# property_value_history

Get property value history and tax assessment trends over multiple years. Shows year-by-year market value, land value, improvement value, and percentage change. Use this for questions like "how has this property's value changed?", "what's the appreciation rate?", "show me the tax assessment history", "has this home gone up in value?", or any property valuation trend question. Requires account number (use property_lookup first to find it).

Agent View of the PolicyLayer registry record for `property_value_history`. HTML page: https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/property-value-history

## Facts

- Tool: `property_value_history`
- 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: 2 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `county` | string | no | County name (default: montgomery) |
| `account_number` | string | yes | County appraisal district account number |

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": "property_value_history",
    "arguments": {
      "account_number": "<account_number>"
    }
  }
}
```

## Why property_value_history is rated Low

This tool retrieves historical property valuation and tax assessment data without creating, modifying, deleting, or executing any operations. It answers analytical questions about property appreciation trends. The dependency on property_lookup for account numbers and the read-only nature of querying historical values confirm this is a data retrieval operation with minimal blast radius if misused by an AI agent.

From the tool's own definition: "Tool description explicitly states it 'Get[s] property value history and tax assessment trends' and 'Shows year-by-year market value' — pure data retrieval with no modification, deletion, or execution of external operations."

## Use case

AI agents call property_value_history 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": {
    "property_value_history": {}
  }
}
```

## Other tools on Livedatalink (279)

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- `cdc_dataset_query` — Execute — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/cdc-dataset-query.md
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- `air_quality` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/air-quality.md
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- `book_details` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/book-details.md
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- `book_get_text` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/book-get-text.md
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- `book_status` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/book-status.md
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- `caselaw_citation_lookup` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/caselaw-citation-lookup.md
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- `caselaw_search` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/caselaw-search.md
- `cdc_drug_overdose_deaths` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/cdc-drug-overdose-deaths.md
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- `cdc_leading_causes_of_death` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/cdc-leading-causes-of-death.md
- `cdc_outbreak_reports` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/cdc-outbreak-reports.md
- `cdc_vaccination_coverage` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/cdc-vaccination-coverage.md
- `cdc_weekly_deaths_by_state` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/cdc-weekly-deaths-by-state.md
- `census_business` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/census-business.md
- `census_commute_employment` — Read — https://policylayer.com/tools/io-github-blackboxfoundry-livedatalink/census-commute-employment.md
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- …and 249 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