# fed_z1_change

Calculate the absolute and percentage change in one curated Federal Reserve Z.1 aggregate between two exact hosted quarters. Returns both observations, dollar change, percent change, series definitions, release provenance, and source hashes. Use this for 'how much did household net worth change from 2019 Q4 to 2024 Q4?', 'growth in mortgage debt since 2020', or 'change in federal debt outstanding between two quarters'. This is descriptive historical arithmetic, not a forecast or recommendation.

Agent View of the PolicyLayer registry record for `fed_z1_change`. HTML page: https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/fed-z1-change

## Facts

- Tool: `fed_z1_change`
- Server: Livedatalink (`https://livedatalink.ai/mcp`) — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink.md
- Homepage: https://github.com/blackboxfoundry/livedatalink
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server CORS policy: *
- Server rate-limited: no
- Parameters: 4 (3 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `series` | string | yes | Exact curated slug or official Z.1 series ID. Call fed_z1_catalog to discover supported values. |
| `end_period` | string | yes | Quarter in official Z.1 YYYY:Qn form, such as 2020:Q4. |
| `start_period` | string | yes | Quarter in official Z.1 YYYY:Qn form, such as 2020:Q4. |
| `response_format` | string | no | Human-readable markdown or machine-readable JSON. Default markdown. |

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": "fed_z1_change",
    "arguments": {
      "series": "<series>",
      "end_period": "<end_period>",
      "start_period": "<start_period>"
    }
  }
}
```

## Why fed_z1_change is rated Low

Even though fed_z1_change 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 fed_z1_change to retrieve information from Livedatalink 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 Livedatalink:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "fed_z1_change": {}
  }
}
```

## Other tools on Livedatalink (380)

- `beneficial_owner_screen` — Destructive — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/beneficial-owner-screen.md
- `bea_state_economic_profile` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bea-state-economic-profile.md
- `bts_transport_border_activity_pack` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bts-transport-border-activity-pack.md
- `cftc_cot_evidence_pack` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/cftc-cot-evidence-pack.md
- `clinical_site_selector` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/clinical-site-selector.md
- `edgar_recent_filings` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/edgar-recent-filings.md
- `entity_dossier` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/entity-dossier.md
- `fed_board_h15_evidence_pack` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/fed-board-h15-evidence-pack.md
- `fed_board_h15_yield_curve` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/fed-board-h15-yield-curve.md
- `govinfo_legislation_committee_path` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/govinfo-legislation-committee-path.md
- `govinfo_legislation_evidence_pack` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/govinfo-legislation-evidence-pack.md
- `patent_recent` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/patent-recent.md
- `treasury_tic_official_share` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/treasury-tic-official-share.md
- `trials_details` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/trials-details.md
- `usda_nass_crop_evidence_pack` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/usda-nass-crop-evidence-pack.md
- `affordable_housing_refinance_evidence_pack` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/affordable-housing-refinance-evidence-pack.md
- `air_quality` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/air-quality.md
- `bank_health_report` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bank-health-report.md
- `bea_compare_states` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bea-compare-states.md
- `bea_search_state_indicators` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bea-search-state-indicators.md
- `bea_state_economic_trend` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bea-state-economic-trend.md
- `bls_indicator` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bls-indicator.md
- `bls_series` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bls-series.md
- `book_details` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/book-details.md
- `book_fulltext_search` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/book-fulltext-search.md
- `book_get_text` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/book-get-text.md
- `book_search` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/book-search.md
- `book_status` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/book-status.md
- `bounce_scanner` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bounce-scanner.md
- `bts_transport_border_trend` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/bts-transport-border-trend.md
- …and 350 more: https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink.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-blackboxfoundry-livedatalink · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-blackboxfoundry-livedatalink