# GPT55 x402 Gateway MCP Server

**Canonical:** https://apis.io/apis/558686-xyz/gpt55-mcp-server/  
**Provider:** gpt55-token-gateway — https://apis.io/providers/558686-xyz/  
**Base URL:** https://gpt55.558686.xyz/mcp  
**Documentation:** https://gpt55.558686.xyz/projects/558686/install

GPT55 x402 Gateway MCP Server is one of 5 APIs that [gpt55-token-gateway](https://apis.io/providers/558686-xyz/) publishes on the [APIs.io](https://apis.io/) network. Tagged areas include MCP, x402, and AI Agents. The published artifact set on APIs.io includes API documentation.

Remote Model Context Protocol server at https://gpt55.558686.xyz/mcp (Streamable HTTP; a GET returns the server.json-shaped manifest and /mcp/sse streams the discovery config). Probed anonymously on 2026-09-20: initialize answered protocolVersion 2025-06-18, serverInfo {gpt55-x402-gateway, "GPT-5.5 x402 Agent Payment Control Plane", 2026.06.21}, capabilities tools + resources; tools/list returned 218 tools, each with a JSON Schema inputSchema and MCP annotations; resources/list returned 14 JSON resources (x402 discovery, live prices, pricing, buyer guide, agent card, openapi). The server's own instructions state that it is a facade: a tool call returns the direct HTTP endpoint, the x402 payment requirements and an example payload, and the caller must execute that HTTP endpoint with x402 Base USDC payment or a private Bearer key - "this MCP facade does not bypass payment". Registered-shape server.json at /server.json and /.well-known/mcp.json (name gpt55-model-gateway, version 2026.07.01-split) and a SEP-1649 server card at /.well-known/mcp/server-card.json (xyz.558686.gpt55/token-gateway); no entry was found in the official MCP registry and the install guide says no marketplace submission has been made.

## Machine-readable artifacts (4)

- **MCPServer** — https://raw.githubusercontent.com/api-evangelist/558686-xyz/refs/heads/main/mcp/558686-xyz-mcp.yml
- **MCPServer** — https://gpt55.558686.xyz/mcp
- **ToolCrosswalk** — https://raw.githubusercontent.com/api-evangelist/558686-xyz/refs/heads/main/mcp/558686-xyz-tool-crosswalk.yml
- **Documentation** — https://gpt55.558686.xyz/llms-install.md

## Other gpt55-token-gateway APIs (4)

- [GPT55 Model Gateway API](https://apis.io/apis/558686-xyz/gpt55-model-gateway-api/)
- [GPT-5.5 Utility Tools for API.market](https://apis.io/apis/558686-xyz/gpt55-utility-tools-api-market/)
- [GPT55 Model Gateway A2A Agent](https://apis.io/apis/558686-xyz/gpt55-a2a-agent/)
- [Sub2API OpenAI-compatible API](https://apis.io/apis/558686-xyz/sub2api-openai-compatible-api/)

## Tags

MCP, x402, AI Agents

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/558686-xyz/gpt55-mcp-server/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/558686-xyz/.