"id",
            "timestamp",
            "parentId",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "const": true
            },
            "type": {
              "type": "string",
              "const": "session.idle"
            },
            "data": {
              "type": "object",
              "properties": {
                "backgroundTasks": {
                  "type": "object",
                  "properties": {
                    "agents": {
                      "type": "array",
                      "items": {
                        "type": "object",
                        "properties": {
                          "agentId": {
                            "type": "string",
                            "description": "Unique identifier of the background agent"
                          },
                          "agentType": {
                            "type": "string",
                            "description": "Type of the background agent"
                          },
                          "description": {
                            "type": "string",
                            "description": "Human-readable description of the agent task"
                          }
                        },
                        "required": [
                          "agentId",
                          "agentType"
                        ],
                        "additionalProperties": false,
                        "description": "A background agent task"
                      },
                      "description": "Currently running background agents"
                    },
                    "shells": {
                      "type": "array",
                      "items": {
                        "type": "object",
                        "properties": {
                          "shellId": {
                            "type": "string",
                            "description": "Unique identifier of the background shell"
                          },
                          "description": {
                            "type": "string",
                            "description": "Human-readable description of the shell command"
                          }
                        },
                        "required": [
                          "shellId"
                        ],
                        "additionalProperties": false,
                        "description": "A background shell command"
                      },
                      "description": "Currently running background shell commands"
                    }
                  },
                  "required": [
                    "agents",
                    "shells"
                  ],
                  "additionalProperties": false,
                  "description": "Background tasks still running when the agent became idle"
                }
              },
              "additionalProperties": false,
              "description": "Payload indicating the agent is idle; includes any background tasks still in flight"
            }
          },
          "required": [
            "id",
            "timestamp",
            "parentId",
            "ephemeral",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "const": true
            },
            "type": {
              "type": "string",
              "const": "session.title_changed"
            },
            "data": {
              "type": "object",
              "properties": {
                "title": {
                  "type": "string",
                  "description": "The new display title for the session"
                }
              },
              "required": [
                "title"
              ],
              "additionalProperties": false,
              "description": "Session title change payload containing the new display title"
            }
          },
          "required": [
            "id",
            "timestamp",
            "parentId",
            "ephemeral",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "description": "When true, the event is transient and not persisted to the session event log on disk"
            },
            "type": {
              "type": "string",
              "const": "session.info"
            },
            "data": {
              "type": "object",
              "properties": {
                "infoType": {
                  "type": "string",
                  "description": "Category of informational message (e.g., \"notification\", \"timing\", \"context_window\", \"mcp\", \"snapshot\", \"configuration\", \"authentication\", \"model\")"
                },
                "message": {
                  "type": "string",
                  "description": "Human-readable informational message for display in the timeline"
                }
              },
              "required": [
                "infoType",
                "message"
              ],
              "additionalProperties": false,
              "description": "Informational message for timeline display with categorization"
            }
          },
          "required": [
            "id",
            "timestamp",
            "parentId",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "description": "When true, the event is transient and not persisted to the session event log on disk"
            },
            "type": {
              "type": "string",
              "const": "session.warning"
            },
            "data": {
              "type": "object",
              "properties": {
                "warningType": {
                  "type": "string",
                  "description": "Category of warning (e.g., \"subscription\", \"policy\", \"mcp\")"
                },
                "message": {
                  "type": "string",
                  "description": "Human-readable warning message for display in the timeline"
                }
              },
              "required": [
                "warningType",
                "message"
              ],
              "additionalProperties": false,
              "description": "Warning message for timeline display with categorization"
            }
          },
          "required": [
            "id",
            "timestamp",
            "parentId",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "description": "When true, the event is transient and not persisted to the session event log on disk"
            },
            "type": {
              "type": "string",
              "const": "session.model_change"
            },
            "data": {
              "type": "object",
              "properties": {
                "previousModel": {
                  "type": "string",
                  "description": "Model that was previously selected, if any"
                },
                "newModel": {
                  "type": "string",
                  "description": "Newly selected model identifier"
                },
                "previousReasoningEffort": {
                  "type": "string",
                  "description": "Reasoning effort level before the model change, if applicable"
                },
                "reasoningEffort": {
                  "type": "string",
                  "description": "Reasoning effort level after the model change, if applicable"
                }
              },
              "required": [
                "newModel"
              ],
              "additionalProperties": false,
              "description": "Model change details including previous and new model identifiers"
            }
          },
          "required": [
            "id",
            "timestamp",
            "parentId",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "description": "When true, the event is transient and not persisted to the session event log on disk"
            },
            "type": {
              "type": "string",
              "const": "session.mode_changed"
            },
            "data": {
              "type": "object",
              "properties": {
                "previousMode": {
                  "type": "string",
                  "description": "Agent mode before the change (e.g., \"interactive\", \"plan\", \"autopilot\")"
                },
                "newMode": {
                  "type": "string",
                  "description": "Agent mode after the change (e.g., \"interactive\", \"plan\", \"autopilot\")"
                }
              },
              "required": [
                "previousMode",
                "newMode"
              ],
              "additionalProperties": false,
              "description": "Agent mode change details including previous and new modes"
            }
          },
          "required": [
            "id",
            "timestamp",
            "parentId",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "description": "When true, the event is transient and not persisted to the session event log on disk"
            },
            "type": {
              "type": "string",
              "const": "session.plan_changed"
            },
            "data": {
              "type": "object",
              "properties": {
                "operation": {
                  "type": "string",
                  "enum": [
                    "create",
                    "update",
                    "delete"
                  ],
                  "description": "The type of operation performed on the plan file"
                }
              },
              "required": [
                "operation"
              ],
              "additionalProperties": false,
              "description": "Plan file operation details indicating what changed"
            }
          },
          "required": [
            "id",
            "timestamp",
            "parentId",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "description": "When true, the event is transient and not persisted to the session event log on disk"
            },
            "type": {
              "type": "string",
              "const": "session.workspace_file_changed"
            },
            "data": {
              "type": "object",
              "properties": {
                "path": {
                  "type": "string",
                  "description": "Relative path within the session workspace files directory"
                },
                "operation": {
                  "type": "string",
                  "enum": [
                    "create",
                    "update"
                  ],
                  "description": "Whether the file was newly created or updated"
                }
              },
              "required": [
                "path",
                "operation"
              ],
              "additionalProperties": false,
              "description": "Workspace file change details including path and operation type"
            }
          },
          "required": [
            "id",
            "timestamp",
            "parentId",
            "type",
            "data"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "id": {
              "type": "string",
              "format": "uuid",
              "description": "Unique event identifier (UUID v4), generated when the event is emitted"
            },
            "timestamp": {
              "type": "string",
              "format": "date-time",
              "description": "ISO 8601 timestamp when the event was created"
            },
            "parentId": {
              "anyOf": [
                {
                  "type": "string",
                  "format": "uuid"
                },
                {
                  "type": "null"
                }
              ],
              "description": "ID of the chronologically preceding event in the session, forming a linked chain. Null for the first event."
            },
            "ephemeral": {
              "type": "boolean",
              "description": "When true, the event is transient and not persisted to the session event log on disk"
            },
            "type": {
              "type": "string",
              "const": "session.import_legacy"
            },
            "data": {
              "type": "object",
              "properties": {
                "legacySession": {
                  "type": "object",
                  "properties": {
                    "sessionId": {
                      "type": "string"
                    },
                    "startTime": {
                      "type": "string",
                      "format": "date-time"
                    },
                    "chatMessages": {
                      "type": "array",
                      "items": {
                        "anyOf": [
                          {
                            "type": "object",
                            "properties": {
                              "content": {
                                "anyOf": [
                                  {
                                    "type": "string"
                                  },
                                  {
                                    "type": "array",
                                    "items": {
                                      "type": "object",
                                      "properties": {
                                        "type": {
                                          "type": "string",
                                          "const": "text"
                                        },
                                        "text": {
                                          "type": "string"
                                        }
                                      },
                                      "required": [
                                        "type",
                                        "text"
                                      ],
                                      "additionalProperties": false
                                    }
                                  }
                                ]
                              },
                              "role": {
                                "type": "string",
                                "const": "developer"
                              },
                              "name": {
                                "type": "string"
                              }
                            },
                            "required": [
                              "content",
                              "role"
                            ],
                            "additionalProperties": false
                          },
                          {
                            "type": "object",
                            "properties": {
                              "content": {
                                "anyOf": [
                                  {
                                    "type": "string"
                                  },
                                  {
                                    "type": "array",
                                    "items": {
                                      "type": "object",
                                      "properties": {
                                        "type": {
                                          "type": "string",
                                          "const": "text"
                                        },
                                        "text": {
                                          "type": "string"
                                        }
                                      },
                                      "required": [
                                        "type",
                                        "text"
                                      ],
                                      "additionalProperties": false
                                    }
                                  }
                                ]
                              },
                              "role": {
                                "type": "string",
                                "const": "system"
                              },
                              "name": {
                                "type": "string"
                              }
                            },
                            "required": [
                              "content",
                              "role"
                            ],
                            "addit