diff --git a/reana_commons/openapi_specifications/reana_server.json b/reana_commons/openapi_specifications/reana_server.json
index 3001071d..614fa026 100644
--- a/reana_commons/openapi_specifications/reana_server.json
+++ b/reana_commons/openapi_specifications/reana_server.json
@@ -2,7 +2,7 @@
   "info": {
     "description": "Submit workflows to be run on REANA Cloud",
     "title": "REANA Server",
-    "version": "0.9.1a3"
+    "version": "0.9.3"
   },
   "paths": {
     "/account/settings/linkedaccounts/": {},
@@ -3198,15 +3198,19 @@
             "schema": {
               "properties": {
                 "input_parameters": {
+                  "description": "Optional. Additional input parameters that override the ones in the workflow specification.",
                   "type": "object"
                 },
                 "operational_options": {
+                  "description": "Optional. Operational options for workflow execution.",
                   "type": "object"
                 },
                 "reana_specification": {
+                  "description": "Optional. Replace the original workflow specification with the given one. Only considered when restarting a workflow.",
                   "type": "object"
                 },
                 "restart": {
+                  "description": "Optional. If true, restart the given workflow.",
                   "type": "boolean"
                 }
               },
@@ -3595,6 +3599,11 @@
           },
           {
             "description": "Required. New workflow status.",
+            "enum": [
+              "start",
+              "stop",
+              "deleted"
+            ],
             "in": "query",
             "name": "status",
             "required": true,
@@ -3608,19 +3617,30 @@
             "type": "string"
           },
           {
-            "description": "Optional. Additional input parameters and operational options.",
+            "description": "Optional. Additional parameters to customise the change of workflow status.",
             "in": "body",
             "name": "parameters",
             "required": false,
             "schema": {
               "properties": {
-                "CACHE": {
-                  "type": "string"
-                },
                 "all_runs": {
+                  "description": "Optional. If true, delete all runs of the workflow. Only allowed when status is `deleted`.",
+                  "type": "boolean"
+                },
+                "input_parameters": {
+                  "description": "Optional. Additional input parameters that override the ones in the workflow specification. Only allowed when status is `start`.",
+                  "type": "object"
+                },
+                "operational_options": {
+                  "description": "Optional. Operational options for workflow execution. Only allowed when status is `start`.",
+                  "type": "object"
+                },
+                "restart": {
+                  "description": "Optional. If true, the workflow is a restart of another one. Only allowed when status is `start`.",
                   "type": "boolean"
                 },
                 "workspace": {
+                  "description": "Optional, but must be set to true if provided. If true, delete also the workspace of the workflow. Only allowed when status is `deleted`.",
                   "type": "boolean"
                 }
               },
diff --git a/reana_commons/openapi_specifications/reana_workflow_controller.json b/reana_commons/openapi_specifications/reana_workflow_controller.json
index 8fa267f5..9c2e3190 100644
--- a/reana_commons/openapi_specifications/reana_workflow_controller.json
+++ b/reana_commons/openapi_specifications/reana_workflow_controller.json
@@ -2,7 +2,7 @@
   "info": {
     "description": "Submit and manage workflows",
     "title": "REANA Workflow Controller",
-    "version": "0.9.1a2"
+    "version": "0.9.3"
   },
   "paths": {
     "/api/workflows": {
@@ -1116,19 +1116,30 @@
             "type": "string"
           },
           {
-            "description": "Optional. Additional input parameters and operational options for workflow execution. Possible parameters are `CACHE=on/off`, passed to disable caching of results in serial workflows, `all_runs=True/False` deletes all runs of a given workflow if status is set to deleted and `workspace=True/False` which deletes the workspace of a workflow.",
+            "description": "Optional. Additional parameters to customise the change of workflow status.",
             "in": "body",
             "name": "parameters",
             "required": false,
             "schema": {
               "properties": {
-                "CACHE": {
-                  "type": "string"
-                },
                 "all_runs": {
+                  "description": "Optional. If true, delete all runs of the workflow. Only allowed when status is `deleted`.",
+                  "type": "boolean"
+                },
+                "input_parameters": {
+                  "description": "Optional. Additional input parameters that override the ones in the workflow specification. Only allowed when status is `start`.",
+                  "type": "object"
+                },
+                "operational_options": {
+                  "description": "Optional. Operational options for workflow execution. Only allowed when status is `start`.",
+                  "type": "object"
+                },
+                "restart": {
+                  "description": "Optional. If true, the workflow is a restart of another one. Only allowed when status is `start`.",
                   "type": "boolean"
                 },
                 "workspace": {
+                  "description": "Optional, but must be set to true if provided. If true, delete also the workspace of the workflow. Only allowed when status is `deleted`.",
                   "type": "boolean"
                 }
               },