{
  "openapi": "3.1.0",
  "info": {
    "title": "Hermes Agent Gateway API",
    "description": "Production Reverse Proxy API for Hermes Agent Gateway.\nSecured behind a timing-safe Auth Key barrier and designed for integration with\nexternal chat applications, mobile frontends, and autonomous AI agents.\n",
    "version": "1.0.0"
  },
  "servers": [
    {
      "url": "https://{cloudflare_domain}:{port}",
      "description": "Public Cloudflare Reverse Proxy (HTTPS Port Forwarding)",
      "variables": {
        "cloudflare_domain": {
          "default": "hermes.yourdomain.com",
          "description": "Cloudflare proxied hostname"
        },
        "port": {
          "default": "8443",
          "description": "Forwarded WAN port (e.g. 8443 or 443)"
        }
      }
    },
    {
      "url": "http://localhost:8643",
      "description": "Local Direct Reverse Proxy"
    }
  ],
  "security": [
    {
      "BearerAuth": []
    },
    {
      "ApiKeyAuth": []
    }
  ],
  "components": {
    "securitySchemes": {
      "BearerAuth": {
        "type": "http",
        "scheme": "bearer",
        "description": "Supply proxy auth key via Authorization: Bearer <AUTH_KEY>"
      },
      "ApiKeyAuth": {
        "type": "apiKey",
        "in": "header",
        "name": "X-API-Key",
        "description": "Supply proxy auth key via X-API-Key: <AUTH_KEY>"
      }
    },
    "schemas": {
      "ChatMessage": {
        "type": "object",
        "required": [
          "role",
          "content"
        ],
        "properties": {
          "role": {
            "type": "string",
            "enum": [
              "system",
              "user",
              "assistant",
              "tool"
            ],
            "description": "Message author role"
          },
          "content": {
            "type": "string",
            "description": "Message body text"
          },
          "name": {
            "type": "string",
            "description": "Optional author or tool name"
          }
        }
      },
      "ChatCompletionRequest": {
        "type": "object",
        "required": [
          "messages"
        ],
        "properties": {
          "model": {
            "type": "string",
            "default": "auto",
            "description": "Model identifier or alias (defaults to gateway configured active model)"
          },
          "messages": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/ChatMessage"
            }
          },
          "stream": {
            "type": "boolean",
            "default": false,
            "description": "Enable Server-Sent Events (SSE) streaming"
          },
          "temperature": {
            "type": "number",
            "default": 0.7
          },
          "max_tokens": {
            "type": "integer",
            "description": "Optional completion token limit"
          }
        }
      },
      "ChatCompletionResponse": {
        "type": "object",
        "properties": {
          "id": {
            "type": "string"
          },
          "object": {
            "type": "string",
            "example": "chat.completion"
          },
          "created": {
            "type": "integer"
          },
          "model": {
            "type": "string"
          },
          "choices": {
            "type": "array",
            "items": {
              "type": "object",
              "properties": {
                "index": {
                  "type": "integer"
                },
                "message": {
                  "$ref": "#/components/schemas/ChatMessage"
                },
                "finish_reason": {
                  "type": "string",
                  "example": "stop"
                }
              }
            }
          },
          "usage": {
            "type": "object",
            "properties": {
              "prompt_tokens": {
                "type": "integer"
              },
              "completion_tokens": {
                "type": "integer"
              },
              "total_tokens": {
                "type": "integer"
              }
            }
          }
        }
      },
      "SessionCreateRequest": {
        "type": "object",
        "properties": {
          "title": {
            "type": "string",
            "description": "Optional descriptive session title"
          },
          "model": {
            "type": "string",
            "description": "Model override for this session"
          }
        }
      },
      "SessionChatStreamRequest": {
        "type": "object",
        "required": [
          "message"
        ],
        "properties": {
          "message": {
            "type": "string",
            "description": "User prompt or message to send to Hermes"
          },
          "model": {
            "type": "string",
            "description": "Optional model override"
          }
        }
      },
      "ErrorResponse": {
        "type": "object",
        "properties": {
          "error": {
            "type": "object",
            "properties": {
              "message": {
                "type": "string"
              },
              "type": {
                "type": "string"
              },
              "code": {
                "type": "integer"
              }
            }
          }
        }
      }
    }
  },
  "paths": {
    "/health": {
      "get": {
        "summary": "Health Check",
        "description": "Returns liveness status of the reverse proxy (publicly accessible).",
        "security": [],
        "responses": {
          "200": {
            "description": "Proxy healthy",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "status": {
                      "type": "string",
                      "example": "ok"
                    },
                    "proxy": {
                      "type": "string",
                      "example": "nginx"
                    },
                    "port": {
                      "type": "integer",
                      "example": 8643
                    }
                  }
                }
              }
            }
          }
        }
      }
    },
    "/v1/chat/completions": {
      "post": {
        "summary": "OpenAI-Compatible Chat Completions",
        "description": "Primary endpoint for chat app integration. Compatible with the official OpenAI SDK in Python, TypeScript, Go, etc. When stream is true, responses are streamed as standard text/event-stream Server-Sent Events.\n",
        "requestBody": {
          "required": true,
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/ChatCompletionRequest"
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "Successful completion (non-streaming JSON or streaming SSE)",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/ChatCompletionResponse"
                }
              },
              "text/event-stream": {
                "schema": {
                  "type": "string",
                  "description": "Chunked SSE stream (data: {\"choices\":[{\"delta\":{\"content\":\"...\"}}]})"
                }
              }
            }
          },
          "401": {
            "description": "Missing or invalid proxy auth key",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/ErrorResponse"
                }
              }
            }
          }
        }
      }
    },
    "/v1/models": {
      "get": {
        "summary": "List Models",
        "description": "Returns list of available models and aliases configured in Hermes Gateway.",
        "responses": {
          "200": {
            "description": "List of models",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "object": {
                      "type": "string",
                      "example": "list"
                    },
                    "data": {
                      "type": "array",
                      "items": {
                        "type": "object",
                        "properties": {
                          "id": {
                            "type": "string"
                          },
                          "object": {
                            "type": "string",
                            "example": "model"
                          }
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    },
    "/api/sessions": {
      "get": {
        "summary": "List Conversation Sessions",
        "description": "Retrieves ongoing and archived conversation sessions.",
        "responses": {
          "200": {
            "description": "Array of session summaries"
          }
        }
      },
      "post": {
        "summary": "Create New Session",
        "description": "Creates an isolated conversation session in Hermes Gateway.",
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/SessionCreateRequest"
              }
            }
          }
        },
        "responses": {
          "201": {
            "description": "Session created"
          }
        }
      }
    },
    "/api/sessions/{session_id}/messages": {
      "get": {
        "summary": "Get Session Message History",
        "description": "Returns all previous turns, tool executions, and assistant responses for a session.",
        "parameters": [
          {
            "name": "session_id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "string"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "Conversation history"
          }
        }
      }
    },
    "/api/sessions/{session_id}/chat/stream": {
      "post": {
        "summary": "Native Hermes Chat Stream",
        "description": "Dispatches a user turn in an existing session and streams raw assistant output, including live tool calls and reasoning events, via Server-Sent Events.\n",
        "parameters": [
          {
            "name": "session_id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "string"
            }
          }
        ],
        "requestBody": {
          "required": true,
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/SessionChatStreamRequest"
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "SSE event stream",
            "content": {
              "text/event-stream": {
                "schema": {
                  "type": "string"
                }
              }
            }
          }
        }
      }
    }
  }
}