# Halowerk Entity Monitor – UK Companies House Search & Filing Tracker

> Halowerk Entity Monitor – UK Companies House Search & Filing Tracker is a paid API for AI agents from finanz.halowerk.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Searches UK companies by name or monitors a specific company's Companies House profile and filing history, returning new filings since a given baseline transaction ID or filing date.

## Facts

- Endpoint: POST https://finanz.halowerk.com/v1/entity-monitor
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-entity-monitor-uk-companies-house-search-filing-tracker-559e8a65
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_G1-ngd4q-sOQToJMjmnw4

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability halowerk-entity-monitor-uk-companies-house-search-filing-tracker-559e8a65 -d '<json body>'
```

Example prompt: Check Companies House for 'Revolut Ltd' and tell me if there are any new filings since transaction ID abc123xyz — I want to know what's changed since that baseline.

## When to prefer this

Choose this endpoint when you need to search for UK-registered companies by name or track changes to a specific company's Companies House filing record since a known checkpoint. It is purpose-built for UK corporate registry data with built-in change detection, making it superior to generic web scraping or raw Companies House API calls for agent-based monitoring workflows. Not suitable for non-UK companies, SEC filings, or subscription-based push alerts.

## Known failure modes

- Company not found on Companies House — returns empty results or not-found flag
- Baseline transaction ID or filing date not matched in filing history — baseline-found flag set to false
- Rate limit approached — requests are throttled below Companies House ceiling of 600 per 5 minutes
- Invalid or missing mode parameter — request rejected or undefined behavior
- Network or Companies House API unavailability — upstream error returned

## How this service works

In search mode, finds UK companies by name. In monitor mode, fetches the current company profile and filing history and compares it with the transaction id or filing date supplied by the caller. The response states whether the baseline was found and lists filings newer than that baseline. This is a pull comparison, not a subscription or push alert. Requests are rate-limited in code below the Companies House ceiling of 600 requests per five minutes.

## Output

In search mode: a list of UK companies matching the provided name. In monitor mode: the company's current Companies House profile, its filing history, a flag indicating whether the supplied baseline (transaction ID or filing date) was found, and a list of filings newer than that baseline.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "limit": {
   "type": "integer",
   "default": 20,
   "maximum": 50,
   "minimum": 1
  },
  "query": {
   "type": "string",
   "maxLength": 200,
   "minLength": 2,
   "description": "Company name for action=search."
  },
  "action": {
   "enum": [
    "search",
    "monitor"
   ],
   "type": "string"
  },
  "company_number": {
   "type": "string",
   "maxLength": 10,
   "minLength": 6,
   "description": "Companies House number for action=monitor."
  },
  "known_filing_date": {
   "type": "string",
   "format": "date",
   "description": "Fallback baseline date, YYYY-MM-DD."
  },
  "known_latest_transaction_id": {
   "type": "string",
   "maxLength": 100,
   "minLength": 2,
   "description": "Last transaction id seen by the caller."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-entity-monitor-uk-companies-house-search-filing-tracker-559e8a65/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from finanz.halowerk.com](https://www.zero.xyz/host/finanz.halowerk.com/llms.txt)