# GLM-5.1 Metered Chat (Large Context)

> GLM-5.1 Metered Chat (Large Context) is a paid API for AI agents from x402.telnyx.com, paid per call via x402, $0.104493/call, status unknown (last checked 2026-10-15).

Pay-per-call OpenAI-compatible chat completions using GLM-5.1-FP8 reasoning model with metered (large-context) pricing via Telnyx Inference

## Facts

- Endpoint: POST https://x402.telnyx.com/v1/chat/completions/_t/glm/upto?utm_source=zero.xyz
- Price: $0.104493/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/glm-5-1-metered-chat-large-context-9ad82214
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_N8NptaTBVKbFVrkOFa0A7

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 glm-5-1-metered-chat-large-context-9ad82214 -d '<json body>'
```

Example prompt: Ask the GLM-5.1 reasoning model: given this 10,000-character legal document summary, identify all contractual obligations, potential risks, and ambiguous clauses — use up to 2048 tokens in your response.

## When to prefer this

Choose this endpoint when you need a reasoning-tier model (GLM-5.1-FP8) with large-context input support and want metered, pay-per-call pricing without a subscription — ideal for bursty workloads, agent orchestration steps, or long prompts that exceed smaller-context route limits. Prefer over the flat-rate GLM-5.1 sibling when your input is large and you want metered billing. Prefer over other Telnyx models (Gemma, Llama, DeepSeek) when you specifically need GLM-5.1's reasoning capability rather than a smaller or faster model.

## Known failure modes

- Payment failure: insufficient USDC balance or x402 payment rejected — returns 402 Payment Required
- Input too long: messages array exceeds 32 items or content exceeds 200,000 characters — returns 400 validation error
- Invalid model: any model string other than zai-org/GLM-5.1-FP8 is rejected
- max_tokens out of range: values above 8192 or below 1 return a 400 error
- Temperature out of range: values outside 0-2 return a validation error
- More than 16 tools provided: returns a 400 error
- More than 1 completion requested (n>1): rejected as n is fixed to 1

## How this service works

Reasoning-tier chat completions via Telnyx Inference (GLM-5.1-FP8) — 12K-char-per-message input, 2048-token output. OpenAI-compatible. $0.023386 USDC per call. (upto metered — large context)

## Output

An OpenAI-compatible chat completion object containing one assistant message (up to 2048 tokens), optionally including tool_calls if tools were provided. The response includes the generated text, finish reason, token usage counts, and model identifier.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "n": {
   "type": "integer",
   "const": 1,
   "description": "Fixed to one completion per paid call."
  },
  "model": {
   "type": "string",
   "const": "zai-org/GLM-5.1-FP8",
   "description": "Model identifier; fixed to zai-org/GLM-5.1-FP8 on this route."
  },
  "tools": {
   "type": "array",
   "items": {
    "type": "object"
   },
   "maxItems": 16
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant",
       "tool"
      ],
      "type": "string"
     },
     "content": {
      "type": "string",
      "maxLength": 200000
     }
    }
   },
   "maxItems": 32,
   "description": "OpenAI-style chat messages."
  },
  "max_tokens": {
   "type": "integer",
   "maximum": 8192,
   "minimum": 1
  },
  "temperature": {
   "type": "number",
   "maximum": 2,
   "minimum": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/glm-5-1-metered-chat-large-context-9ad82214/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.telnyx.com](https://www.zero.xyz/host/x402.telnyx.com/llms.txt)