# Clink Lithium Vault – Keyless Claude API (LLM Chat)

> Clink Lithium Vault – Keyless Claude API (LLM Chat) is a paid API for AI agents from clink-lithium-vault.fly.dev, paid per call via x402, $0.25/call, status unknown (last checked 2026-10-10).

Proxies Anthropic Claude (Haiku 4.5, Sonnet 5, Opus 5) chat completions with tool-calling support, billed per token via x402 micropayments — no API key required.

## Facts

- Endpoint: POST https://clink-lithium-vault.fly.dev/llm/chat?utm_source=zero.xyz
- Price: $0.25/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/clink-lithium-vault-keyless-claude-api-llm-chat-a6054a23
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0J9G_C3ne59F1gjdHTdgN

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 clink-lithium-vault-keyless-claude-api-llm-chat-a6054a23 -d '<json body>'
```

Example prompt: Ask Claude Sonnet 5 — no API key needed — to write a 3-paragraph summary of quantum computing for a general audience, using up to 512 tokens.

## When to prefer this

Choose this endpoint when an AI agent needs Claude inference (including tool calling and system prompts) without managing Anthropic API credentials or subscriptions. Ideal for ephemeral agent tasks, multi-agent pipelines billed per call, or situations where setting up an Anthropic account is impractical. The $0.25-per-call cap makes it predictable for budget-conscious agents. Prefer a direct Anthropic API key if you need bulk throughput, fine-grained rate limits, or sub-list pricing.

## Known failure modes

- Payment not included or insufficient — x402 payment required before response is returned
- Model enum not recognized — must use exact values like 'sonnet', 'claude-sonnet-5', 'haiku', etc.
- messages array missing or first role is not 'user' — API rejects malformed message arrays
- max_tokens out of range (must be 1–4096) — defaults to 1024 if omitted
- Anthropic upstream timeout or rate limit — proxy may return 5xx error
- Call cost exceeds $0.25 cap — very long conversations may be refused or truncated

## How this service works

Claude API for AI agents, pay per token, no API key or account - POST an Anthropic Messages request (messages, system, tools, tool_choice, thinking) and get the full response back. Claude Opus 5, Sonnet 5, Haiku 4.5. Tool calling / function calling supported. Billed on actual usage at list price + 25%, capped at $0.25 per call (x402 upto scheme). LLM inference, chat completions, keyless Claude, Anthropic proxy. Free price sheet: /llm/models.

## Output

Returns a full Anthropic Messages API response object: content array with text or tool_use blocks, stop_reason (e.g. end_turn or tool_use), and usage object containing input_tokens and output_tokens.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "haiku",
    "sonnet",
    "opus",
    "fable",
    "claude-haiku-4-5",
    "claude-sonnet-5-5",
    "claude-opus-5-5",
    "claude-fable-5-1"
   ],
   "type": "string"
  },
  "tools": {
   "type": "array",
   "description": "Optional tool definitions (Anthropic tool-use schema)"
  },
  "system": {
   "type": "string",
   "description": "Optional system prompt"
  },
  "messages": {
   "type": "array",
   "description": "Anthropic Messages API messages array; first role must be user"
  },
  "max_tokens": {
   "type": "integer",
   "description": "1-4096, default 1024"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "usage": {
   "input_tokens": 12,
   "output_tokens": 8
  },
  "content": [
   {
    "text": "Hi there, nice to meet you!",
    "type": "text"
   }
  ],
  "stop_reason": "end_turn"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/clink-lithium-vault-keyless-claude-api-llm-chat-a6054a23/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from clink-lithium-vault.fly.dev](https://www.zero.xyz/host/clink-lithium-vault.fly.dev/llms.txt)