# Anthropic Claude via Locus x402

> Anthropic Claude via Locus x402 is a paid API for AI agents from anthropic.x402.paywithlocus.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-11).

Proxies requests to Anthropic's Claude models (chat, vision, tool use, extended thinking) with per-call USDC micropayment settlement via x402.

## Facts

- Endpoint: POST https://anthropic.x402.paywithlocus.com/anthropic/chat?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Success rate: 0% of calls made through Zero
- Activations on Zero: 1
- Tags: x402
- Canonical page: https://www.zero.xyz/c/anthropic-claude-via-locus-x402-90557f46
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_OwkOdH52CeWWKyz55A5vr

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 anthropic-claude-via-locus-x402-90557f46 -d '<json body>'
```

Example prompt: Ask Claude Sonnet to read this base64-encoded screenshot and extract all the line items as JSON — use extended thinking with a 10,000-token budget and limit the output to 4096 tokens.

## When to prefer this

Choose this endpoint when you need Claude specifically (not GPT or Gemini) and want pay-per-call micropayment billing in USDC rather than a monthly subscription or API key management. It is ideal for agentic systems that need Claude's extended thinking, multi-step tool use, or vision capabilities on an unpredictable or low-volume basis where prepaying for a subscription is wasteful. Prefer it over direct Anthropic API access when your agent architecture relies on x402 payment headers for autonomous cost management.

## Known failure modes

- Insufficient USDC balance or failed x402 payment — request rejected before reaching Claude
- Invalid or unsupported model ID — service returns an error listing supported model IDs
- Token limit exceeded — x402 enforces per-model max_tokens caps (128k Opus, 64k Sonnet/Haiku)
- Malformed messages array — missing required role or content fields causes a validation error
- Extended thinking requested on a model that doesn't support it — returns upstream Anthropic error
- Image data too large or wrong media type — base64 image rejected by Anthropic's vision API
- Rate limits from the underlying Anthropic API — transient 529 overload responses

## How this service works

Claude AI models — chat completions, vision, document processing, extended thinking, and tool use.

## Output

Returns a JSON object with a 'data' field containing the full Anthropic API response (content blocks, stop reason, usage), a 'payment' object showing settled and authorized USDC amounts, a 'request' object with a UUID and status URL for tracking, and a 'success' boolean. The nested Anthropic response follows the standard Messages API format with role, content array, and token usage counts.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "type": "string"
  },
  "tools": {
   "type": "array",
   "items": {}
  },
  "top_k": {
   "type": "number"
  },
  "top_p": {
   "type": "number"
  },
  "stream": {
   "type": "boolean"
  },
  "system": {
   "anyOf": [
    {
     "type": "string"
    },
    {
     "type": "array",
     "items": {}
    }
   ]
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role"
    ],
    "properties": {
     "name": {
      "type": "string"
     },
     "role": {
      "type": "string"
     },
     "content": {
      "anyOf": [
       {
        "type": "string"
       },
       {
        "type": "array",
        "items": {
         "type": "object",
         "required": [
          "type"
         ],
         "properties": {
          "text": {
           "type": "string"
          },
          "type": {
           "type": "string"
          },
          "image_url": {
           "type": "object",
           "required": [
            "url"
           ],
           "properties": {
            "url": {
             "type": "string"
            }
           },
           "additionalProperties": true
          }
         },
         "additionalProperties": true
        }
       },
       {
        "type": "null"
       }
      ]
     },
     "tool_calls": {
      "type": "array",
      "items": {
       "type": "object",
       "additionalProperties": true
      }
     },
     "tool_call_id": {
      "type": "string"
     }
    },
    "additionalProperties": true
   }
  },
  "thinking": {
   "type": "object",
   "additionalProperties": true
  },
  "max_tokens": {
   "type": "number"
  },
  "temperature": {
   "type": "number"
  },
  "tool_choice": {
   "type": "object",
   "additionalProperties": true
  },
  "stop_sequences": {
   "type": "array",
   "items": {
    "type": "string"
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {},
  "payment": {
   "scheme": "exact",
   "settledUsdc": "0.001000",
   "authorizedMaxUsdc": "0.001000"
  },
  "request": {
   "id": "00000000-0000-4000-8000-000000000000",
   "statusUrl": "/requests/00000000-0000-4000-8000-000000000000"
  },
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/anthropic-claude-via-locus-x402-90557f46/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from anthropic.x402.paywithlocus.com](https://www.zero.xyz/host/anthropic.x402.paywithlocus.com/llms.txt)