# PromptQualityScore Preflight Check

> PromptQualityScore Preflight Check is a paid API for AI agents from promptqualityscore.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Runs a quick pass/fail pre-flight check on a prompt's quality and optionally validates an endpoint's on-chain trust signals before committing to a paid LLM call.

## Facts

- Endpoint: GET https://promptqualityscore.com/api/preflight
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/promptqualityscore-com-4a94b2c8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7CeGqpG6hq_taOF7p54KW

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 promptqualityscore-com-4a94b2c8
```

Example prompt: Before I send this to Claude, run a preflight quality check on my prompt — 'Summarize the key financial risks in this 10-K filing and output structured JSON' — and also pull the trust signals for the target endpoint so I know if it's worth the spend.

## When to prefer this

Use this endpoint when running autonomous agents or pipelines that make paid LLM calls and need a cheap circuit breaker to avoid wasting budget on low-quality prompts or untrustworthy endpoints. Ideal before any call to a metered LLM API where prompt quality directly affects output value. Preferred over full scoring endpoints when speed and cost matter and a simple pass/fail verdict is sufficient.

## Known failure modes

- Prompt text missing or empty — returns 400 with validation error
- Target endpoint URL malformed — trust signal lookup fails with 422
- Payment not attached or insufficient — returns 402 Payment Required
- Prompt exceeds length limits — truncation or rejection error
- On-chain data unavailable for endpoint — trust signals section returns null or empty
- Service timeout on LLM-backed sub-scoring — partial results or 503

## How this service works

A Quality Gate For Prompts. Before they break production. Score any AI prompt against 8 dimensions, see what's weak, and get the fixed version in seconds.

## Output

Returns a pass/fail verdict based on a quality threshold (pass at 28/80 by default), a composite score (0-100), a letter grade (A-F), sub-scores across multiple prompt quality frameworks (e.g. PEEM), and optionally the target endpoint's on-chain trust metrics including total payments received, number of unique payers, and last activity timestamp.

## Example request

```json
{
 "input": {
  "body": {
   "prompt": "Summarize the key financial risks in this 10-K filing and output structured JSON",
   "vertical": "business",
   "endpoint_url": "https://api.example.com/llm-endpoint"
  },
  "type": "http",
  "method": "GET",
  "bodyType": "json",
  "pathParams": {}
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "prompt": {
   "type": "string",
   "maxLength": 10000,
   "minLength": 1,
   "description": "Prompt to preflight"
  },
  "vertical": {
   "enum": [
    "software",
    "content",
    "business",
    "education",
    "science",
    "crypto",
    "general",
    "research"
   ],
   "type": "string",
   "default": "general",
   "description": "Domain: software/content/business/education/science/crypto/general/research"
  },
  "endpoint_url": {
   "type": "string",
   "description": "Optional endpoint URL for trust scoring"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "prompt": {
   "grade": "C",
   "score": 46,
   "out_of": 80,
   "feedback": [
    "Specify the exact output format you want (bullets, JSON, prose).",
    "Name the target reader or persona explicitly.",
    "Add one concrete example of the ideal response."
   ],
   "top_issue": "Specify the exact output format you want (bullets, JSON, prose).",
   "dimensions": {
    "total": 46,
    "clarity": 7,
    "context": 6,
    "examples": 4,
    "constraints": 5,
    "specificity": 6,
    "cot_structure": 6,
    "output_format": 7,
    "role_definition": 5
   },
   "threshold_met": true
  },
  "endpoint": {
   "wallet": "0xD2DfC5796de622E08C13f3016E92cfa15Ea33D0F",
   "trust_label": "Established",
   "trust_score": 0.78,
   "resolution_source": "well_known"
  },
  "clearance": "CAUTION",
  "confidence": 0.68,
  "pqs_version": "2.0",
  "upgrade_url": "https://promptqualityscore.com"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/promptqualityscore-com-4a94b2c8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from promptqualityscore.com](https://www.zero.xyz/host/promptqualityscore.com/llms.txt)