fix(order): surface rejection reason, keep sync green, hydrate verdicts

Three issues surfaced once the per-command rejection from the previous
commit actually reached the UI:

1. Sync banner falsely red. `OrderDraftStore.runSync` flipped
   `syncStatus = "error"` whenever any command was rejected and
   advertised a Retry button. A per-command rejection is a
   player-correctable state — the round trip succeeded, the engine
   just refused that command — so the retry can't help. Keep
   `syncStatus = "synced"` on `success`; the red row highlight is
   the visible cue.

2. Rejection reason missing. Add `cmd_error_message: string` to
   `CommandItem` in `pkg/schema/fbs/order.fbs` (appended last to
   preserve existing slot offsets) and regenerate the Go + TS stubs
   for that one type. Plumb the message through `CommandMeta`,
   `Controller.applyCommand`'s `m.Result(code, message)` call, the
   Go transcoder, the UI decoders in `submit.ts` /  `order-load.ts`,
   and the `OrderDraftStore.errorMessages` map. `order-tab.svelte`
   renders it as an italic danger-coloured line under rejected
   commands, with new CSS for `.error-reason`.

3. Verdict lost on navigation. `order-load.ts.decodeCommand` never
   read `cmdApplied`/`cmdErrorCode`, so `hydrateFromServer` fell
   back to a blanket "applied" status — a previously-rejected
   command came back green after a lobby → game round trip. Extend
   the fetch decoder to populate `statuses`/`errorCodes`/
   `errorMessages` maps and have `hydrateFromServer` use them.
   Engine-side persistence already records the verdict on disk —
   verified against the live `0000/order/<id>.json`.

`flatbuffers@25` elides default-int8/int64 fields on write; the Go
transcoder force-slots `cmd_applied=false` / `cmd_error_code=0`
already, the new test fixtures flip `builder.forceDefaults(true)` to
mirror that behaviour so the round trip survives.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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(