OpenAI-compatible chat completions priced from the request itself

OpenAI-compatible chat completions priced from the request itself: the 402 quotes this exact body, from $0.001, and a buyer on the upto scheme settles the tokens actually used under that quote. Use it when an agent sends large or variable prompts and wants to pay for what it sends, not a flat tier.

Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.

Endpoint

POST https://agent402.tools/v1/metered/chat/completions

Our checks, last 30 days

We never call tools that send, buy, move money or file anything, not even without paying.

Example input (from the provider)

{
  "body": {
    "max_tokens": 5,
    "messages": [
      {
        "content": "Reply with exactly: OK",
        "role": "user"
      }
    ],
    "model": "openai/gpt-4o-mini"
  },
  "bodyType": "json",
  "method": "POST",
  "type": "http"
}

Promised output schema (from the provider)

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "input": {
      "additionalProperties": false,
      "properties": {
        "body": {
          "properties": {
            "cache_control": {
              "description": "Optional - prompt caching preference. Default ON ({type:\"ephemeral\"}, 5-minute TTL): repeated prefixes across your turns are served from the provider cache (same price to you). Send false to disable. ttl:\"1h\" is not offered."
            },
            "max_completion_tokens": {
              "description": "Optional - alias of max_tokens (newer OpenAI SDKs send this).",
              "type": "integer"
            },
            "max_tokens": {
              "description": "Output token cap (clamped to the tier maximum)",
              "type": "number"
            },
            "messages": {
              "description": "OpenAI chat messages: [{role, content}] - text and image_url content blocks supported",
              "type": "array"
            },
            "model": {
              "description": "Model id - OpenRouter form (openai/gpt-4o-mini) or bare OpenAI form (gpt-4o-mini). GET /v1/models lists the allowlist per tier. Optional: omit it and the tier serves its documented default (x402.defaultModel on /v1/models), named back in agent402_default_model; the price does not change",
              "type": "string"
            },
            "reasoning": {
              "description": "Optional - {effort: \"none\"|\"minimal\"|\"low\"|\"medium\"|\"high\"|\"xhigh\"|\"max\", max_tokens?, exclude?, enabled?}. Reasoning tokens count against max_tokens. Omitted: low effort on the budget tiers, the model default on premium. reasoning_effort (string) is accepted as an alias.",
              "type": "object"
            },
            "tools": {
              "description": "Optional - OpenAI function tools {type:\"function\", function:{...}}, or a tool namespace {type:\"namespace\", name, tools:[...]} (flattened into its functions). The pro and premium routes also accept the bounded server tools openrouter:web_search, openrouter:web_fetch and openrouter:datetime with server-owned limits (GET /v1/models lists them); stop_server_tools_when and max_tool_calls are refused. A request with a server tool is never served from the prompt cache.",
              "type": "array"
            },
            "zdr": {
              "description": "Optional - true routes only to zero-data-retention providers (OpenRouter provider.zdr); the only provider preference a caller may set.",
              "type": "boolean"
            }
          },
          "required": [
            "messages"
          ]
        },
        "bodyType": {
          "enum": [
            "json",
            "form-data",
            "text"
          ],
          "type": "string"
        },
        "method": {
          "enum": [
            "POST"
          ],
          "type": "string"
        },
        "type": {
          "const": "http",
          "type": "string"
        }
      },
      "required": [
        "type",
        "method",
        "bodyType",
        "body"
      ],
      "type": "object"
    },
    "output": {
      "properties": {
        "example": {
          "properties": {
            "choices": {
              "items": {
                "type": "object"
              },
              "type": "array"
            },
            "created": {
              "type": "integer"
            },
            "id": {
              "type": "string"
            },
            "model": {
              "type": "string"
            },
            "object": {
              "type": "string"
            },
            "usage": {
              "properties": {
                "completion_tokens": {
                  "type": "integer"
                },
                "prompt_tokens": {
                  "type": "integer"
                },
                "total_tokens": {
                  "type": "integer"
                }
              },
              "type": "object"
            }
          },
          "required": [
            "id",
            "object",
            "created",
            "model",
            "choices",
            "usage"
          ],
          "type": "object"
        },
        "type": {
          "type": "string"
        }
      },
      "required": [
        "type"
      ],
      "type": "object"
    }
  },
  "required": [
    "input"
  ],
  "type": "object"
}

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