# Concordance Digest

> Concordance Digest is a paid API for AI agents from concordancehq.duckdns.org, paid per call via x402, $0.03/call, status unknown (last checked 2026-09-13).

Returns a cross-category digest of where a topic appears across 18 independent data sources (news, SEC filings, court opinions, academic papers, economic indicators, stock quotes, trade data, government records), grouped by category with source citations.

## Facts

- Endpoint: POST https://concordancehq.duckdns.org/tools/digest
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/concordance-digest-50339d9f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0iCSMRFswkvLMRStK38Ns

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 concordance-digest-50339d9f -d '<json body>'
```

Example prompt: Pull me a full cross-category digest on 'PFAS contamination' — I want to see where it shows up across news, court opinions, SEC filings, government records, and any other sources Concordance tracks, with the actual source citations grouped by category.

## When to prefer this

Choose this endpoint when you need to understand the breadth of coverage for a topic across heterogeneous source types simultaneously — rather than searching a single domain. Ideal for due diligence, policy research, or journalism where you need to know whether a topic is appearing in legal, financial, academic, and regulatory channels at once. Prefer over the /search endpoint when you want category-grouped aggregation rather than a flat ranked result list. Prefer over /company_brief when your subject is a topic or concept rather than a specific named company.

## Known failure modes

- Topic not found in any category returns empty categories array with zero counts
- Malformed or missing topic parameter returns HTTP 400 error
- Payment not attached or insufficient USDC (requires $0.03) returns HTTP 402
- Data freshness lag: sources are refreshed on a schedule, not live-proxied, so very recent events may not appear
- Rate limiting or service unavailability returns HTTP 429 or 503

## How this service works

One call, every category: pulls everything matching a topic across all aggregated sources and groups it by category (news, legal, academic, dev community, ...) with counts -- replaces manually calling /tools/search once per category and merging results yourself. Structured aggregation, not an AI-generated summary.

## Output

A JSON object with a topic field, an array of category objects each containing the category name, result count, and top results with URL, title, source identifier, content snippet, and publication date. Results are pre-grouped by source category (e.g. legal, filings, news) so the agent can see the distribution of coverage across domains at a glance.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "since": {
   "type": "string"
  },
  "topic": {
   "type": "string"
  },
  "per_category_limit": {
   "type": "integer"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "topic": "cryptocurrency regulation",
  "categories": [
   {
    "count": 2,
    "category": "legal",
    "top_results": [
     {
      "url": "https://www.regulations.gov/document/EPA-HQ-OAR-2022-0985-3228",
      "title": "Tracking electricity consumption from U.S. cryptocurrency mining",
      "source": "regulations_gov",
      "content": "IN-DEPTH ANALYSIS cryptocurrency mining",
      "published_at": "2024-04-22T04:00:00Z"
     }
    ]
   }
  ],
  "total_count": 4
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/concordance-digest-50339d9f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from concordancehq.duckdns.org](https://www.zero.xyz/host/concordancehq.duckdns.org/llms.txt)