game/internal/controller/order.go

@@ -109,11 +109,11 @@ func (c *Controller) applyCommand(actor string, cmd order.DecodableCommand) (err
 	}
 
 	if ge, ok := errors.AsType[*e.GenericError](err); ok {
-		m.Result(ge.Code)
+		m.Result(ge.Code, ge.Error())
 	} else if err != nil {
 		panic(fmt.Errorf("error applying command has unknown origin: %w", err))
 	} else {
-		m.Result(0)
+		m.Result(0, "")
 	}
 
 	return

game/internal/repo/repo_test.go

@@ -75,14 +75,14 @@ func TestSaveOrder(t *testing.T) {
 	for i := range o.Commands {
 		if v, ok := order.AsCommand[*order.CommandRaceVote](o.Commands[i]); ok {
 			m := &v.CommandMeta
-			m.Result(0)
+			m.Result(0, "")
 		} else if v, ok := order.AsCommand[*order.CommandRaceQuit](o.Commands[i]); ok {
-			v.Result(10)
+			v.Result(10, "race quit failed")
 		} else if v, ok := order.AsCommand[*order.CommandShipClassCreate](o.Commands[i]); ok {
 			m := &v.CommandMeta
-			m.Result(33)
+			m.Result(33, "ship class create failed")
 		} else if v, ok := order.AsCommand[*order.CommandShipGroupMerge](o.Commands[i]); ok {
-			v.Result(0)
+			v.Result(0, "")
 		}
 	}
 

game/openapi.yaml

@@ -520,6 +520,16 @@ components:
             `0` when the command was applied, a non-zero `GenericError`
             code (shelves `2xxx`/`3xxx` in `pkg/error/generic.go`) when
             the command was rejected. Omitted on requests.
+        cmdErrorMessage:
+          type: string
+          description: |
+            Per-command rejection reason, formatted by the engine's
+            `GenericError.Error()` (e.g.
+            `Entity does not exists: ship type "Drone"`). Set alongside
+            `cmdApplied=false`/`cmdErrorCode!=0`, omitted when the
+            command was applied. Provided so clients can surface the
+            specific reason without keeping their own code → text
+            catalog in sync with the engine.
     CommandType:
       type: string
       description: Discriminator identifying the game command variant carried in a `cmd` element.

pkg/model/order/order.go

@@ -124,6 +124,7 @@ type CommandMeta struct {
 	CmdID      string      `json:"cmdId" binding:"required,uuid_rfc4122"`
 	CmdApplied *bool       `json:"cmdApplied,omitempty"`
 	CmdErrCode *int        `json:"cmdErrorCode,omitempty"`
+	CmdErrMsg  *string     `json:"cmdErrorMessage,omitempty"`
 }
 
 func (cm CommandMeta) CommandType() CommandType {
@@ -134,9 +135,18 @@ func (cm CommandMeta) CommandID() string {
 	return cm.CmdID
 }
 
-func (cm *CommandMeta) Result(errCode int) {
+// Result records the per-command outcome on the meta. errCode == 0 marks
+// the command as applied and clears CmdErrMsg; non-zero records the
+// rejection along with the human-readable engine message so clients can
+// surface the reason without their own code-to-text catalog.
+func (cm *CommandMeta) Result(errCode int, errMsg string) {
 	cm.CmdErrCode = &errCode
 	cm.CmdApplied = new(bool(errCode == 0))
+	if errCode == 0 {
+		cm.CmdErrMsg = nil
+		return
+	}
+	cm.CmdErrMsg = &errMsg
 }
 
 type CommandRaceQuit struct {

pkg/schema/fbs/order.fbs

@@ -193,6 +193,12 @@ table CommandItem {
   cmd_applied: bool = null;
   cmd_error_code: int64 = null;
   payload: CommandPayload (required);
+  // Human-readable failure reason returned by the engine when
+  // `cmd_applied = false`. Appended after `payload` to preserve the
+  // wire offsets of existing slots (FBS field IDs are allocated in
+  // declaration order, so inserting in the middle would shift every
+  // later slot). Omitted on requests and on applied commands.
+  cmd_error_message: string;
 }
 
 // UserGamesCommand is the signed-gRPC request payload for

pkg/schema/fbs/order/CommandItem.go

@@ -96,8 +96,16 @@ func (rcv *CommandItem) Payload(obj *flatbuffers.Table) bool {
 	return false
 }
 
+func (rcv *CommandItem) CmdErrorMessage() []byte {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(14))
+	if o != 0 {
+		return rcv._tab.ByteVector(o + rcv._tab.Pos)
+	}
+	return nil
+}
+
 func CommandItemStart(builder *flatbuffers.Builder) {
-	builder.StartObject(5)
+	builder.StartObject(6)
 }
 func CommandItemAddCmdId(builder *flatbuffers.Builder, cmdId flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(cmdId), 0)
@@ -116,6 +124,9 @@ func CommandItemAddPayloadType(builder *flatbuffers.Builder, payloadType Command
 func CommandItemAddPayload(builder *flatbuffers.Builder, payload flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(4, flatbuffers.UOffsetT(payload), 0)
 }
+func CommandItemAddCmdErrorMessage(builder *flatbuffers.Builder, cmdErrorMessage flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(5, flatbuffers.UOffsetT(cmdErrorMessage), 0)
+}
 func CommandItemEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/transcoder/order.go

@@ -125,6 +125,7 @@ type encodedCommand struct {
 	cmdID         string
 	cmdApplied    *bool
 	cmdErrCode    *int
+	cmdErrMsg     *string
 	payloadType   fbs.CommandPayload
 	payloadOffset flatbuffers.UOffsetT
 }
@@ -404,6 +405,7 @@ func encodedCommandFromMeta(meta model.CommandMeta, payloadType fbs.CommandPaylo
 		cmdID:         meta.CmdID,
 		cmdApplied:    cloneBoolPointer(meta.CmdApplied),
 		cmdErrCode:    cloneIntPointer(meta.CmdErrCode),
+		cmdErrMsg:     cloneStringPointer(meta.CmdErrMsg),
 		payloadType:   payloadType,
 		payloadOffset: payloadOffset,
 	}
@@ -423,6 +425,11 @@ func decodeOrderCommand(flatCommand *fbs.CommandItem, index int) (model.Decodabl
 		commandMeta.CmdErrCode = &decodedCmdErrCode
 	}
 
+	if cmdErrMsg := flatCommand.CmdErrorMessage(); cmdErrMsg != nil {
+		decodedCmdErrMsg := string(cmdErrMsg)
+		commandMeta.CmdErrMsg = &decodedCmdErrMsg
+	}
+
 	payloadType := flatCommand.PayloadType()
 	if payloadType == fbs.CommandPayloadNONE {
 		return nil, fmt.Errorf("decode order command %d: payload type is NONE", index)
@@ -915,6 +922,15 @@ func cloneIntPointer(value *int) *int {
 	return &cloned
 }
 
+func cloneStringPointer(value *string) *string {
+	if value == nil {
+		return nil
+	}
+
+	cloned := *value
+	return &cloned
+}
+
 // UserGamesCommandToPayload converts model.UserGamesCommand to
 // FlatBuffers bytes suitable for the authenticated gateway transport.
 // `GameID` is required.
@@ -1293,6 +1309,10 @@ func encodeCommandItemVector(builder *flatbuffers.Builder, commands []model.Deco
 			return 0, fmt.Errorf("encode %s: %w", opLabel, err)
 		}
 		cmdID := builder.CreateString(encoded.cmdID)
+		var cmdErrMsg flatbuffers.UOffsetT
+		if encoded.cmdErrMsg != nil {
+			cmdErrMsg = builder.CreateString(*encoded.cmdErrMsg)
+		}
 		fbs.CommandItemStart(builder)
 		fbs.CommandItemAddCmdId(builder, cmdID)
 		if encoded.cmdApplied != nil {
@@ -1303,6 +1323,9 @@ func encodeCommandItemVector(builder *flatbuffers.Builder, commands []model.Deco
 		}
 		fbs.CommandItemAddPayloadType(builder, encoded.payloadType)
 		fbs.CommandItemAddPayload(builder, encoded.payloadOffset)
+		if encoded.cmdErrMsg != nil {
+			fbs.CommandItemAddCmdErrorMessage(builder, cmdErrMsg)
+		}
 		offsets[i] = fbs.CommandItemEnd(builder)
 	}
 	if len(offsets) == 0 {

pkg/transcoder/order_test.go

@@ -94,6 +94,7 @@ func TestUserGamesOrderResponsePayloadRoundTrip(t *testing.T) {
 	applied := true
 	rejected := false
 	errCode := 7
+	errMsg := "rename failed: planet does not exist"
 	source := &model.UserGamesOrder{
 		GameID:    uuid.MustParse("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"),
 		UpdatedAt: 99,
@@ -104,7 +105,7 @@ func TestUserGamesOrderResponsePayloadRoundTrip(t *testing.T) {
 				Name:        "alpha",
 			},
 			&model.CommandPlanetRename{
-				CommandMeta: commandMeta("cmd-2", model.CommandTypePlanetRename, &rejected, &errCode),
+				CommandMeta: commandMetaWithMsg("cmd-2", model.CommandTypePlanetRename, &rejected, &errCode, &errMsg),
 				Number:      6,
 				Name:        "beta",
 			},
@@ -254,10 +255,15 @@ func TestInt64ToInt(t *testing.T) {
 }
 
 func commandMeta(id string, cmdType model.CommandType, applied *bool, errCode *int) model.CommandMeta {
+	return commandMetaWithMsg(id, cmdType, applied, errCode, nil)
+}
+
+func commandMetaWithMsg(id string, cmdType model.CommandType, applied *bool, errCode *int, errMsg *string) model.CommandMeta {
 	return model.CommandMeta{
 		CmdType:    cmdType,
 		CmdID:      id,
 		CmdApplied: applied,
 		CmdErrCode: errCode,
+		CmdErrMsg:  errMsg,
 	}
 }

ui/frontend/src/lib/sidebar/order-tab.svelte

@@ -153,6 +153,10 @@ Tests exercise the tab through `__galaxyDebug.seedOrderDraft`
 	function statusOf(cmd: OrderCommand): CommandStatus {
 		return draft?.statuses[cmd.id] ?? "draft";
 	}
+
+	function errorMessageOf(cmd: OrderCommand): string | null {
+		return draft?.errorMessages[cmd.id] ?? null;
+	}
 </script>
 
 <section class="tool" data-testid="sidebar-tool-order">
@@ -191,6 +195,7 @@ Tests exercise the tab through `__galaxyDebug.seedOrderDraft`
 		<ol class="commands" data-testid="order-list">
 			{#each draft.commands as cmd, index (cmd.id)}
 				{@const status = statusOf(cmd)}
+				{@const errorReason = errorMessageOf(cmd)}
 				<li
 					class="command status-{status}"
 					data-testid="order-command-{index}"
@@ -200,6 +205,14 @@ Tests exercise the tab through `__galaxyDebug.seedOrderDraft`
 					<span class="label" data-testid="order-command-label-{index}">
 						{describe(cmd)}
 					</span>
+					{#if status === "rejected" && errorReason !== null}
+						<span
+							class="error-reason"
+							data-testid="order-command-error-{index}"
+						>
+							{errorReason}
+						</span>
+					{/if}
 					<span
 						class="sr-only"
 						data-testid="order-command-status-{index}"
@@ -314,6 +327,16 @@ Tests exercise the tab through `__galaxyDebug.seedOrderDraft`
 		min-width: 0;
 		overflow-wrap: anywhere;
 	}
+	.error-reason {
+		grid-column: 2;
+		min-width: 0;
+		overflow-wrap: anywhere;
+		margin-top: 0.1rem;
+		color: var(--color-danger);
+		font-size: 0.75rem;
+		font-style: italic;
+		line-height: 1.25;
+	}
 	.banner {
 		margin: 0 0 0.5rem;
 		padding: 0.5rem 0.75rem;

ui/frontend/src/proto/galaxy/fbs/order/command-item.ts

@@ -75,8 +75,15 @@ payload<T extends flatbuffers.Table>(obj:any):any|null {
   return offset ? this.bb!.__union(obj, this.bb_pos + offset) : null;
 }
 
+cmdErrorMessage():string|null
+cmdErrorMessage(optionalEncoding:flatbuffers.Encoding):string|Uint8Array|null
+cmdErrorMessage(optionalEncoding?:any):string|Uint8Array|null {
+  const offset = this.bb!.__offset(this.bb_pos, 14);
+  return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
+}
+
 static startCommandItem(builder:flatbuffers.Builder) {
-  builder.startObject(5);
+  builder.startObject(6);
 }
 
 static addCmdId(builder:flatbuffers.Builder, cmdIdOffset:flatbuffers.Offset) {
@@ -84,11 +91,11 @@ static addCmdId(builder:flatbuffers.Builder, cmdIdOffset:flatbuffers.Offset) {
 }
 
 static addCmdApplied(builder:flatbuffers.Builder, cmdApplied:boolean) {
-  builder.addFieldInt8(1, +cmdApplied, null);
+  builder.addFieldInt8(1, +cmdApplied, 0);
 }
 
 static addCmdErrorCode(builder:flatbuffers.Builder, cmdErrorCode:bigint) {
-  builder.addFieldInt64(2, cmdErrorCode, null);
+  builder.addFieldInt64(2, cmdErrorCode, BigInt(0));
 }
 
 static addPayloadType(builder:flatbuffers.Builder, payloadType:CommandPayload) {
@@ -99,13 +106,17 @@ static addPayload(builder:flatbuffers.Builder, payloadOffset:flatbuffers.Offset)
   builder.addFieldOffset(4, payloadOffset, 0);
 }
 
+static addCmdErrorMessage(builder:flatbuffers.Builder, cmdErrorMessageOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(5, cmdErrorMessageOffset, 0);
+}
+
 static endCommandItem(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   builder.requiredField(offset, 12) // payload
   return offset;
 }
 
-static createCommandItem(builder:flatbuffers.Builder, cmdIdOffset:flatbuffers.Offset, cmdApplied:boolean|null, cmdErrorCode:bigint|null, payloadType:CommandPayload, payloadOffset:flatbuffers.Offset):flatbuffers.Offset {
+static createCommandItem(builder:flatbuffers.Builder, cmdIdOffset:flatbuffers.Offset, cmdApplied:boolean|null, cmdErrorCode:bigint|null, payloadType:CommandPayload, payloadOffset:flatbuffers.Offset, cmdErrorMessageOffset:flatbuffers.Offset):flatbuffers.Offset {
   CommandItem.startCommandItem(builder);
   CommandItem.addCmdId(builder, cmdIdOffset);
   if (cmdApplied !== null)
@@ -114,6 +125,7 @@ static createCommandItem(builder:flatbuffers.Builder, cmdIdOffset:flatbuffers.Of
     CommandItem.addCmdErrorCode(builder, cmdErrorCode);
   CommandItem.addPayloadType(builder, payloadType);
   CommandItem.addPayload(builder, payloadOffset);
+  CommandItem.addCmdErrorMessage(builder, cmdErrorMessageOffset);
   return CommandItem.endCommandItem(builder);
 }
 
@@ -127,7 +139,8 @@ unpack(): CommandItemT {
       const temp = unionToCommandPayload(this.payloadType(), this.payload.bind(this));
       if(temp === null) { return null; }
       return temp.unpack()
-  })()
+  })(),
+    this.cmdErrorMessage()
   );
 }
 
@@ -142,6 +155,7 @@ unpackTo(_o: CommandItemT): void {
       if(temp === null) { return null; }
       return temp.unpack()
   })();
+  _o.cmdErrorMessage = this.cmdErrorMessage();
 }
 }
 
@@ -151,20 +165,23 @@ constructor(
   public cmdApplied: boolean|null = null,
   public cmdErrorCode: bigint|null = null,
   public payloadType: CommandPayload = CommandPayload.NONE,
-  public payload: CommandFleetMergeT|CommandFleetSendT|CommandPlanetProduceT|CommandPlanetRenameT|CommandPlanetRouteRemoveT|CommandPlanetRouteSetT|CommandRaceQuitT|CommandRaceRelationT|CommandRaceVoteT|CommandScienceCreateT|CommandScienceRemoveT|CommandShipClassCreateT|CommandShipClassMergeT|CommandShipClassRemoveT|CommandShipGroupBreakT|CommandShipGroupDismantleT|CommandShipGroupJoinFleetT|CommandShipGroupLoadT|CommandShipGroupMergeT|CommandShipGroupSendT|CommandShipGroupTransferT|CommandShipGroupUnloadT|CommandShipGroupUpgradeT|null = null
+  public payload: CommandFleetMergeT|CommandFleetSendT|CommandPlanetProduceT|CommandPlanetRenameT|CommandPlanetRouteRemoveT|CommandPlanetRouteSetT|CommandRaceQuitT|CommandRaceRelationT|CommandRaceVoteT|CommandScienceCreateT|CommandScienceRemoveT|CommandShipClassCreateT|CommandShipClassMergeT|CommandShipClassRemoveT|CommandShipGroupBreakT|CommandShipGroupDismantleT|CommandShipGroupJoinFleetT|CommandShipGroupLoadT|CommandShipGroupMergeT|CommandShipGroupSendT|CommandShipGroupTransferT|CommandShipGroupUnloadT|CommandShipGroupUpgradeT|null = null,
+  public cmdErrorMessage: string|Uint8Array|null = null
 ){}
 
 
 pack(builder:flatbuffers.Builder): flatbuffers.Offset {
   const cmdId = (this.cmdId !== null ? builder.createString(this.cmdId!) : 0);
   const payload = builder.createObjectOffset(this.payload);
+  const cmdErrorMessage = (this.cmdErrorMessage !== null ? builder.createString(this.cmdErrorMessage!) : 0);
 
   return CommandItem.createCommandItem(builder,
     cmdId,
     this.cmdApplied,
     this.cmdErrorCode,
     this.payloadType,
-    payload
+    payload,
+    cmdErrorMessage
   );
 }
 }

ui/frontend/src/sync/order-draft.svelte.ts

@@ -95,6 +95,15 @@ export interface PausedBanner {
 export class OrderDraftStore {
 	commands: OrderCommand[] = $state([]);
 	statuses: Record<string, CommandStatus> = $state({});
+	/**
+	 * errorMessages carries the engine-formatted rejection reason for
+	 * each rejected command, keyed by `cmdId`. Populated from
+	 * `submitOrder` responses and from the server-stored order on
+	 * `hydrateFromServer`. Cleared when a command is re-mutated or
+	 * removed. The order tab renders the message inline on rejected
+	 * rows so the player can act without inspecting the network log.
+	 */
+	errorMessages: Record<string, string> = $state({});
 	updatedAt = $state(0);
 	status: Status = $state("idle");
 	error: string | null = $state(null);
@@ -261,16 +270,29 @@ export class OrderDraftStore {
 			this.commands = fetched.commands;
 			this.updatedAt = fetched.updatedAt;
 			this.recomputeStatuses();
-			// Server-fetched commands echo cmdApplied=true for entries
-			// that survived previous turns; keep them as `applied` so
-			// the overlay continues to project them on the inspector.
+			// The engine echoes per-command `cmdApplied`/`cmdErrorCode`
+			// /`cmdErrorMessage` on every stored order entry. Hydrate
+			// the in-memory status + error maps from the fetched
+			// snapshot so a returning player sees the same per-command
+			// verdict (and rejection reason) the previous submission
+			// produced, instead of a synthetic blanket `applied` derived
+			// from the local cache.
 			const next = { ...this.statuses };
+			const nextErrors: Record<string, string> = {};
 			for (const cmd of this.commands) {
-				if (next[cmd.id] === "valid") {
+				const status = fetched.statuses.get(cmd.id);
+				if (status !== undefined && next[cmd.id] !== "invalid") {
+					next[cmd.id] = status;
+				} else if (next[cmd.id] === "valid") {
 					next[cmd.id] = "applied";
 				}
+				const msg = fetched.errorMessages.get(cmd.id);
+				if (msg !== null && msg !== undefined && msg !== "") {
+					nextErrors[cmd.id] = msg;
+				}
 			}
 			this.statuses = next;
+			this.errorMessages = nextErrors;
 			await this.persist();
 			if ((this.syncStatus as SyncStatus) !== "paused") {
 				this.syncStatus = "synced";
@@ -384,11 +406,15 @@ export class OrderDraftStore {
 		}
 		this.commands = nextCommands;
 		const nextStatuses = { ...this.statuses };
+		const nextErrors = { ...this.errorMessages };
 		for (const id of removed) {
 			delete nextStatuses[id];
+			delete nextErrors[id];
 		}
 		nextStatuses[command.id] = validateCommand(command);
+		delete nextErrors[command.id];
 		this.statuses = nextStatuses;
+		this.errorMessages = nextErrors;
 		await this.persist();
 		this.scheduleSync();
 	}
@@ -408,8 +434,11 @@ export class OrderDraftStore {
 		this.clearConflictForMutation();
 		this.commands = next;
 		const nextStatuses = { ...this.statuses };
+		const nextErrors = { ...this.errorMessages };
 		delete nextStatuses[id];
+		delete nextErrors[id];
 		this.statuses = nextStatuses;
+		this.errorMessages = nextErrors;
 		await this.persist();
 		this.scheduleSync();
 	}
@@ -484,6 +513,7 @@ export class OrderDraftStore {
 		if (this.status !== "ready") return;
 		this.commands = [];
 		this.statuses = {};
+		this.errorMessages = {};
 		this.updatedAt = 0;
 		this.conflictBanner = null;
 		this.pausedBanner = null;
@@ -571,20 +601,18 @@ export class OrderDraftStore {
 					this.applyResultsInternal(
 						outcome.result.results,
 						outcome.result.updatedAt,
+						outcome.result.errorMessages,
 					);
-					// Even with `result.ok === true` an individual
-					// command may have been rejected by the engine
-					// (e.g. validation passed transcoders but failed
-					// the in-game rule). Surface that as an error in
-					// the sync bar so the player notices and can fix
-					// or remove the offending command.
-					const anyRejected = Array.from(
-						outcome.result.results.values(),
-					).some((s) => s === "rejected");
-					this.syncStatus = anyRejected ? "error" : "synced";
-					this.syncError = anyRejected
-						? "engine rejected one or more commands"
-						: null;
+					// A `success` outcome means the gateway → backend →
+					// engine round trip completed cleanly, even when
+					// individual commands were rejected by the in-game
+					// rules. Per-command rejection is a player-fixable
+					// state surfaced via the row's `rejected` highlight
+					// and the inline reason; the sync bar stays green so
+					// the banner + Retry button are reserved for genuine
+					// transport / engine failures the auto-retry can fix.
+					this.syncStatus = "synced";
+					this.syncError = null;
 					break;
 				}
 				case "rejected": {
@@ -669,9 +697,11 @@ export class OrderDraftStore {
 	private applyResultsInternal(
 		results: Map<string, CommandStatus>,
 		updatedAt: number,
+		errorMessages?: Map<string, string | null>,
 	): void {
 		const liveIds = new Set(this.commands.map((cmd) => cmd.id));
 		const next = { ...this.statuses };
+		const nextErrors = { ...this.errorMessages };
 		for (const [id, status] of results.entries()) {
 			// Drop verdicts for commands the user removed while the
 			// request was in flight — they are no longer in the
@@ -679,8 +709,15 @@ export class OrderDraftStore {
 			// confuse the order tab and the overlay.
 			if (!liveIds.has(id)) continue;
 			next[id] = status;
+			const msg = errorMessages?.get(id) ?? null;
+			if (msg !== null && msg !== "") {
+				nextErrors[id] = msg;
+			} else {
+				delete nextErrors[id];
+			}
 		}
 		this.statuses = next;
+		this.errorMessages = nextErrors;
 		this.updatedAt = updatedAt;
 	}
 

ui/frontend/src/sync/order-load.ts

@@ -63,6 +63,17 @@ export class OrderLoadError extends Error {
 
 export interface FetchedOrder {
 	commands: OrderCommand[];
+	// Per-command status keyed by cmdId. Populated from the engine's
+	// stored order so a returning player sees the same per-command
+	// verdict (applied / rejected) the previous submission produced —
+	// not a synthetic "applied" derived from the local cache.
+	statuses: Map<string, "applied" | "rejected">;
+	// Per-command engine-formatted error code/message, keyed by cmdId.
+	// Both maps carry an entry for every loaded command; the value is
+	// null when the command was applied (no error). The message lets
+	// the UI surface the rejection reason without a code → text catalog.
+	errorCodes: Map<string, number | null>;
+	errorMessages: Map<string, string | null>;
 	updatedAt: number;
 }
 
@@ -119,7 +130,13 @@ function decodeResponse(payload: Uint8Array): FetchedOrder {
 	const buffer = new ByteBuffer(payload);
 	const response = UserGamesOrderGetResponse.getRootAsUserGamesOrderGetResponse(buffer);
 	if (!response.found()) {
-		return { commands: [], updatedAt: 0 };
+		return {
+			commands: [],
+			statuses: new Map(),
+			errorCodes: new Map(),
+			errorMessages: new Map(),
+			updatedAt: 0,
+		};
 	}
 	const order = response.order();
 	if (order === null) {
@@ -130,6 +147,9 @@ function decodeResponse(payload: Uint8Array): FetchedOrder {
 		);
 	}
 	const commands: OrderCommand[] = [];
+	const statuses = new Map<string, "applied" | "rejected">();
+	const errorCodes = new Map<string, number | null>();
+	const errorMessages = new Map<string, string | null>();
 	const length = order.commandsLength();
 	for (let i = 0; i < length; i++) {
 		const item = order.commands(i);
@@ -137,9 +157,20 @@ function decodeResponse(payload: Uint8Array): FetchedOrder {
 		const cmd = decodeCommand(item);
 		if (cmd === null) continue;
 		commands.push(cmd);
+		// The engine echoes `cmd_applied = false` only when the order
+		// was rejected per-command; missing / true both mean applied.
+		const applied = item.cmdApplied();
+		statuses.set(cmd.id, applied === false ? "rejected" : "applied");
+		const code = item.cmdErrorCode();
+		errorCodes.set(cmd.id, code === null ? null : Number(code));
+		const msg = item.cmdErrorMessage();
+		errorMessages.set(cmd.id, msg === null ? null : msg);
 	}
 	return {
 		commands,
+		statuses,
+		errorCodes,
+		errorMessages,
 		updatedAt: Number(order.updatedAt()),
 	};
 }

ui/frontend/src/sync/submit.ts

@@ -82,6 +82,7 @@ export interface SubmitSuccess {
 	ok: true;
 	results: Map<string, CommandOutcome>;
 	errorCodes: Map<string, number | null>;
+	errorMessages: Map<string, string | null>;
 	updatedAt: number;
 }
 
@@ -511,6 +512,7 @@ function decodeOrderResponse(
 ): SubmitSuccess {
 	const results = new Map<string, CommandOutcome>();
 	const errorCodes = new Map<string, number | null>();
+	const errorMessages = new Map<string, string | null>();
 	let updatedAt = 0;
 
 	if (payload.length === 0) {
@@ -518,8 +520,9 @@ function decodeOrderResponse(
 		for (const cmd of commands) {
 			results.set(cmd.id, "applied");
 			errorCodes.set(cmd.id, null);
+			errorMessages.set(cmd.id, null);
 		}
-		return { ok: true, results, errorCodes, updatedAt };
+		return { ok: true, results, errorCodes, errorMessages, updatedAt };
 	}
 
 	const buffer = new ByteBuffer(payload);
@@ -531,8 +534,9 @@ function decodeOrderResponse(
 		for (const cmd of commands) {
 			results.set(cmd.id, "applied");
 			errorCodes.set(cmd.id, null);
+			errorMessages.set(cmd.id, null);
 		}
-		return { ok: true, results, errorCodes, updatedAt };
+		return { ok: true, results, errorCodes, errorMessages, updatedAt };
 	}
 
 	for (let i = 0; i < length; i++) {
@@ -542,8 +546,10 @@ function decodeOrderResponse(
 		if (cmdId === null) continue;
 		const applied = item.cmdApplied();
 		const errorCode = item.cmdErrorCode();
+		const errorMessage = item.cmdErrorMessage();
 		results.set(cmdId, applied === false ? "rejected" : "applied");
 		errorCodes.set(cmdId, errorCode === null ? null : Number(errorCode));
+		errorMessages.set(cmdId, errorMessage === null ? null : errorMessage);
 	}
 
 	// Defensive: any submitted command not echoed back falls back to
@@ -552,10 +558,11 @@ function decodeOrderResponse(
 		if (!results.has(cmd.id)) {
 			results.set(cmd.id, "applied");
 			errorCodes.set(cmd.id, null);
+			errorMessages.set(cmd.id, null);
 		}
 	}
 
-	return { ok: true, results, errorCodes, updatedAt };
+	return { ok: true, results, errorCodes, errorMessages, updatedAt };
 }
 
 function decodeError(

ui/frontend/tests/helpers/fake-order-client.ts

@@ -174,11 +174,25 @@ export function recordingClient(
  * decode a realistic payload without standing up a full mock
  * gateway.
  */
+/**
+ * FakeFetchStatus carries the per-command result fields the engine
+ * would echo on `user.games.order.get` (cmdApplied / cmdErrorCode /
+ * cmdErrorMessage). The helper omits each set only when the
+ * corresponding pointer is `undefined`, mimicking the engine's
+ * `omitempty` semantics.
+ */
+export interface FakeFetchStatus {
+	applied?: boolean;
+	errorCode?: number;
+	errorMessage?: string;
+}
+
 export function fakeFetchClient(
 	gameId: string,
 	commands: OrderCommand[],
 	updatedAt: number,
 	found = true,
+	statuses?: Record<string, FakeFetchStatus>,
 ): { client: GalaxyClient } {
 	const client: GalaxyClient = {
 		async executeCommand(messageType: string) {
@@ -187,7 +201,7 @@ export function fakeFetchClient(
 			}
 			return {
 				resultCode: "ok",
-				payloadBytes: encodeOrderGet(gameId, commands, updatedAt, found),
+				payloadBytes: encodeOrderGet(gameId, commands, updatedAt, found, statuses ?? {}),
 			};
 		},
 	} as unknown as GalaxyClient;
@@ -200,6 +214,10 @@ function encodeApplied(
 	applied: boolean,
 ): Uint8Array {
 	const builder = new Builder(256);
+	// See `encodeOrderGet` — flatbuffers@25 elides `cmd_applied=false`
+	// against its int8 default; mirror the Go transcoder's force-slot
+	// behaviour so the boolean survives the round trip in tests.
+	builder.forceDefaults(true);
 	const itemOffsets = cmdIds.map((id) => {
 		const cmdIdOffset = builder.createString(id);
 		const nameOffset = builder.createString("ignored");
@@ -235,8 +253,15 @@ function encodeOrderGet(
 	commands: OrderCommand[],
 	updatedAt: number,
 	found: boolean,
+	statuses: Record<string, FakeFetchStatus>,
 ): Uint8Array {
 	const builder = new Builder(256);
+	// flatbuffers@25 elides fields equal to their generated default; the
+	// Go transcoder works around this via explicit `Slot()` calls.
+	// Mirror that behaviour here so `cmd_applied=false` and
+	// `cmd_error_code=0` round-trip through the helper instead of being
+	// silently dropped.
+	builder.forceDefaults(true);
 
 	let orderOffset = 0;
 	if (found) {
@@ -246,6 +271,11 @@ function encodeOrderGet(
 			}
 			const cmdIdOffset = builder.createString(cmd.id);
 			const nameOffset = builder.createString(cmd.name);
+			const status = statuses[cmd.id] ?? {};
+			const errMsgOffset =
+				status.errorMessage !== undefined
+					? builder.createString(status.errorMessage)
+					: 0;
 			const inner = CommandPlanetRename.createCommandPlanetRename(
 				builder,
 				BigInt(cmd.planetNumber),
@@ -253,8 +283,17 @@ function encodeOrderGet(
 			);
 			CommandItem.startCommandItem(builder);
 			CommandItem.addCmdId(builder, cmdIdOffset);
+			if (status.applied !== undefined) {
+				CommandItem.addCmdApplied(builder, status.applied);
+			}
+			if (status.errorCode !== undefined) {
+				CommandItem.addCmdErrorCode(builder, BigInt(status.errorCode));
+			}
 			CommandItem.addPayloadType(builder, CommandPayload.CommandPlanetRename);
 			CommandItem.addPayload(builder, inner);
+			if (errMsgOffset !== 0) {
+				CommandItem.addCmdErrorMessage(builder, errMsgOffset);
+			}
 			return CommandItem.endCommandItem(builder);
 		});
 		const commandsVec = UserGamesOrder.createCommandsVector(builder, itemOffsets);

ui/frontend/tests/order-draft.test.ts

@@ -10,12 +10,13 @@
 import "@testing-library/jest-dom/vitest";
 import "fake-indexeddb/auto";
 import { waitFor } from "@testing-library/svelte";
-import { afterEach, beforeEach, describe, expect, test } from "vitest";
+import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
 import type { IDBPDatabase } from "idb";
 
 import { IDBCache } from "../src/platform/store/idb-cache";
 import { openGalaxyDB, type GalaxyDB } from "../src/platform/store/idb";
 import type { Cache } from "../src/platform/store/index";
+import type { GalaxyClient } from "../src/api/galaxy-client";
 import { OrderDraftStore } from "../src/sync/order-draft.svelte";
 import type { OrderCommand } from "../src/sync/order-types";
 
@@ -448,6 +449,51 @@ describe("OrderDraftStore", () => {
 		store.dispose();
 	});
 
+	test("hydrateFromServer preserves per-command rejected status and error message", async () => {
+		const { fakeFetchClient } = await import("./helpers/fake-order-client");
+		const { client } = fakeFetchClient(
+			GAME_ID,
+			[
+				{
+					kind: "planetRename",
+					id: "ok-1",
+					planetNumber: 7,
+					name: "OkTown",
+				},
+				{
+					kind: "planetRename",
+					id: "bad-1",
+					planetNumber: 8,
+					name: "Doomed",
+				},
+			],
+			42,
+			true,
+			{
+				"ok-1": { applied: true, errorCode: 0 },
+				"bad-1": {
+					applied: false,
+					errorCode: 3003,
+					errorMessage: 'Entity does not exists: planet #99',
+				},
+			},
+		);
+
+		const store = new OrderDraftStore();
+		await store.init({ cache, gameId: GAME_ID });
+		await store.hydrateFromServer({ client, turn: 5 });
+
+		expect(store.commands).toHaveLength(2);
+		expect(store.statuses["ok-1"]).toBe("applied");
+		expect(store.statuses["bad-1"]).toBe("rejected");
+		expect(store.errorMessages["ok-1"]).toBeUndefined();
+		expect(store.errorMessages["bad-1"]).toBe(
+			"Entity does not exists: planet #99",
+		);
+		expect(store.syncStatus).toBe("synced");
+		store.dispose();
+	});
+
 	test("hydrate empties the local cache when server returns found=false", async () => {
 		// First seed a local draft.
 		const seeded = new OrderDraftStore();
@@ -555,6 +601,85 @@ describe("OrderDraftStore auto-sync", () => {
 		store.dispose();
 	});
 
+	test("per-command rejection in a successful response keeps syncStatus 'synced'", async () => {
+		// Per-command rejection means the round trip succeeded — only
+		// individual commands were rejected by the in-game rules — so
+		// the sync bar must stay green. A blanket `syncStatus = "error"`
+		// + Retry button only fits genuine transport / engine failures.
+		const { Builder } = await import("flatbuffers");
+		const fbs = await import("../src/proto/galaxy/fbs/order");
+		const common = await import("../src/proto/galaxy/fbs/common");
+		const { uuidToHiLo } = await import("../src/api/game-state");
+
+		const cmd = {
+			kind: "planetRename" as const,
+			id: "rej-1",
+			planetNumber: 9,
+			name: "Doomed",
+		};
+
+		const exec = vi.fn(async () => {
+			const builder = new Builder(256);
+			builder.forceDefaults(true);
+			const cmdIdOffset = builder.createString(cmd.id);
+			const nameOffset = builder.createString("ignored");
+			const errMsg = builder.createString(
+				"Entity does not exists: planet #99",
+			);
+			const inner = fbs.CommandPlanetRename.createCommandPlanetRename(
+				builder,
+				BigInt(0),
+				nameOffset,
+			);
+			fbs.CommandItem.startCommandItem(builder);
+			fbs.CommandItem.addCmdId(builder, cmdIdOffset);
+			fbs.CommandItem.addCmdApplied(builder, false);
+			fbs.CommandItem.addCmdErrorCode(builder, BigInt(3003));
+			fbs.CommandItem.addPayloadType(
+				builder,
+				fbs.CommandPayload.CommandPlanetRename,
+			);
+			fbs.CommandItem.addPayload(builder, inner);
+			fbs.CommandItem.addCmdErrorMessage(builder, errMsg);
+			const item = fbs.CommandItem.endCommandItem(builder);
+			const commandsVec = fbs.UserGamesOrderResponse.createCommandsVector(
+				builder,
+				[item],
+			);
+			const [hi, lo] = uuidToHiLo(GAME_ID);
+			const gameIdOffset = common.UUID.createUUID(builder, hi, lo);
+			fbs.UserGamesOrderResponse.startUserGamesOrderResponse(builder);
+			fbs.UserGamesOrderResponse.addGameId(builder, gameIdOffset);
+			fbs.UserGamesOrderResponse.addUpdatedAt(builder, BigInt(99));
+			fbs.UserGamesOrderResponse.addCommands(builder, commandsVec);
+			const offset = fbs.UserGamesOrderResponse.endUserGamesOrderResponse(
+				builder,
+			);
+			builder.finish(offset);
+			return {
+				resultCode: "ok",
+				payloadBytes: builder.asUint8Array(),
+			};
+		});
+		const client = { executeCommand: exec } as unknown as GalaxyClient;
+
+		const store = new OrderDraftStore();
+		await store.init({ cache, gameId: GAME_ID });
+		store.bindClient(client);
+		await store.add(cmd);
+		await waitFor(() => {
+			expect(exec).toHaveBeenCalled();
+			expect(store.statuses[cmd.id]).toBe("rejected");
+		});
+
+		expect(store.syncStatus).toBe("synced");
+		expect(store.syncError).toBeNull();
+		expect(store.errorMessages[cmd.id]).toBe(
+			"Entity does not exists: planet #99",
+		);
+		store.dispose();
+	});
+
 	test("non-ok response marks every in-flight command as rejected", async () => {
 		const { recordingClient } = await import("./helpers/fake-order-client");
 		const handle = recordingClient(GAME_ID, "rejected");

ui/frontend/tests/order-queue.test.ts

@@ -69,6 +69,7 @@ function success(updatedAt = 1): SubmitSuccess {
 		ok: true,
 		results: new Map([["id", "applied"]]),
 		errorCodes: new Map([["id", null]]),
+		errorMessages: new Map([["id", null]]),
 		updatedAt,
 	};
 }

ui/frontend/tests/submit.test.ts

@@ -40,13 +40,28 @@ function mockClient(
 }
 
 function buildResponse(
-	commands: { id: string; applied: boolean | null; errorCode: number | null }[],
+	commands: {
+		id: string;
+		applied: boolean | null;
+		errorCode: number | null;
+		errorMessage?: string | null;
+	}[],
 	updatedAt: number,
 ): Uint8Array {
 	const builder = new Builder(256);
+	// flatbuffers@25 skips fields equal to their generated default when
+	// writing — the Go transcoder works around this via explicit
+	// `Slot()` calls. This fixture stands in for the engine + gateway,
+	// so we flip `forceDefaults` to keep `cmd_applied=false` (=== int8
+	// default 0) and `cmd_error_code=0` from being silently elided.
+	builder.forceDefaults(true);
 	const itemOffsets = commands.map((c) => {
 		const cmdIdOffset = builder.createString(c.id);
 		const nameOffset = builder.createString("ignored");
+		const errMsgOffset =
+			c.errorMessage !== undefined && c.errorMessage !== null
+				? builder.createString(c.errorMessage)
+				: 0;
 		const payloadOffset = CommandPlanetRename.createCommandPlanetRename(
 			builder,
 			BigInt(0),
@@ -60,6 +75,9 @@ function buildResponse(
 		}
 		CommandItem.addPayloadType(builder, CommandPayload.CommandPlanetRename);
 		CommandItem.addPayload(builder, payloadOffset);
+		if (errMsgOffset !== 0) {
+			CommandItem.addCmdErrorMessage(builder, errMsgOffset);
+		}
 		return CommandItem.endCommandItem(builder);
 	});
 	const commandsVec = UserGamesOrderResponse.createCommandsVector(builder, itemOffsets);