Add new task queue kind to send worker commands (#763)

## What

Add `TASK_QUEUE_KIND_WORKER_COMMANDS` (value 3) to `TaskQueueKind` enum.

## Why

Worker-commands task queues are used for server-to-worker communication
(e.g. activity cancellations). They need to be distinguished from
user-defined queues so the server can handle them differently in metrics
and other areas. SDKs will set this kind when polling worker-commands
queues.

## How did you test it?

Proto-only change, no runtime behavior yet.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: rkannan82

openapi/openapiv2.json

@@ -1895,14 +1895,15 @@
           },
           {
             "name": "taskQueue.kind",
-            "description": "Default: TASK_QUEUE_KIND_NORMAL.\n\n - TASK_QUEUE_KIND_UNSPECIFIED: Tasks from any non workflow task may be unspecified.\n\nTask queue kind is used to differentiate whether a workflow task queue is sticky or \nnormal. If a task is not a workflow task, Task queue kind will sometimes be \nunspecified.\n - TASK_QUEUE_KIND_NORMAL: Tasks from a normal workflow task queue always include complete workflow history\n\nThe task queue specified by the user is always a normal task queue. There can be as many\nworkers as desired for a single normal task queue. All those workers may pick up tasks from\nthat queue.\n - TASK_QUEUE_KIND_STICKY: A sticky queue only includes new history since the last workflow task, and they are\nper-worker.\n\nSticky queues are created dynamically by each worker during their start up. They only exist\nfor the lifetime of the worker process. Tasks in a sticky task queue are only available to\nthe worker that created the sticky queue.\n\nSticky queues are only for workflow tasks. There are no sticky task queues for activities.",
+            "description": "Default: TASK_QUEUE_KIND_NORMAL.\n\n - TASK_QUEUE_KIND_UNSPECIFIED: Tasks from any non workflow task may be unspecified.\n\nTask queue kind is used to differentiate whether a workflow task queue is sticky or \nnormal. If a task is not a workflow task, Task queue kind will sometimes be \nunspecified.\n - TASK_QUEUE_KIND_NORMAL: Tasks from a normal workflow task queue always include complete workflow history\n\nThe task queue specified by the user is always a normal task queue. There can be as many\nworkers as desired for a single normal task queue. All those workers may pick up tasks from\nthat queue.\n - TASK_QUEUE_KIND_STICKY: A sticky queue only includes new history since the last workflow task, and they are\nper-worker.\n\nSticky queues are created dynamically by each worker during their start up. They only exist\nfor the lifetime of the worker process. Tasks in a sticky task queue are only available to\nthe worker that created the sticky queue.\n\nSticky queues are only for workflow tasks. There are no sticky task queues for activities.\n - TASK_QUEUE_KIND_WORKER_COMMANDS: A worker-commands task queue is used for server-to-worker communication (e.g. activity\ncancellations). These queues are ephemeral and per-worker-process — they exist only for\nthe lifetime of the worker process. Used with TASK_QUEUE_TYPE_NEXUS and polled via\nPollNexusTaskQueue.",
             "in": "query",
             "required": false,
             "type": "string",
             "enum": [
               "TASK_QUEUE_KIND_UNSPECIFIED",
               "TASK_QUEUE_KIND_NORMAL",
-              "TASK_QUEUE_KIND_STICKY"
+              "TASK_QUEUE_KIND_STICKY",
+              "TASK_QUEUE_KIND_WORKER_COMMANDS"
             ],
             "default": "TASK_QUEUE_KIND_UNSPECIFIED"
           },
@@ -6632,14 +6633,15 @@
           },
           {
             "name": "taskQueue.kind",
-            "description": "Default: TASK_QUEUE_KIND_NORMAL.\n\n - TASK_QUEUE_KIND_UNSPECIFIED: Tasks from any non workflow task may be unspecified.\n\nTask queue kind is used to differentiate whether a workflow task queue is sticky or \nnormal. If a task is not a workflow task, Task queue kind will sometimes be \nunspecified.\n - TASK_QUEUE_KIND_NORMAL: Tasks from a normal workflow task queue always include complete workflow history\n\nThe task queue specified by the user is always a normal task queue. There can be as many\nworkers as desired for a single normal task queue. All those workers may pick up tasks from\nthat queue.\n - TASK_QUEUE_KIND_STICKY: A sticky queue only includes new history since the last workflow task, and they are\nper-worker.\n\nSticky queues are created dynamically by each worker during their start up. They only exist\nfor the lifetime of the worker process. Tasks in a sticky task queue are only available to\nthe worker that created the sticky queue.\n\nSticky queues are only for workflow tasks. There are no sticky task queues for activities.",
+            "description": "Default: TASK_QUEUE_KIND_NORMAL.\n\n - TASK_QUEUE_KIND_UNSPECIFIED: Tasks from any non workflow task may be unspecified.\n\nTask queue kind is used to differentiate whether a workflow task queue is sticky or \nnormal. If a task is not a workflow task, Task queue kind will sometimes be \nunspecified.\n - TASK_QUEUE_KIND_NORMAL: Tasks from a normal workflow task queue always include complete workflow history\n\nThe task queue specified by the user is always a normal task queue. There can be as many\nworkers as desired for a single normal task queue. All those workers may pick up tasks from\nthat queue.\n - TASK_QUEUE_KIND_STICKY: A sticky queue only includes new history since the last workflow task, and they are\nper-worker.\n\nSticky queues are created dynamically by each worker during their start up. They only exist\nfor the lifetime of the worker process. Tasks in a sticky task queue are only available to\nthe worker that created the sticky queue.\n\nSticky queues are only for workflow tasks. There are no sticky task queues for activities.\n - TASK_QUEUE_KIND_WORKER_COMMANDS: A worker-commands task queue is used for server-to-worker communication (e.g. activity\ncancellations). These queues are ephemeral and per-worker-process — they exist only for\nthe lifetime of the worker process. Used with TASK_QUEUE_TYPE_NEXUS and polled via\nPollNexusTaskQueue.",
             "in": "query",
             "required": false,
             "type": "string",
             "enum": [
               "TASK_QUEUE_KIND_UNSPECIFIED",
               "TASK_QUEUE_KIND_NORMAL",
-              "TASK_QUEUE_KIND_STICKY"
+              "TASK_QUEUE_KIND_STICKY",
+              "TASK_QUEUE_KIND_WORKER_COMMANDS"
             ],
             "default": "TASK_QUEUE_KIND_UNSPECIFIED"
           },
@@ -16861,10 +16863,11 @@
       "enum": [
         "TASK_QUEUE_KIND_UNSPECIFIED",
         "TASK_QUEUE_KIND_NORMAL",
-        "TASK_QUEUE_KIND_STICKY"
+        "TASK_QUEUE_KIND_STICKY",
+        "TASK_QUEUE_KIND_WORKER_COMMANDS"
       ],
       "default": "TASK_QUEUE_KIND_UNSPECIFIED",
-      "description": " - TASK_QUEUE_KIND_UNSPECIFIED: Tasks from any non workflow task may be unspecified.\n\nTask queue kind is used to differentiate whether a workflow task queue is sticky or \nnormal. If a task is not a workflow task, Task queue kind will sometimes be \nunspecified.\n - TASK_QUEUE_KIND_NORMAL: Tasks from a normal workflow task queue always include complete workflow history\n\nThe task queue specified by the user is always a normal task queue. There can be as many\nworkers as desired for a single normal task queue. All those workers may pick up tasks from\nthat queue.\n - TASK_QUEUE_KIND_STICKY: A sticky queue only includes new history since the last workflow task, and they are\nper-worker.\n\nSticky queues are created dynamically by each worker during their start up. They only exist\nfor the lifetime of the worker process. Tasks in a sticky task queue are only available to\nthe worker that created the sticky queue.\n\nSticky queues are only for workflow tasks. There are no sticky task queues for activities."
+      "description": " - TASK_QUEUE_KIND_UNSPECIFIED: Tasks from any non workflow task may be unspecified.\n\nTask queue kind is used to differentiate whether a workflow task queue is sticky or \nnormal. If a task is not a workflow task, Task queue kind will sometimes be \nunspecified.\n - TASK_QUEUE_KIND_NORMAL: Tasks from a normal workflow task queue always include complete workflow history\n\nThe task queue specified by the user is always a normal task queue. There can be as many\nworkers as desired for a single normal task queue. All those workers may pick up tasks from\nthat queue.\n - TASK_QUEUE_KIND_STICKY: A sticky queue only includes new history since the last workflow task, and they are\nper-worker.\n\nSticky queues are created dynamically by each worker during their start up. They only exist\nfor the lifetime of the worker process. Tasks in a sticky task queue are only available to\nthe worker that created the sticky queue.\n\nSticky queues are only for workflow tasks. There are no sticky task queues for activities.\n - TASK_QUEUE_KIND_WORKER_COMMANDS: A worker-commands task queue is used for server-to-worker communication (e.g. activity\ncancellations). These queues are ephemeral and per-worker-process — they exist only for\nthe lifetime of the worker process. Used with TASK_QUEUE_TYPE_NEXUS and polled via\nPollNexusTaskQueue."
     },
     "v1TaskQueueReachability": {
       "type": "object",

openapi/openapiv3.yaml

@@ -1812,6 +1812,7 @@ paths:
               - TASK_QUEUE_KIND_UNSPECIFIED
               - TASK_QUEUE_KIND_NORMAL
               - TASK_QUEUE_KIND_STICKY
+              - TASK_QUEUE_KIND_WORKER_COMMANDS
             type: string
             format: enum
         - name: taskQueue.normalName
@@ -6046,6 +6047,7 @@ paths:
               - TASK_QUEUE_KIND_UNSPECIFIED
               - TASK_QUEUE_KIND_NORMAL
               - TASK_QUEUE_KIND_STICKY
+              - TASK_QUEUE_KIND_WORKER_COMMANDS
             type: string
             format: enum
         - name: taskQueue.normalName
@@ -14787,6 +14789,7 @@ components:
             - TASK_QUEUE_KIND_UNSPECIFIED
             - TASK_QUEUE_KIND_NORMAL
             - TASK_QUEUE_KIND_STICKY
+            - TASK_QUEUE_KIND_WORKER_COMMANDS
           type: string
           description: 'Default: TASK_QUEUE_KIND_NORMAL.'
           format: enum

temporal/api/enums/v1/task_queue.proto

@@ -31,6 +31,11 @@ enum TaskQueueKind {
     //
     // Sticky queues are only for workflow tasks. There are no sticky task queues for activities.
     TASK_QUEUE_KIND_STICKY = 2;
+    // A worker-commands task queue is used for server-to-worker communication (e.g. activity
+    // cancellations). These queues are ephemeral and per-worker-process — they exist only for
+    // the lifetime of the worker process. Used with TASK_QUEUE_TYPE_NEXUS and polled via
+    // PollNexusTaskQueue.
+    TASK_QUEUE_KIND_WORKER_COMMANDS = 3;
 }
 
 enum TaskQueueType {