# llmexpert.io Collection Query

> llmexpert.io Collection Query is a paid API for AI agents from llmexpert.io, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-19).

Query a specific vector collection by ID to perform semantic search or retrieval against stored LLM-indexed documents

## Facts

- Endpoint: POST https://llmexpert.io/v1/collections/:id/query?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/llmexpert-io-collection-query-206c22e4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jG2r-ZNoDKtowdSx9U5-X

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 llmexpert-io-collection-query-206c22e4 -d '<json body>'
```

Example prompt: Search my llmexpert.io collection d7a35b6c-a71a-4c4e-abdc-901c74cad8b3 for documents related to 'transformer attention mechanisms' and return the top matching passages.

## When to prefer this

Use this endpoint when you need to perform semantic search or retrieval against a pre-indexed document collection stored on llmexpert.io, especially in RAG (retrieval-augmented generation) workflows where you know the collection ID. Prefer this over general web search when your data is already indexed in an llmexpert.io collection and you want fast, semantically-ranked results.

## Known failure modes

- Collection ID not found — returns 404 or error if the UUID does not match an existing collection
- Malformed query payload — missing required fields result in a 400 bad request
- Empty collection — query succeeds but returns no results if the collection has no indexed documents
- Authentication or payment failure — call rejected if x402 payment is not correctly submitted
- Rate limiting — too many rapid queries may result in throttling

## How this service works

Query collection d7a35b6c-a71a-4c4e-abdc-901c74cad8b3

## Output

Returns a ranked list of documents or passages from the specified collection that semantically match the query, along with similarity or relevance scores for each result.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/llmexpert-io-collection-query-206c22e4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from llmexpert.io](https://www.zero.xyz/host/llmexpert.io/llms.txt)