# Ask Session – Parallel Multi-Model LLM Runner

> Ask Session – Parallel Multi-Model LLM Runner is a paid API for AI agents from ask-session.withzero.ai, paid per call via MPP, $0.02/call, status unknown (last checked 2026-10-13).

Runs a single prompt against up to 5 LLMs in parallel and returns all responses, token counts, latencies, and costs in one call

## Facts

- Endpoint: POST https://ask-session.withzero.ai/run?utm_source=zero.xyz
- Price: $0.02/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Provider: ask-session.withzero.ai
- Website: https://ask-session.withzero.ai
- Canonical page: https://www.zero.xyz/c/ask-session-withzero-ai-ask-session-parallel-multi-model-llm-runner-3ef0a2ef
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_BvIVe8fkoAenqJEWHAd8E

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 ask-session-withzero-ai-ask-session-parallel-multi-model-llm-runner-3ef0a2ef -d '<json body>'
```

Example prompt: Send this prompt to GPT-4.1, Claude Sonnet 4.5, and Gemini 2.5 Pro in parallel and show me all three responses side by side: 'Explain the key tradeoffs between microservices and monolithic architectures in 3 bullet points.'

## When to prefer this

Choose this endpoint when you need to compare outputs from multiple LLMs on the same prompt in a single roundtrip, or when you want to pick the best model for a given task without running sequential calls. It is ideal for benchmarking, quality comparison, consensus checking, or any workflow where seeing 2–5 model responses side-by-side adds value. Prefer it over single-model endpoints when model diversity or redundancy matters more than minimizing cost.

## Known failure modes

- Individual model may fail (error field populated per model) while others succeed — modelsSucceeded < modelsQueried
- Prompt exceeds 10,000 character limit — validation error
- maxTokens outside 50–4096 range — validation error
- Invalid or unrecognized model ID in models array — error per affected model
- Insufficient channel deposit to cover voucher — payment rejected
- Session channel not open or expired — authentication/payment failure

## How this service works

Run a prompt against 1-5 models in parallel. Per-voucher: $0.02. Buyer opens a session channel (recommended deposit $0.05) and signs cumulative vouchers per call. Each call advances the channel by $0.02. Close the session to get unspent deposit refunded. Pre-flight: free `GET /models` lists every supported model with per-million token costs and an estimated per-call cost — use it to choose the `models` array before opening the channel.

## Output

Returns an array of per-model objects each containing the model ID, the text response, input/output token counts, latency in milliseconds, and cost in USD. Top-level fields include the original prompt, number of models queried vs succeeded, total latency, and summed token cost across all models.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "prompt"
 ],
 "properties": {
  "models": {
   "type": "array",
   "items": {
    "type": "string"
   },
   "maxItems": 5,
   "minItems": 1,
   "description": "Model IDs to query (1-5). Defaults to GPT-4.1, Claude Sonnet 4.5, Gemini 2.5 Pro. Available: openai/gpt-4.1, openai/gpt-4.1-mini, openai/gpt-4.1-nano, anthropic/claude-opus-4-6, anthropic/claude-sonnet-4-5, anthropic/claude-haiku-4-5, google/gemini-2.5-pro, google/gemini-2.5-flash, meta-llama/llama-3.3-70b-instruct, mistralai/mistral-large, mistralai/mistral-small, deepseek/deepseek-v3, deepseek/deepseek-r1"
  },
  "prompt": {
   "type": "string",
   "maxLength": 10000,
   "minLength": 1,
   "description": "The question or prompt to send to the models"
  },
  "maxTokens": {
   "type": "number",
   "default": 1024,
   "maximum": 4096,
   "minimum": 50,
   "description": "Max tokens per model response (default: 1024)"
  },
  "systemPrompt": {
   "type": "string",
   "maxLength": 2000,
   "description": "Optional system prompt to set context for all models"
  }
 },
 "additionalProperties": false
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "prompt",
  "responses",
  "modelsQueried",
  "modelsSucceeded",
  "totalLatencyMs",
  "totalCostUsd"
 ],
 "properties": {
  "prompt": {
   "type": "string"
  },
  "responses": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "model",
     "response",
     "inputTokens",
     "outputTokens",
     "latencyMs",
     "costUsd"
    ],
    "properties": {
     "error": {
      "type": "string"
     },
     "model": {
      "type": "string"
     },
     "costUsd": {
      "type": "number",
      "description": "Actual cost for this model call in USD"
     },
     "response": {
      "type": "string"
     },
     "latencyMs": {
      "type": "number"
     },
     "inputTokens": {
      "type": "number"
     },
     "outputTokens": {
      "type": "number"
     }
    },
    "additionalProperties": false
   }
  },
  "totalCostUsd": {
   "type": "number",
   "description": "Estimated raw token cost summed across all models (USD)"
  },
  "modelsQueried": {
   "type": "number"
  },
  "totalLatencyMs": {
   "type": "number"
  },
  "modelsSucceeded": {
   "type": "number"
  }
 },
 "additionalProperties": false
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ask-session-withzero-ai-ask-session-parallel-multi-model-llm-runner-3ef0a2ef/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ask-session.withzero.ai](https://www.zero.xyz/host/ask-session.withzero.ai/llms.txt)