# RelayStation LLM Answer — Grounded Q&A from Context

> RelayStation LLM Answer — Grounded Q&A from Context is a paid API for AI agents from api.relaystation.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Answers a specific question strictly from the provided context text using a high-accuracy LLM, with no hallucinated sources and tiered model selection.

## Facts

- Endpoint: POST https://api.relaystation.ai/v1/llm/answer
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/relaystation-llm-answer-grounded-q-a-from-context-b62e143d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rCTKH34SV9_qDHMx_9W9G

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 relaystation-llm-answer-grounded-q-a-from-context-b62e143d -d '<json body>'
```

Example prompt: Using the value tier, answer this question strictly from the context I'm giving you — 'What are the refund terms?' — based on this text: 'All purchases are final except within 30 days of delivery, at which point a full refund is issued.' Don't add anything that isn't in the text.

## When to prefer this

Choose this endpoint when you need a reliable, cost-efficient grounded answer from a specific text passage — especially in RAG pipelines where hallucination must be prevented. It offers near-Opus-4.8 accuracy at 1–5% of the cost with tiered model selection (budget/value/best), making it ideal for high-volume document QA, customer support automation, and contract analysis where staying strictly within provided context is critical. Prefer it over general LLM APIs when auditability, cost transparency per-call, and source grounding are required.

## Known failure modes

- Missing `input` or `question` field returns a validation error
- Context too long may cause truncation (truncated=true) with charge still applied
- Invalid tier enum value causes request rejection
- Empty or whitespace-only input/question fails minLength validation
- Network or upstream provider errors may return 5xx responses
- Insufficient x402 payment balance results in payment authorization failure

## How this service works

Provider cost + 6%, itemized. Answer a question strictly from the context you provide — grounded, no hallucinated sources. ≈Opus-4.8 accuracy at ~1–5% of its cost (benchmark: relaystation.ai/llm-validation). 1¢ x402 min; remainder auto-credits — relaystation.ai/penny

## Output

Returns a JSON object with a `result` string (the answer grounded to the provided context), a `truncated` boolean indicating if the output hit the token cap, and a `usage` object detailing the model name, input/output token counts, provider cost in micros, markup percentage, actual charged micros, and the authorized ceiling micros.

## 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": {
     "type": "object",
     "properties": {
      "tier": {
       "enum": [
        "budget",
        "value",
        "best"
       ],
       "type": "string"
      },
      "input": {
       "type": "string",
       "minLength": 1,
       "description": "The text to process (DATA — never interpolated into the instruction)."
      },
      "params": {
       "type": "object",
       "required": [
        "question"
       ],
       "properties": {
        "question": {
         "type": "string",
         "minLength": 1
        }
       },
       "description": "Task-specific params for 'answer', validated against the task's param_schema."
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "result",
      "truncated",
      "usage"
     ],
     "properties": {
      "usage": {
       "type": "object",
       "required": [
        "model",
        "inputTokens",
        "outputTokens",
        "providerCostMicros",
        "markupPct",
        "chargedMicros",
        "ceilingMicros"
       ],
       "properties": {
        "model": {
         "type": "string"
        },
        "markupPct": {
         "type": "number"
        },
        "inputTokens": {
         "type": "integer"
        },
        "outputTokens": {
         "type": "integer"
        },
        "ceilingMicros": {
         "type": "integer",
         "description": "The authorized ceiling the 402/hold reserved."
        },
        "chargedMicros": {
         "type": "integer",
         "description": "The actual charged amount (<= ceiling)."
        },
        "providerCostMicros": {
         "type": "integer"
        }
       }
      },
      "result": {
       "type": "string",
       "description": "The task output text (or JSON st
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/relaystation-llm-answer-grounded-q-a-from-context-b62e143d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.relaystation.ai](https://www.zero.xyz/host/api.relaystation.ai/llms.txt)