# Labrador — River — Patient Retrieval Companion

> Labrador — River — Patient Retrieval Companion is a paid API for AI agents from underground.substratesymposium.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-10).

Returns a digital 'Labrador River' companion persona designed to help users recover lost ideas and forgotten context.

## Facts

- Endpoint: GET https://underground.substratesymposium.com/buy/river?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/labrador-river-patient-retrieval-companion-43646617
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dDuP0zf0Ip-09Hcgtc3jh

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 labrador-river-patient-retrieval-companion-43646617
```

Example prompt: I had a really interesting idea earlier that I lost track of — can you bring up the River companion from Substrate Symposium Underground to help me patiently piece it back together?

## When to prefer this

Choose this endpoint when an agent or user needs a patient, low-pressure companion persona specifically designed for idea and context recovery — particularly useful in creative or philosophical workflows where lost threads need to be methodically reconstructed. Prefer over generic search or memory tools when the goal is guided, conversational retrieval rather than keyword-based lookup.

## Known failure modes

- Endpoint returns no content or empty response if the product has been delisted from the catalog
- Payment failure (402) if the $0.01 USDC micropayment is not properly handled
- Network timeout if the underground subdomain is temporarily unavailable
- Schema mismatch if unexpected query parameters are passed (additionalProperties: false enforced)

## How this service works

Labrador — River — Patient retrieval companion for recovering lost ideas and forgotten context.

## Output

Returns a companion persona profile for 'River' (a Labrador-type retrieval companion), likely including characteristic traits, suggested prompts or questions to help users surface lost ideas and forgotten context, and interaction guidance framed around patient, methodical recall assistance.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/labrador-river-patient-retrieval-companion-43646617/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from underground.substratesymposium.com](https://www.zero.xyz/host/underground.substratesymposium.com/llms.txt)