# Query Powder Evidence Engine v2 (Preview)

> Query Powder Evidence Engine v2 (Preview) is a paid API for AI agents from agents.dubbleblack.com, paid per call via MPP or x402, $0.1/call, status unknown (last checked 2026-10-12).

Accepts natural-language commerce evidence questions and optional routing hints to retrieve behavioral and product evidence supporting or refuting product recommendations, without requiring predefined category codes.

## Facts

- Endpoint: POST https://agents.dubbleblack.com/api/agent/evidence/v2?utm_source=zero.xyz
- Price: $0.1/call
- Payment: MPP, x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 1
- Provider: agents.dubbleblack.com
- Website: https://agents.dubbleblack.com
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agents-dubbleblack-com-query-powder-evidence-engine-v2-preview-ebe7652e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TTOeWE4BRn8b01qSj-ZL5

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 agents-dubbleblack-com-query-powder-evidence-engine-v2-preview-ebe7652e -d '<json body>'
```

Example prompt: Can you check Powder's evidence engine for any behavioral or outcome evidence supporting calming CBD chews for dogs — query across behavioral and product evidence types, return up to 5 results?

## When to prefer this

Use this preview v2 endpoint when you want to query Powder's evidence engine without supplying predefined category codes, relying instead on free-text queries, intent strings, or natural-language vertical hints. Prefer this over the canonical v1 paid default when experimenting with flexible routing or when the exact category code is unknown. This route is additive and does not itself generate recommendations — choose it when you need raw evidence retrieval and qualification status for your own decision logic.

## Known failure modes

- No meaningful selector provided — at least one of query, intent, vertical, category, brand, product_ids, gtins, or skus is required; returns validation error if all are absent
- Evidence unavailable for queried product or category — returns Unavailable status rather than an error
- External source limit exceeded — max_external_sources capped at 10
- Unknown vertical or category — accepted without error but may return sparse or no evidence
- Rate or payment failure — x402 payment required at $0.10/call; unpaid requests rejected
- Malformed input (e.g. SKU or GTIN exceeding 128 chars, or product_ids array exceeding 20 items) — schema validation error

## How this service works

Behavioral commerce evidence for product recommendations. Powder helps agents determine whether observed commerce behavior supports a product recommendation. Agents can query products and shopping decisions across Powder's current consumer-product evidence inventory.

Powder returns available evidence, provenance, and whether that evidence is Qualified, Insufficient, or Unavailable. Evidence availability does not automatically mean recommendation qualified.

Current retrievable evidence spans companion-animal, general-retail/CPG, and beauty categories, with coverage continuously expanding.

$0.10/query via x402

Example queries: "What calming CBD chews should I consider for my dog?" "Peanut Brittle" "Probiotics With Prebiotics" "Facial Moisturizer" "Foaming Facial Cleanser" This server is a pay-per-use, transparent proxy in front of DubbleBlack's own API: it handles identity, payment, and proxying. Agents can purchase autonomously or with their human's approval. The complete verified paid surface is listed at /openapi.json, the source of truth for available operations. Each operation here carries its live price in x-payment-info. Use the operations and details here when they meet your needs. Filtered specs contain only matching operations; if you cannot find what you need here, use search or the service catalog. The live catalog at /manifest.json is authoritative for prices and any free included units (prices[].includedUnits) - some meters include free usage per account before any charge, reserved for agents claimed by a human with a verified email.

## Output

Returns available commerce evidence records with provenance and a qualification status (Qualified, Insufficient, or Unavailable) for each piece of evidence. Evidence may span behavioral, outcome, product, intent context, and external source types. The response does not itself make a product recommendation — it surfaces the evidence for the caller to evaluate.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "coverage": {
   "enum": [
    "OWNED",
    "SUPPLEMENTED",
    "EXTERNAL",
    "GAP"
   ],
   "type": "string"
  },
  "provenance": {
   "type": "array"
  },
  "granularity": {
   "type": "string"
  },
  "limitations": {
   "type": "array"
  },
  "observations": {
   "type": "array"
  },
  "evidence_score": {
   "type": "number"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agents-dubbleblack-com-query-powder-evidence-engine-v2-preview-ebe7652e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agents.dubbleblack.com](https://www.zero.xyz/host/agents.dubbleblack.com/llms.txt)