Allow non-user input through existing chat actions

.github/instructions/general-instructions.instructions.md

@@ -67,6 +67,7 @@ A spec change ripples into every `clients/<lang>/` mirror, so you often need to
 | Toolchain | Image | Notes |
 | --- | --- | --- |
 | JDK 17 (Kotlin client) | `docker.io/library/eclipse-temurin:17-jdk` | Gradle comes from the repo's `./gradlew` wrapper. |
+| .NET SDK 10 (.NET client) | `mcr.microsoft.com/dotnet/sdk:10.0` | Supports `.slnx`; the test host rolls forward from .NET 8. |
 
 Mount the **repo root** (the shared conformance fixtures under `types/test-cases/` are resolved by walking up from the working directory, so a client-dir-only mount fails) and keep build caches out of `$HOME`. Example — run the Kotlin client's tests:
 

clients/dotnet/src/AgentHostProtocol.Abstractions/Generated/Actions.generated.cs

@@ -1212,9 +1212,7 @@ public sealed record SessionDefaultChatChangedAction
     public string? DefaultChat { get; init; }
 }
 
-/// <summary>A new message has been sent to the agent, and a new turn starts.
-///
-/// A client is only allowed to send {@link MessageKind.User} messages.</summary>
+/// <summary>A new message has been sent to the agent, and a new turn starts.</summary>
 public sealed record ChatTurnStartedAction
 {
     public ActionType Type { get; init; } = ActionType.ChatTurnStarted;
@@ -1988,9 +1986,7 @@ public sealed record ChatTurnsLoadedAction
 /// message and kind in place.
 ///
 /// If the chat is idle when a queued message is set, the server SHOULD
-/// immediately consume it and start a new turn.
-///
-/// A client is only allowed to send {@link MessageKind.User} messages.</summary>
+/// immediately consume it and start a new turn.</summary>
 public sealed record ChatPendingMessageSetAction
 {
     public ActionType Type { get; init; } = ActionType.ChatPendingMessageSet;

clients/go/ahptypes/actions.generated.go

@@ -251,8 +251,6 @@ type SessionDefaultChatChangedAction struct {
 }
 
 // A new message has been sent to the agent, and a new turn starts.
-//
-// A client is only allowed to send {@link MessageKind.User} messages.
 type ChatTurnStartedAction struct {
 	Type ActionType `json:"type"`
 	// Turn identifier
@@ -789,8 +787,6 @@ type ChatReasoningAction struct {
 //
 // If the chat is idle when a queued message is set, the server SHOULD
 // immediately consume it and start a new turn.
-//
-// A client is only allowed to send {@link MessageKind.User} messages.
 type ChatPendingMessageSetAction struct {
 	Type ActionType `json:"type"`
 	// Whether this is a steering or queued message

clients/rust/crates/ahp-types/src/actions.rs

@@ -590,8 +590,6 @@ pub struct SessionDefaultChatChangedAction {
 }
 
 /// A new message has been sent to the agent, and a new turn starts.
-///
-/// A client is only allowed to send {@link MessageKind.User} messages.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct ChatTurnStartedAction {
@@ -1461,8 +1459,6 @@ pub struct SessionInputNeededRemovedAction {
 ///
 /// If the chat is idle when a queued message is set, the server SHOULD
 /// immediately consume it and start a new turn.
-///
-/// A client is only allowed to send {@link MessageKind.User} messages.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct ChatPendingMessageSetAction {

docs/.changes/20261029-non-user-chat-input.json

@@ -0,0 +1,5 @@
+{
+  "type": "changed",
+  "message": "Remove the User-only restriction on client-submitted messages in `chat/turnStarted` and `chat/pendingMessageSet`.",
+  "issues": [542]
+}

schema/actions.schema.json

@@ -747,7 +747,7 @@
     },
     "ChatTurnStartedAction": {
       "type": "object",
-      "description": "A new message has been sent to the agent, and a new turn starts.\n\nA client is only allowed to send {@link MessageKind.User} messages.",
+      "description": "A new message has been sent to the agent, and a new turn starts.",
       "properties": {
         "type": {
           "const": "chat/turnStarted"
@@ -1595,7 +1595,7 @@
     },
     "ChatPendingMessageSetAction": {
       "type": "object",
-      "description": "A pending message was set (upsert semantics: creates or replaces).\n\nBoth kinds are stored in {@link ChatState.queuedMessages}, including this\naction's `kind`. A new `id` appends an entry; an existing `id` replaces its\nmessage and kind in place.\n\nIf the chat is idle when a queued message is set, the server SHOULD\nimmediately consume it and start a new turn.\n\nA client is only allowed to send {@link MessageKind.User} messages.",
+      "description": "A pending message was set (upsert semantics: creates or replaces).\n\nBoth kinds are stored in {@link ChatState.queuedMessages}, including this\naction's `kind`. A new `id` appends an entry; an existing `id` replaces its\nmessage and kind in place.\n\nIf the chat is idle when a queued message is set, the server SHOULD\nimmediately consume it and start a new turn.",
       "properties": {
         "type": {
           "const": "chat/pendingMessageSet"

schema/commands.schema.json

@@ -8783,7 +8783,7 @@
     },
     "ChatTurnStartedAction": {
       "type": "object",
-      "description": "A new message has been sent to the agent, and a new turn starts.\n\nA client is only allowed to send {@link MessageKind.User} messages.",
+      "description": "A new message has been sent to the agent, and a new turn starts.",
       "properties": {
         "type": {
           "const": "chat/turnStarted"
@@ -9631,7 +9631,7 @@
     },
     "ChatPendingMessageSetAction": {
       "type": "object",
-      "description": "A pending message was set (upsert semantics: creates or replaces).\n\nBoth kinds are stored in {@link ChatState.queuedMessages}, including this\naction's `kind`. A new `id` appends an entry; an existing `id` replaces its\nmessage and kind in place.\n\nIf the chat is idle when a queued message is set, the server SHOULD\nimmediately consume it and start a new turn.\n\nA client is only allowed to send {@link MessageKind.User} messages.",
+      "description": "A pending message was set (upsert semantics: creates or replaces).\n\nBoth kinds are stored in {@link ChatState.queuedMessages}, including this\naction's `kind`. A new `id` appends an entry; an existing `id` replaces its\nmessage and kind in place.\n\nIf the chat is idle when a queued message is set, the server SHOULD\nimmediately consume it and start a new turn.",
       "properties": {
         "type": {
           "const": "chat/pendingMessageSet"

schema/errors.schema.json

@@ -9953,7 +9953,7 @@
     },
     "ChatTurnStartedAction": {
       "type": "object",
-      "description": "A new message has been sent to the agent, and a new turn starts.\n\nA client is only allowed to send {@link MessageKind.User} messages.",
+      "description": "A new message has been sent to the agent, and a new turn starts.",
       "properties": {
         "type": {
           "const": "chat/turnStarted"
@@ -10690,7 +10690,7 @@
     },
     "ChatPendingMessageSetAction": {
       "type": "object",
-      "description": "A pending message was set (upsert semantics: creates or replaces).\n\nBoth kinds are stored in {@link ChatState.queuedMessages}, including this\naction's `kind`. A new `id` appends an entry; an existing `id` replaces its\nmessage and kind in place.\n\nIf the chat is idle when a queued message is set, the server SHOULD\nimmediately consume it and start a new turn.\n\nA client is only allowed to send {@link MessageKind.User} messages.",
+      "description": "A pending message was set (upsert semantics: creates or replaces).\n\nBoth kinds are stored in {@link ChatState.queuedMessages}, including this\naction's `kind`. A new `id` appends an entry; an existing `id` replaces its\nmessage and kind in place.\n\nIf the chat is idle when a queued message is set, the server SHOULD\nimmediately consume it and start a new turn.",
       "properties": {
         "type": {
           "const": "chat/pendingMessageSet"

types/channels-chat/actions.ts

@@ -62,8 +62,6 @@ interface ToolCallActionBase {
 /**
  * A new message has been sent to the agent, and a new turn starts.
  *
- * A client is only allowed to send {@link MessageKind.User} messages.
- *
  * @category Chat Actions
  * @version 1
  * @clientDispatchable
@@ -777,8 +775,6 @@ export interface ChatTurnsLoadedAction {
  * If the chat is idle when a queued message is set, the server SHOULD
  * immediately consume it and start a new turn.
  *
- * A client is only allowed to send {@link MessageKind.User} messages.
- *
  * @category Chat Actions
  * @version 1
  * @clientDispatchable

types/test-cases/reducers/324-non-user-turn-origins-preserved.json

@@ -0,0 +1,96 @@
+{
+  "description": "non-user turn input preserves authorship and payloads in active turns and completed history without fabricated responses",
+  "reducer": "chat",
+  "initial": {
+    "resource": "ahp-chat:/non-user",
+    "title": "Non-user input",
+    "status": 1,
+    "modifiedAt": "2026-10-29T00:00:00.000Z",
+    "turns": []
+  },
+  "actions": [
+    {
+      "type": "chat/turnStarted",
+      "turnId": "agent-turn",
+      "startedAt": "2026-10-29T00:00:00.000Z",
+      "message": {
+        "text": "The worker finished its analysis.",
+        "origin": { "kind": "agent" },
+        "attachments": [
+          { "type": "simple", "label": "Worker result", "modelRepresentation": "The analysis passed.", "_meta": { "resultId": "result-1" } }
+        ],
+        "model": { "id": "model-1" },
+        "agent": { "uri": "ahp-agent:/reviewer" },
+        "_meta": { "sourceChat": "ahp-chat:/worker" }
+      }
+    },
+    { "type": "chat/turnComplete", "turnId": "agent-turn", "duration": 1000 },
+    {
+      "type": "chat/turnStarted",
+      "turnId": "notification-turn",
+      "startedAt": "2026-10-29T00:00:01.000Z",
+      "message": {
+        "text": "The worker conversation is now idle.",
+        "origin": { "kind": "systemNotification" }
+      }
+    },
+    { "type": "chat/turnComplete", "turnId": "notification-turn", "duration": 0 },
+    {
+      "type": "chat/turnStarted",
+      "turnId": "tool-turn",
+      "startedAt": "2026-10-29T00:00:02.000Z",
+      "message": {
+        "text": "Background work completed.",
+        "origin": { "kind": "tool" }
+      }
+    }
+  ],
+  "expected": {
+    "resource": "ahp-chat:/non-user",
+    "title": "Non-user input",
+    "status": 8,
+    "modifiedAt": "2026-10-29T00:00:02.000Z",
+    "turns": [
+      {
+        "id": "agent-turn",
+        "startedAt": "2026-10-29T00:00:00.000Z",
+        "duration": 1000,
+        "message": {
+          "text": "The worker finished its analysis.",
+          "origin": { "kind": "agent" },
+          "attachments": [
+            { "type": "simple", "label": "Worker result", "modelRepresentation": "The analysis passed.", "_meta": { "resultId": "result-1" } }
+          ],
+          "model": { "id": "model-1" },
+          "agent": { "uri": "ahp-agent:/reviewer" },
+          "_meta": { "sourceChat": "ahp-chat:/worker" }
+        },
+        "responseParts": [],
+        "usage": null,
+        "state": "complete"
+      },
+      {
+        "id": "notification-turn",
+        "startedAt": "2026-10-29T00:00:01.000Z",
+        "duration": 0,
+        "message": {
+          "text": "The worker conversation is now idle.",
+          "origin": { "kind": "systemNotification" }
+        },
+        "responseParts": [],
+        "usage": null,
+        "state": "complete"
+      }
+    ],
+    "activeTurn": {
+      "id": "tool-turn",
+      "startedAt": "2026-10-29T00:00:02.000Z",
+      "message": {
+        "text": "Background work completed.",
+        "origin": { "kind": "tool" }
+      },
+      "responseParts": [],
+      "usage": null
+    }
+  }
+}

types/test-cases/reducers/325-non-user-pending-origins-preserved.json

@@ -0,0 +1,96 @@
+{
+  "description": "non-user queued and steering input preserves authorship through upserts and queued turn consumption",
+  "reducer": "chat",
+  "initial": {
+    "resource": "ahp-chat:/non-user",
+    "title": "Non-user input",
+    "status": 1,
+    "modifiedAt": "2026-10-29T00:00:00.000Z",
+    "turns": []
+  },
+  "actions": [
+    {
+      "type": "chat/pendingMessageSet",
+      "kind": "queued",
+      "id": "agent-result",
+      "message": {
+        "text": "The worker finished its analysis.",
+        "origin": { "kind": "agent" },
+        "model": { "id": "model-1" },
+        "agent": { "uri": "ahp-agent:/reviewer" }
+      }
+    },
+    {
+      "type": "chat/pendingMessageSet",
+      "kind": "queued",
+      "id": "tool-result",
+      "message": { "text": "Background work completed.", "origin": { "kind": "tool" } }
+    },
+    {
+      "type": "chat/pendingMessageSet",
+      "kind": "steering",
+      "id": "notification",
+      "message": { "text": "Worker finishing.", "origin": { "kind": "systemNotification" } }
+    },
+    {
+      "type": "chat/pendingMessageSet",
+      "kind": "steering",
+      "id": "notification",
+      "message": { "text": "Worker finished.", "origin": { "kind": "systemNotification" }, "_meta": { "workerId": "worker-1" } }
+    },
+    {
+      "type": "chat/pendingMessageSet",
+      "kind": "steering",
+      "id": "notification",
+      "message": { "text": "Worker finished.", "origin": { "kind": "systemNotification" }, "_meta": { "workerId": "worker-1" } }
+    },
+    {
+      "type": "chat/turnStarted",
+      "turnId": "agent-turn",
+      "startedAt": "2026-10-29T00:00:01.000Z",
+      "queuedMessageId": "agent-result",
+      "message": {
+        "text": "The worker finished its analysis.",
+        "origin": { "kind": "agent" },
+        "model": { "id": "model-1" },
+        "agent": { "uri": "ahp-agent:/reviewer" }
+      }
+    }
+  ],
+  "expected": {
+    "resource": "ahp-chat:/non-user",
+    "title": "Non-user input",
+    "status": 8,
+    "modifiedAt": "2026-10-29T00:00:01.000Z",
+    "turns": [],
+    "activeTurn": {
+      "id": "agent-turn",
+      "startedAt": "2026-10-29T00:00:01.000Z",
+      "message": {
+        "text": "The worker finished its analysis.",
+        "origin": { "kind": "agent" },
+        "model": { "id": "model-1" },
+        "agent": { "uri": "ahp-agent:/reviewer" }
+      },
+      "responseParts": [],
+      "usage": null
+    },
+    "queuedMessages": [
+      {
+        "id": "tool-result",
+        "kind": "queued",
+        "message": { "text": "Background work completed.", "origin": { "kind": "tool" } }
+      },
+      {
+        "id": "notification",
+        "kind": "steering",
+        "message": { "text": "Worker finished.", "origin": { "kind": "systemNotification" }, "_meta": { "workerId": "worker-1" } }
+      }
+    ],
+    "steeringMessage": {
+      "id": "notification",
+      "kind": "steering",
+      "message": { "text": "Worker finished.", "origin": { "kind": "systemNotification" }, "_meta": { "workerId": "worker-1" } }
+    }
+  }
+}