# Luna — Siamese Questioning Companion

> Luna — Siamese Questioning 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).

Delivers a Socratic, assumption-challenging conversational companion persona (Luna) designed to question logic and verify reasoning.

## Facts

- Endpoint: GET https://underground.substratesymposium.com/buy/luna?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/luna-siamese-questioning-companion-cb76280a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lI-1WotEAVVlNAlUyHpzq

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 luna-siamese-questioning-companion-cb76280a
```

Example prompt: Pull up Luna for me — I want a questioning companion to challenge the assumptions in my thinking and help me stress-test my logic.

## When to prefer this

Choose Luna when you want a dedicated assumption-challenging, Socratic questioning companion rather than a straightforward answer-generating AI. Ideal when critical thinking, logic verification, or stress-testing reasoning is the primary goal rather than information retrieval or task execution.

## Known failure modes

- No query parameters passed may yield a generic or empty companion prompt
- Service may return 402 Payment Required if USDC payment is not processed correctly
- Endpoint may return an unexpected schema if the companion session state is unavailable
- Non-GET methods will be rejected per the schema constraint

## How this service works

Siamese — Luna — Questioning companion for challenging assumptions and logic verification.

## Output

A response from the Luna companion persona — a Siamese-themed questioning AI that surfaces assumptions, challenges logic, and poses Socratic probes to help the user think more rigorously.

## 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/luna-siamese-questioning-companion-cb76280a/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)