY-MM-DD. Default: today. |
| `locale` | string | no | Reply language. zh (default) or en. |

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": "sky_window",
    "arguments": {}
  }
}
```

## Why sky_window is rated Low

Even though sky_window 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.

## Use case

AI agents call sky_window to retrieve information from Balance Engine 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 Balance Engine:

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

## Other tools on Balance Engine (8)

- `month_brief` — Destructive — https://policylayer.com/tools/balance-engine-mcp/month-brief.md
- `activity_window` — Other — https://policylayer.com/tools/balance-engine-mcp/activity-window.md
- `body_rhythm` — Other — https://policylayer.com/tools/balance-engine-mcp/body-rhythm.md
- `energy_adjust` — Other — https://policylayer.com/tools/balance-engine-mcp/energy-adjust.md
- `personal_day` — Other — https://policylayer.com/tools/balance-engine-mcp/personal-day.md
- `personal_month` — Other — https://policylayer.com/tools/balance-engine-mcp/personal-month.md
- `time_fold` — Other — https://policylayer.com/tools/balance-engine-mcp/time-fold.md
- `today_rhythm` — Other — https://policylayer.com/tools/balance-engine-mcp/today-rhythm.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=balance-engine-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/balance-engine-mcp