diff --git a/openapi/openapiv2.json b/openapi/openapiv2.json
index 388c769e..2f7ba2a9 100644
--- a/openapi/openapiv2.json
+++ b/openapi/openapiv2.json
@@ -6847,42 +6847,6 @@
       },
       "description": "UpdateWorkflowOptions represents updating workflow execution options after a workflow reset.\nKeep the parameters in sync with temporal.api.workflowservice.v1.UpdateWorkflowExecutionOptionsRequest."
     },
-    "StartOperationResponseAsync": {
-      "type": "object",
-      "properties": {
-        "operationId": {
-          "type": "string",
-          "description": "Deprecated: Renamed to operation_token."
-        },
-        "links": {
-          "type": "array",
-          "items": {
-            "type": "object",
-            "$ref": "#/definitions/apinexusv1Link"
-          }
-        },
-        "operationToken": {
-          "type": "string"
-        }
-      },
-      "description": "The operation will complete asynchronously.\nThe returned ID can be used to reference this operation."
-    },
-    "StartOperationResponseSync": {
-      "type": "object",
-      "properties": {
-        "payload": {
-          "$ref": "#/definitions/v1Payload"
-        },
-        "links": {
-          "type": "array",
-          "items": {
-            "type": "object",
-            "$ref": "#/definitions/apinexusv1Link"
-          }
-        }
-      },
-      "description": "An operation completed successfully."
-    },
     "UpdateWorkerBuildIdCompatibilityRequestAddNewCompatibleVersion": {
       "type": "object",
       "properties": {
@@ -8294,6 +8258,12 @@
         },
         "cancelOperation": {
           "$ref": "#/definitions/v1CancelOperationRequest"
+        },
+        "getOperationInfo": {
+          "$ref": "#/definitions/v1GetOperationInfoRequest"
+        },
+        "getOperationResult": {
+          "$ref": "#/definitions/v1GetOperationResultRequest"
         }
       },
       "description": "A Nexus request."
@@ -8306,6 +8276,12 @@
         },
         "cancelOperation": {
           "$ref": "#/definitions/v1CancelOperationResponse"
+        },
+        "getOperationInfo": {
+          "$ref": "#/definitions/v1GetOperationInfoResponse"
+        },
+        "getOperationResult": {
+          "$ref": "#/definitions/v1GetOperationResultResponse"
         }
       },
       "description": "A response indicating that the handler has successfully processed a request."
@@ -9090,6 +9066,10 @@
       ],
       "default": "CANCEL_EXTERNAL_WORKFLOW_EXECUTION_FAILED_CAUSE_UNSPECIFIED"
     },
+    "v1CancelNexusOperationResponse": {
+      "type": "object",
+      "description": "If this response is returned, the cancelation request was successfully processed by a Handler.\nThe operation may ignore the cancelation request and end up in any terminal state."
+    },
     "v1CancelOperationRequest": {
       "type": "object",
       "properties": {
@@ -10299,6 +10279,148 @@
         }
       }
     },
+    "v1GetNexusOperationInfoResponse": {
+      "type": "object",
+      "properties": {
+        "info": {
+          "$ref": "#/definitions/v1OperationInfo"
+        }
+      }
+    },
+    "v1GetNexusOperationResultResponse": {
+      "type": "object",
+      "properties": {
+        "completeSuccess": {
+          "$ref": "#/definitions/v1GetNexusOperationResultResponseComplete"
+        },
+        "operationError": {
+          "$ref": "#/definitions/v1UnsuccessfulOperationError",
+          "description": "The operation completed unsuccessfully (failed or canceled)."
+        },
+        "stillRunning": {
+          "$ref": "#/definitions/v1GetNexusOperationResultResponseStillRunning",
+          "description": "The operation is still running, When waiting for completion, the caller may re-issue this request to start a\nnew long poll."
+        },
+        "timeout": {
+          "$ref": "#/definitions/v1GetNexusOperationResultResponseTimeout",
+          "title": "The server gave up waiting for operation completion. The request may be retried by the caller.\nTODO: does the SDK need to return this or is this a server only result?"
+        }
+      }
+    },
+    "v1GetNexusOperationResultResponseComplete": {
+      "type": "object",
+      "properties": {
+        "payload": {
+          "$ref": "#/definitions/v1Payload"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "$ref": "#/definitions/apinexusv1Link"
+          }
+        }
+      },
+      "description": "The operation completed successfully."
+    },
+    "v1GetNexusOperationResultResponseStillRunning": {
+      "type": "object"
+    },
+    "v1GetNexusOperationResultResponseTimeout": {
+      "type": "object"
+    },
+    "v1GetOperationInfoRequest": {
+      "type": "object",
+      "properties": {
+        "service": {
+          "type": "string",
+          "description": "Service name."
+        },
+        "operation": {
+          "type": "string",
+          "description": "Operation name."
+        },
+        "operationToken": {
+          "type": "string",
+          "description": "Operation token as originally generated by a Handler."
+        }
+      },
+      "description": "A request to cancel an operation.\n"
+    },
+    "v1GetOperationInfoResponse": {
+      "type": "object",
+      "properties": {
+        "info": {
+          "$ref": "#/definitions/v1OperationInfo"
+        }
+      },
+      "description": "Response variant for GetOperationInfoRequest."
+    },
+    "v1GetOperationResultRequest": {
+      "type": "object",
+      "properties": {
+        "service": {
+          "type": "string",
+          "description": "Service name."
+        },
+        "operation": {
+          "type": "string",
+          "description": "Operation name."
+        },
+        "operationToken": {
+          "type": "string",
+          "description": "Operation token as originally generated by a Handler."
+        },
+        "wait": {
+          "type": "string",
+          "description": "If set and non-zero, reflects the duration the caller has indicated that it wants to wait for operation\ncompletion, turning the request into a long poll."
+        }
+      },
+      "description": "A request to cancel an operation.\n"
+    },
+    "v1GetOperationResultResponse": {
+      "type": "object",
+      "properties": {
+        "completeSuccess": {
+          "$ref": "#/definitions/v1GetOperationResultResponseComplete"
+        },
+        "operationError": {
+          "$ref": "#/definitions/v1UnsuccessfulOperationError",
+          "description": "The operation completed unsuccessfully (failed or canceled)."
+        },
+        "stillRunning": {
+          "$ref": "#/definitions/v1GetOperationResultResponseStillRunning",
+          "description": "The operation is still running, When waiting for completion, the caller may re-issue this request to start a\nnew long poll."
+        },
+        "timeout": {
+          "$ref": "#/definitions/v1GetOperationResultResponseTimeout",
+          "title": "The server gave up waiting for operation completion. The request may be retried by the caller.\nTODO: does the SDK need to return this or is this a server only result?"
+        }
+      },
+      "description": "Response variant for GetOperationResultRequest."
+    },
+    "v1GetOperationResultResponseComplete": {
+      "type": "object",
+      "properties": {
+        "payload": {
+          "$ref": "#/definitions/v1Payload"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "$ref": "#/definitions/apinexusv1Link"
+          }
+        }
+      },
+      "description": "The operation completed successfully."
+    },
+    "v1GetOperationResultResponseStillRunning": {
+      "type": "object"
+    },
+    "v1GetOperationResultResponseTimeout": {
+      "type": "object"
+    },
     "v1GetSearchAttributesResponse": {
       "type": "object",
       "properties": {
@@ -11635,6 +11757,19 @@
       },
       "description": "When StartWorkflowExecution uses the conflict policy WORKFLOW_ID_CONFLICT_POLICY_USE_EXISTING and\nthere is already an existing running workflow, OnConflictOptions defines actions to be taken on\nthe existing running workflow. In this case, it will create a WorkflowExecutionOptionsUpdatedEvent\nhistory event in the running workflow with the changes requested in this object."
     },
+    "v1OperationInfo": {
+      "type": "object",
+      "properties": {
+        "token": {
+          "type": "string",
+          "description": "Operation token as originally generated by a Handler."
+        },
+        "state": {
+          "type": "string"
+        }
+      },
+      "description": "See https://github.com/nexus-rpc/api/blob/main/SPEC.md#operationinfo."
+    },
     "v1Outcome": {
       "type": "object",
       "properties": {
@@ -13662,6 +13797,53 @@
         }
       }
     },
+    "v1StartNexusOperationResponse": {
+      "type": "object",
+      "properties": {
+        "syncSuccess": {
+          "$ref": "#/definitions/v1StartNexusOperationResponseSync"
+        },
+        "asyncSuccess": {
+          "$ref": "#/definitions/v1StartNexusOperationResponseAsync"
+        },
+        "operationError": {
+          "$ref": "#/definitions/v1UnsuccessfulOperationError",
+          "description": "The operation completed unsuccessfully (failed or canceled)."
+        }
+      }
+    },
+    "v1StartNexusOperationResponseAsync": {
+      "type": "object",
+      "properties": {
+        "operationToken": {
+          "type": "string"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "$ref": "#/definitions/apinexusv1Link"
+          }
+        }
+      },
+      "description": "The operation will complete asynchronously.\nThe returned token can be used to reference this operation."
+    },
+    "v1StartNexusOperationResponseSync": {
+      "type": "object",
+      "properties": {
+        "payload": {
+          "$ref": "#/definitions/v1Payload"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "$ref": "#/definitions/apinexusv1Link"
+          }
+        }
+      },
+      "description": "An operation completed successfully."
+    },
     "v1StartOperationRequest": {
       "type": "object",
       "properties": {
@@ -13707,10 +13889,10 @@
       "type": "object",
       "properties": {
         "syncSuccess": {
-          "$ref": "#/definitions/StartOperationResponseSync"
+          "$ref": "#/definitions/v1StartOperationResponseSync"
         },
         "asyncSuccess": {
-          "$ref": "#/definitions/StartOperationResponseAsync"
+          "$ref": "#/definitions/v1StartOperationResponseAsync"
         },
         "operationError": {
           "$ref": "#/definitions/v1UnsuccessfulOperationError",
@@ -13719,6 +13901,42 @@
       },
       "description": "Response variant for StartOperationRequest."
     },
+    "v1StartOperationResponseAsync": {
+      "type": "object",
+      "properties": {
+        "operationId": {
+          "type": "string",
+          "description": "Deprecated: Renamed to operation_token."
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "$ref": "#/definitions/apinexusv1Link"
+          }
+        },
+        "operationToken": {
+          "type": "string"
+        }
+      },
+      "description": "The operation will complete asynchronously.\nThe returned token can be used to reference this operation."
+    },
+    "v1StartOperationResponseSync": {
+      "type": "object",
+      "properties": {
+        "payload": {
+          "$ref": "#/definitions/v1Payload"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "$ref": "#/definitions/apinexusv1Link"
+          }
+        }
+      },
+      "description": "An operation completed successfully."
+    },
     "v1StartTimeFilter": {
       "type": "object",
       "properties": {
diff --git a/temporal/api/nexus/v1/message.proto b/temporal/api/nexus/v1/message.proto
index 6a6eb564..23435ac0 100644
--- a/temporal/api/nexus/v1/message.proto
+++ b/temporal/api/nexus/v1/message.proto
@@ -10,6 +10,7 @@ option ruby_package = "Temporalio::Api::Nexus::V1";
 option csharp_namespace = "Temporalio.Api.Nexus.V1";
 
 import "google/protobuf/timestamp.proto";
+import "google/protobuf/duration.proto";
 import "temporal/api/common/v1/message.proto";
 import "temporal/api/enums/v1/nexus.proto";
 
@@ -42,6 +43,13 @@ message Link {
     string type = 2;
 }
 
+// See https://github.com/nexus-rpc/api/blob/main/SPEC.md#operationinfo.
+message OperationInfo {
+    // Operation token as originally generated by a Handler.
+    string token = 1;
+    string state = 2;
+}
+
 // A request to start an operation.
 message StartOperationRequest {
     // Name of service to start the operation in.
@@ -75,6 +83,36 @@ message CancelOperationRequest {
     string operation_token = 4;
 }
 
+// A request to cancel an operation.
+//
+// (-- api-linter: core::0131::request-name-required=disabled --)
+// (-- api-linter: core::0131::request-unknown-fields=disabled --)
+message GetOperationInfoRequest {
+    // Service name.
+    string service = 1;
+    // Operation name.
+    string operation = 2;
+    // Operation token as originally generated by a Handler.
+    string operation_token = 3;
+}
+
+// A request to cancel an operation.
+//
+// (-- api-linter: core::0131::request-name-required=disabled --)
+// (-- api-linter: core::0131::request-unknown-fields=disabled --)
+message GetOperationResultRequest {
+    // Service name.
+    string service = 1;
+    // Operation name.
+    string operation = 2;
+    // Operation token as originally generated by a Handler.
+    string operation_token = 3;
+
+    // If set and non-zero, reflects the duration the caller has indicated that it wants to wait for operation
+    // completion, turning the request into a long poll.
+    google.protobuf.Duration wait = 4;
+}
+
 // A Nexus request.
 message Request {
     // Headers extracted from the original request in the Temporal frontend.
@@ -89,6 +127,8 @@ message Request {
     oneof variant {
         StartOperationRequest start_operation = 3;
         CancelOperationRequest cancel_operation = 4;
+        GetOperationInfoRequest get_operation_info = 5;
+        GetOperationResultRequest get_operation_result = 6;
     }
 }
 
@@ -101,7 +141,7 @@ message StartOperationResponse {
     }
 
     // The operation will complete asynchronously.
-    // The returned ID can be used to reference this operation.
+    // The returned token can be used to reference this operation.
     message Async {
         // Deprecated: Renamed to operation_token.
         string operation_id = 1;
@@ -121,12 +161,46 @@ message StartOperationResponse {
 message CancelOperationResponse {
 }
 
+// Response variant for GetOperationInfoRequest.
+message GetOperationInfoResponse {
+    OperationInfo info = 1;
+}
+
+// Response variant for GetOperationResultRequest.
+message GetOperationResultResponse {
+    // The operation completed successfully.
+    message Complete {
+        temporal.api.common.v1.Payload payload = 1;
+        repeated Link links = 2;
+    }
+
+    message StillRunning {
+    }
+
+    message Timeout {
+    }
+
+    oneof variant {
+        Complete complete_success = 1;
+        // The operation completed unsuccessfully (failed or canceled).
+        UnsuccessfulOperationError operation_error = 2;
+        // The operation is still running, When waiting for completion, the caller may re-issue this request to start a
+        // new long poll.
+        StillRunning still_running = 3;
+        // The server gave up waiting for operation completion. The request may be retried by the caller.
+        // TODO: does the SDK need to return this or is this a server only result?
+        Timeout timeout = 4;
+    }
+}
+
 // A response indicating that the handler has successfully processed a request.
 message Response {
     // Variant must correlate to the corresponding Request's variant.
     oneof variant {
         StartOperationResponse start_operation = 1;
         CancelOperationResponse cancel_operation = 2;
+        GetOperationInfoResponse get_operation_info = 3;
+        GetOperationResultResponse get_operation_result = 4;
     }
 }
 
diff --git a/temporal/api/workflowservice/v1/request_response.proto b/temporal/api/workflowservice/v1/request_response.proto
index a0364f74..1d6eda65 100644
--- a/temporal/api/workflowservice/v1/request_response.proto
+++ b/temporal/api/workflowservice/v1/request_response.proto
@@ -2293,3 +2293,148 @@ message TriggerWorkflowRuleResponse {
     // True is the rule was applied, based on the rule conditions (predicate/visibility_query).
     bool applied = 1;
 }
+
+message StartNexusOperationRequest {
+    // The caller namespace. The endpoint below may point to a different namespace.
+    string namespace = 1;
+    // A registered endpoint. Mutually exclusive with task queue.
+    string endpoint = 2;
+    // Dispatch directly to a task queue on this namespace.
+    string task_queue = 3;
+
+    // Request headers to forward to the Handler.
+    map<string, string> header = 4;
+
+    // Name of service to start the operation in.
+    string service = 5;
+    // Operation name.
+    string operation = 6;
+    // A request ID that can be used as an idempotentency key.
+    string request_id = 7;
+    // Callback URL to call upon completion if the started operation is async.
+    string callback = 8;
+    // Full request body from the incoming HTTP request.
+    temporal.api.common.v1.Payload payload = 9;
+    // Header that is expected to be attached to the callback request when the operation completes.
+    map<string, string> callback_header = 10;
+    // Links contain caller information and can be attached to the operations started by the handler.
+    repeated temporal.api.nexus.v1.Link links = 11;
+}
+
+message StartNexusOperationResponse {
+    // An operation completed successfully.
+    message Sync {
+        temporal.api.common.v1.Payload payload = 1;
+        repeated temporal.api.nexus.v1.Link links = 2;
+    }
+
+    // The operation will complete asynchronously.
+    // The returned token can be used to reference this operation.
+    message Async {
+        string operation_token = 1;
+        repeated temporal.api.nexus.v1.Link links = 2;
+    }
+
+    oneof variant {
+        Sync sync_success = 1;
+        Async async_success = 2;
+        // The operation completed unsuccessfully (failed or canceled).
+        temporal.api.nexus.v1.UnsuccessfulOperationError operation_error = 3;
+    }
+}
+
+message CancelNexusOperationRequest {
+    // The caller namespace. The endpoint below may point to a different namespace.
+    string namespace = 1;
+    // A registered endpoint. Mutually exclusive with task queue.
+    string endpoint = 2;
+    // Dispatch directly to a task queue on this namespace.
+    string task_queue = 3;
+
+    // Request headers to forward to the Handler.
+    map<string, string> header = 4;
+
+    // Service name.
+    string service = 5;
+    // Operation name.
+    string operation = 6;
+    // Operation token as originally generated by a Handler via an async StartOperation response.
+    string operation_token = 7;
+}
+
+// If this response is returned, the cancelation request was successfully processed by a Handler.
+// The operation may ignore the cancelation request and end up in any terminal state.
+message CancelNexusOperationResponse {
+}
+
+message GetNexusOperationInfoRequest {
+    // The caller namespace. The endpoint below may point to a different namespace.
+    string namespace = 1;
+    // A registered endpoint. Mutually exclusive with task queue.
+    string endpoint = 2;
+    // Dispatch directly to a task queue on this namespace.
+    string task_queue = 3;
+
+    // Request headers to forward to the Handler.
+    map<string, string> header = 4;
+
+    // Service name.
+    string service = 5;
+    // Operation name.
+    string operation = 6;
+    // Operation token as originally generated by a Handler via an async StartOperation response.
+    string operation_token = 7;
+
+}
+message GetNexusOperationInfoResponse {
+    temporal.api.nexus.v1.OperationInfo info = 1;
+}
+
+message GetNexusOperationResultRequest {
+    // The caller namespace. The endpoint below may point to a different namespace.
+    string namespace = 1;
+    // A registered endpoint. Mutually exclusive with task queue.
+    string endpoint = 2;
+    // Dispatch directly to a task queue on this namespace.
+    string task_queue = 3;
+
+    // Request headers to forward to the Handler.
+    map<string, string> header = 4;
+
+    // Service name.
+    string service = 5;
+    // Operation name.
+    string operation = 6;
+    // Operation token as originally generated by a Handler via an async StartOperation response.
+    string operation_token = 7;
+
+    // If set and non-zero, reflects the duration the caller has indicated that it wants to wait for operation
+    // completion, turning the request into a long poll.
+    google.protobuf.Duration wait = 8;
+}
+
+message GetNexusOperationResultResponse {
+    // The operation completed successfully.
+    message Complete {
+        temporal.api.common.v1.Payload payload = 1;
+        repeated temporal.api.nexus.v1.Link links = 2;
+    }
+
+    message StillRunning {
+    }
+
+    message Timeout {
+    }
+
+    oneof variant {
+        Complete complete_success = 1;
+        // The operation completed unsuccessfully (failed or canceled).
+        temporal.api.nexus.v1.UnsuccessfulOperationError operation_error = 2;
+        // The operation is still running, When waiting for completion, the caller may re-issue this request to start a
+        // new long poll.
+        StillRunning still_running = 3;
+        // The server gave up waiting for operation completion. The request may be retried by the caller.
+        // TODO: does the SDK need to return this or is this a server only result?
+        Timeout timeout = 4;
+    }
+}
diff --git a/temporal/api/workflowservice/v1/service.proto b/temporal/api/workflowservice/v1/service.proto
index 352d9e4e..06467683 100644
--- a/temporal/api/workflowservice/v1/service.proto
+++ b/temporal/api/workflowservice/v1/service.proto
@@ -1173,4 +1173,34 @@ service WorkflowService {
         };
     }
 
+    // Start an arbitrary length operation. The response of the operation may be delivered synchronously (inline), or
+    // asynchronously, via a provided callback or the GetNexusOperationResult method.
+    //
+    // (-- api-linter: core::0127::http-annotation=disabled
+    //     aip.dev/not-precedent: Nexus has a separately defined HTTP API. --)
+    rpc StartNexusOperation (StartNexusOperationRequest) returns (StartNexusOperationResponse) {
+    }
+
+    // Request to cancel an operation. The operation may later complete as canceled or any other outcome. Handlers
+    // should ignore multiple cancelations of the same operation and return successfully if cancelation was already
+    // requested.
+    //
+    // (-- api-linter: core::0127::http-annotation=disabled
+    //     aip.dev/not-precedent: Nexus has a separately defined HTTP API. --)
+    rpc CancelNexusOperation (CancelNexusOperationRequest) returns (CancelNexusOperationResponse) {
+    }
+
+    // Retrieve operation result. Optionally specify a wait period to turn this request into a long poll.
+    //
+    // (-- api-linter: core::0127::http-annotation=disabled
+    //     aip.dev/not-precedent: Nexus has a separately defined HTTP API. --)
+    rpc GetNexusOperationInfo (GetNexusOperationInfoRequest) returns (GetNexusOperationInfoResponse) {
+    }
+
+    // Retrieve operation details.
+    //
+    // (-- api-linter: core::0127::http-annotation=disabled
+    //     aip.dev/not-precedent: Nexus has a separately defined HTTP API. --)
+    rpc GetNexusOperationResult (GetNexusOperationResultRequest) returns (GetNexusOperationResultResponse) {
+    }
 }