# CSV Duplicate Key Check

> CSV Duplicate Key Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Detects duplicate composite keys in CSV data rows using caller-supplied column names, returning counts and normalized findings as versioned deterministic JSON.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/csv-duplicate-key-check
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/csv-duplicate-key-check-b29a4dc2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7EhVGO2h_0gIG_BcN_Uol

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 csv-duplicate-key-check-b29a4dc2 -d '<json body>'
```

Example prompt: Check my CSV data for duplicate composite keys using the columns 'order_id' and 'product_sku' — I need to catch any repeated key combinations before I send this batch to the fulfillment system.

## When to prefer this

Use this endpoint when an agent needs to validate CSV uniqueness constraints on composite keys before handing structured data to a downstream system with strict deduplication requirements. Prefer this over manual row comparison when the CSV is bounded in size (under 8192 chars), no external database or service is available, and a deterministic versioned result is needed for audit or contract purposes.

## Known failure modes

- CSV text exceeds 8192 character limit — request rejected
- key_columns references column names not present in the CSV header — returns empty or error finding
- Malformed CSV (unquoted commas, inconsistent columns) may cause incorrect row parsing
- Empty CSV or CSV with only a header row returns zero duplicates with no error
- key_columns array is empty — behavior undefined or returns trivial result

## How this service works

CSV Duplicate Key Check: CSV Duplicate Key Check finds duplicate composite keys in CSV rows from bounded caller-supplied values without an external provider. Call CSV Duplicate Key Check before an agent hands structured data or a batch plan to a downstream tool with a stricter contract. Returns the bounded transformation or validation finding with counts, normalized values, and a versioned result contract for CSV Duplicate Key Check as versioned deterministic JSON. Price: $0.001 USDC via x402 o…

## Output

Returns versioned deterministic JSON containing duplicate composite key findings, including counts of occurrences per duplicate key combination, normalized key values, and a versioned result contract indicating whether duplicates were found and their details.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string",
   "maxLength": 8192,
   "description": "Text supplied to CSV Duplicate Key Check; used only for this bounded calculation and processed in memory without retention."
  },
  "key_columns": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Key Columns supplied to CSV Duplicate Key Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "unique": false,
   "duplicate_rows": [
    3
   ]
  },
  "schema": "delx/util-csv-duplicate-key-check/v1",
  "status": "advisory",
  "evidence": {
   "retained": false,
   "input_sha256": "9046a42812db7833761b9aee29de477ebae24f4c8ae2087d757d328905d6db58",
   "external_calls": 0
  },
  "operation": "data_batch:csv_duplicate_key_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/csv-duplicate-key-check-b29a4dc2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)