diff --git a/frontend/history-ui/src/lib/types/ClientCursors.ts b/frontend/history-ui/src/lib/types/ClientCursors.ts
index 14298431..bb629100 100644
--- a/frontend/history-ui/src/lib/types/ClientCursors.ts
+++ b/frontend/history-ui/src/lib/types/ClientCursors.ts
@@ -1,8 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { DocumentWithCursors } from "./DocumentWithCursors";
 
-export type ClientCursors = {
-    userName: string;
-    deviceId: string;
-    documentsWithCursors: Array<DocumentWithCursors>;
-};
+export type ClientCursors = { userName: string, deviceId: string, documentsWithCursors: Array<DocumentWithCursors>, };
diff --git a/frontend/history-ui/src/lib/types/CreateDocumentVersion.ts b/frontend/history-ui/src/lib/types/CreateDocumentVersion.ts
index 389d8e88..29d3f55e 100644
--- a/frontend/history-ui/src/lib/types/CreateDocumentVersion.ts
+++ b/frontend/history-ui/src/lib/types/CreateDocumentVersion.ts
@@ -1,7 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export type CreateDocumentVersion = {
-    relative_path: string;
-    last_seen_vault_update_id: number;
-    content: Array<number>;
-};
+export type CreateDocumentVersion = { relative_path: string, last_seen_vault_update_id: number, content: Array<number>, };
diff --git a/frontend/history-ui/src/lib/types/CursorPositionFromClient.ts b/frontend/history-ui/src/lib/types/CursorPositionFromClient.ts
index 5846843e..60b48e5e 100644
--- a/frontend/history-ui/src/lib/types/CursorPositionFromClient.ts
+++ b/frontend/history-ui/src/lib/types/CursorPositionFromClient.ts
@@ -1,6 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { DocumentWithCursors } from "./DocumentWithCursors";
 
-export type CursorPositionFromClient = {
-    documentsWithCursors: Array<DocumentWithCursors>;
-};
+export type CursorPositionFromClient = { documentsWithCursors: Array<DocumentWithCursors>, };
diff --git a/frontend/history-ui/src/lib/types/CursorPositionFromServer.ts b/frontend/history-ui/src/lib/types/CursorPositionFromServer.ts
index 3a72c706..c8444892 100644
--- a/frontend/history-ui/src/lib/types/CursorPositionFromServer.ts
+++ b/frontend/history-ui/src/lib/types/CursorPositionFromServer.ts
@@ -1,4 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { ClientCursors } from "./ClientCursors";
 
-export type CursorPositionFromServer = { clients: Array<ClientCursors> };
+export type CursorPositionFromServer = { clients: Array<ClientCursors>, };
diff --git a/frontend/history-ui/src/lib/types/CursorSpan.ts b/frontend/history-ui/src/lib/types/CursorSpan.ts
index 916019ce..d0bce6ea 100644
--- a/frontend/history-ui/src/lib/types/CursorSpan.ts
+++ b/frontend/history-ui/src/lib/types/CursorSpan.ts
@@ -1,3 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export type CursorSpan = { start: number; end: number };
+export type CursorSpan = { start: number, end: number, };
diff --git a/frontend/history-ui/src/lib/types/DocumentUpdateResponse.ts b/frontend/history-ui/src/lib/types/DocumentUpdateResponse.ts
index dd7eadda..51e0b37c 100644
--- a/frontend/history-ui/src/lib/types/DocumentUpdateResponse.ts
+++ b/frontend/history-ui/src/lib/types/DocumentUpdateResponse.ts
@@ -5,6 +5,4 @@ import type { DocumentVersionWithoutContent } from "./DocumentVersionWithoutCont
 /**
  * Response to a create/update document request.
  */
-export type DocumentUpdateResponse =
-    | ({ type: "FastForwardUpdate" } & DocumentVersionWithoutContent)
-    | ({ type: "MergingUpdate" } & DocumentVersion);
+export type DocumentUpdateResponse = { "type": "FastForwardUpdate" } & DocumentVersionWithoutContent | { "type": "MergingUpdate" } & DocumentVersion;
diff --git a/frontend/history-ui/src/lib/types/DocumentVersion.ts b/frontend/history-ui/src/lib/types/DocumentVersion.ts
index 50a6c591..37bd32ca 100644
--- a/frontend/history-ui/src/lib/types/DocumentVersion.ts
+++ b/frontend/history-ui/src/lib/types/DocumentVersion.ts
@@ -1,12 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export type DocumentVersion = {
-    vaultUpdateId: number;
-    documentId: string;
-    relativePath: string;
-    updatedDate: string;
-    contentBase64: string;
-    isDeleted: boolean;
-    userId: string;
-    deviceId: string;
-};
+export type DocumentVersion = { vaultUpdateId: number, documentId: string, relativePath: string, updatedDate: string, contentBase64: string, isDeleted: boolean, userId: string, deviceId: string, };
diff --git a/frontend/history-ui/src/lib/types/DocumentVersionWithoutContent.ts b/frontend/history-ui/src/lib/types/DocumentVersionWithoutContent.ts
index dad1f135..18d9bca5 100644
--- a/frontend/history-ui/src/lib/types/DocumentVersionWithoutContent.ts
+++ b/frontend/history-ui/src/lib/types/DocumentVersionWithoutContent.ts
@@ -1,12 +1,7 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export type DocumentVersionWithoutContent = {
-    vaultUpdateId: number;
-    documentId: string;
-    relativePath: string;
-    updatedDate: string;
-    isDeleted: boolean;
-    userId: string;
-    deviceId: string;
-    contentSize: number;
-};
+export type DocumentVersionWithoutContent = { vaultUpdateId: number, documentId: string, relativePath: string, updatedDate: string, isDeleted: boolean, userId: string, deviceId: string, contentSize: number, 
+/**
+ * True iff this is the first version of the document
+ */
+isNewFile: boolean, };
diff --git a/frontend/history-ui/src/lib/types/DocumentWithCursors.ts b/frontend/history-ui/src/lib/types/DocumentWithCursors.ts
index ca6a2155..3504ce33 100644
--- a/frontend/history-ui/src/lib/types/DocumentWithCursors.ts
+++ b/frontend/history-ui/src/lib/types/DocumentWithCursors.ts
@@ -1,9 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { CursorSpan } from "./CursorSpan";
 
-export type DocumentWithCursors = {
-    vaultUpdateId: number | null;
-    documentId: string;
-    relativePath: string;
-    cursors: Array<CursorSpan>;
-};
+export type DocumentWithCursors = { vaultUpdateId: number | null, documentId: string, relativePath: string, cursors: Array<CursorSpan>, };
diff --git a/frontend/history-ui/src/lib/types/FetchLatestDocumentsResponse.ts b/frontend/history-ui/src/lib/types/FetchLatestDocumentsResponse.ts
index 141c2565..ce572684 100644
--- a/frontend/history-ui/src/lib/types/FetchLatestDocumentsResponse.ts
+++ b/frontend/history-ui/src/lib/types/FetchLatestDocumentsResponse.ts
@@ -4,10 +4,8 @@ import type { DocumentVersionWithoutContent } from "./DocumentVersionWithoutCont
 /**
  * Response to a fetch latest documents request.
  */
-export type FetchLatestDocumentsResponse = {
-    latestDocuments: Array<DocumentVersionWithoutContent>;
-    /**
-     * The update ID of the latest document in the response.
-     */
-    lastUpdateId: bigint;
-};
+export type FetchLatestDocumentsResponse = { latestDocuments: Array<DocumentVersionWithoutContent>, 
+/**
+ * The update ID of the latest document in the response.
+ */
+lastUpdateId: bigint, };
diff --git a/frontend/history-ui/src/lib/types/ListVaultsResponse.ts b/frontend/history-ui/src/lib/types/ListVaultsResponse.ts
index 604ad958..92b2b3e0 100644
--- a/frontend/history-ui/src/lib/types/ListVaultsResponse.ts
+++ b/frontend/history-ui/src/lib/types/ListVaultsResponse.ts
@@ -4,8 +4,4 @@ import type { VaultInfo } from "./VaultInfo";
 /**
  * Response to listing vaults accessible to the authenticated user.
  */
-export type ListVaultsResponse = {
-    vaults: Array<VaultInfo>;
-    hasMore: boolean;
-    userName: string;
-};
+export type ListVaultsResponse = { vaults: Array<VaultInfo>, hasMore: boolean, userName: string, };
diff --git a/frontend/history-ui/src/lib/types/PingResponse.ts b/frontend/history-ui/src/lib/types/PingResponse.ts
index 7e5ac4f8..c38845d2 100644
--- a/frontend/history-ui/src/lib/types/PingResponse.ts
+++ b/frontend/history-ui/src/lib/types/PingResponse.ts
@@ -3,23 +3,22 @@
 /**
  * Response to a ping request.
  */
-export type PingResponse = {
-    /**
-     * Semantic version of the server.
-     */
-    serverVersion: string;
-    /**
-     * Whether the client is authenticated based on the sent Authorization
-     * header.
-     */
-    isAuthenticated: boolean;
-    /**
-     * List of file extensions that are allowed to be merged.
-     */
-    mergeableFileExtensions: Array<string>;
-    /**
-     * API version ensuring backwards & forwards compatibility between the client
-     * and server.
-     */
-    supportedApiVersion: number;
-};
+export type PingResponse = { 
+/**
+ * Semantic version of the server.
+ */
+serverVersion: string, 
+/**
+ * Whether the client is authenticated based on the sent Authorization
+ * header.
+ */
+isAuthenticated: boolean, 
+/**
+ * List of file extensions that are allowed to be merged.
+ */
+mergeableFileExtensions: Array<string>, 
+/**
+ * API version ensuring backwards & forwards compatibility between the client
+ * and server.
+ */
+supportedApiVersion: number, };
diff --git a/frontend/history-ui/src/lib/types/SerializedError.ts b/frontend/history-ui/src/lib/types/SerializedError.ts
index 354305f6..5e3fa9b9 100644
--- a/frontend/history-ui/src/lib/types/SerializedError.ts
+++ b/frontend/history-ui/src/lib/types/SerializedError.ts
@@ -1,7 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export type SerializedError = {
-    errorType: string;
-    message: string;
-    causes: Array<string>;
-};
+export type SerializedError = { errorType: string, message: string, causes: Array<string>, };
diff --git a/frontend/history-ui/src/lib/types/UpdateTextDocumentVersion.ts b/frontend/history-ui/src/lib/types/UpdateTextDocumentVersion.ts
index ce0272e3..1c86b132 100644
--- a/frontend/history-ui/src/lib/types/UpdateTextDocumentVersion.ts
+++ b/frontend/history-ui/src/lib/types/UpdateTextDocumentVersion.ts
@@ -1,7 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export type UpdateTextDocumentVersion = {
-    parentVersionId: number;
-    relativePath: string;
-    content: Array<number | string>;
-};
+export type UpdateTextDocumentVersion = { parentVersionId: number, relativePath: string | null, content: Array<number | string>, };
diff --git a/frontend/history-ui/src/lib/types/VaultHistoryResponse.ts b/frontend/history-ui/src/lib/types/VaultHistoryResponse.ts
index e69366f0..ae91b480 100644
--- a/frontend/history-ui/src/lib/types/VaultHistoryResponse.ts
+++ b/frontend/history-ui/src/lib/types/VaultHistoryResponse.ts
@@ -4,7 +4,4 @@ import type { DocumentVersionWithoutContent } from "./DocumentVersionWithoutCont
 /**
  * Response to a vault history request (paginated).
  */
-export type VaultHistoryResponse = {
-    versions: Array<DocumentVersionWithoutContent>;
-    hasMore: boolean;
-};
+export type VaultHistoryResponse = { versions: Array<DocumentVersionWithoutContent>, hasMore: boolean, };
diff --git a/frontend/history-ui/src/lib/types/VaultInfo.ts b/frontend/history-ui/src/lib/types/VaultInfo.ts
index 3f630ae9..32373346 100644
--- a/frontend/history-ui/src/lib/types/VaultInfo.ts
+++ b/frontend/history-ui/src/lib/types/VaultInfo.ts
@@ -3,8 +3,4 @@
 /**
  * Summary of a single vault returned by the list-vaults endpoint.
  */
-export type VaultInfo = {
-    name: string;
-    documentCount: number;
-    createdAt: string | null;
-};
+export type VaultInfo = { name: string, documentCount: number, createdAt: string | null, };
diff --git a/frontend/history-ui/src/lib/types/WebSocketClientMessage.ts b/frontend/history-ui/src/lib/types/WebSocketClientMessage.ts
index 9608f3af..5765a0d0 100644
--- a/frontend/history-ui/src/lib/types/WebSocketClientMessage.ts
+++ b/frontend/history-ui/src/lib/types/WebSocketClientMessage.ts
@@ -2,6 +2,4 @@
 import type { CursorPositionFromClient } from "./CursorPositionFromClient";
 import type { WebSocketHandshake } from "./WebSocketHandshake";
 
-export type WebSocketClientMessage =
-    | ({ type: "handshake" } & WebSocketHandshake)
-    | ({ type: "cursorPositions" } & CursorPositionFromClient);
+export type WebSocketClientMessage = { "type": "handshake" } & WebSocketHandshake | { "type": "cursorPositions" } & CursorPositionFromClient;
diff --git a/frontend/history-ui/src/lib/types/WebSocketHandshake.ts b/frontend/history-ui/src/lib/types/WebSocketHandshake.ts
index 8e51a121..85c2cf0d 100644
--- a/frontend/history-ui/src/lib/types/WebSocketHandshake.ts
+++ b/frontend/history-ui/src/lib/types/WebSocketHandshake.ts
@@ -1,7 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export type WebSocketHandshake = {
-    token: string;
-    deviceId: string;
-    lastSeenVaultUpdateId: number | null;
-};
+export type WebSocketHandshake = { token: string, deviceId: string, lastSeenVaultUpdateId: number | null, };
diff --git a/frontend/history-ui/src/lib/types/WebSocketServerMessage.ts b/frontend/history-ui/src/lib/types/WebSocketServerMessage.ts
index fd250b7b..45e37358 100644
--- a/frontend/history-ui/src/lib/types/WebSocketServerMessage.ts
+++ b/frontend/history-ui/src/lib/types/WebSocketServerMessage.ts
@@ -2,6 +2,4 @@
 import type { CursorPositionFromServer } from "./CursorPositionFromServer";
 import type { WebSocketVaultUpdate } from "./WebSocketVaultUpdate";
 
-export type WebSocketServerMessage =
-    | ({ type: "vaultUpdate" } & WebSocketVaultUpdate)
-    | ({ type: "cursorPositions" } & CursorPositionFromServer);
+export type WebSocketServerMessage = { "type": "vaultUpdate" } & WebSocketVaultUpdate | { "type": "cursorPositions" } & CursorPositionFromServer;
diff --git a/frontend/history-ui/src/lib/types/WebSocketVaultUpdate.ts b/frontend/history-ui/src/lib/types/WebSocketVaultUpdate.ts
index 94d70c0a..fc10827f 100644
--- a/frontend/history-ui/src/lib/types/WebSocketVaultUpdate.ts
+++ b/frontend/history-ui/src/lib/types/WebSocketVaultUpdate.ts
@@ -1,4 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { DocumentVersionWithoutContent } from "./DocumentVersionWithoutContent";
 
-export type WebSocketVaultUpdate = { document: DocumentVersionWithoutContent };
+export type WebSocketVaultUpdate = { document: DocumentVersionWithoutContent, };
diff --git a/frontend/sync-client/src/file-operations/file-operations.ts b/frontend/sync-client/src/file-operations/file-operations.ts
index 098e86f4..84826c65 100644
--- a/frontend/sync-client/src/file-operations/file-operations.ts
+++ b/frontend/sync-client/src/file-operations/file-operations.ts
@@ -16,6 +16,20 @@ export enum MoveOnConflict {
     NEW = "NEW"
 }
 
+/**
+ * Outcome of a `move`/`create`. `actualPath` is where the new file
+ * ended up (which may differ from the requested path under
+ * `MoveOnConflict.NEW` if the target was occupied). `displacedTo` is
+ * set only when an existing file at the requested path was bumped to
+ * a `conflict-…` path under `MoveOnConflict.EXISTING`; the caller
+ * uses it to repoint any tracking for the displaced doc before its
+ * own follow-up `setDocument` clobbers the old slot.
+ */
+export interface FileOpResult {
+    actualPath: RelativePath;
+    displacedTo?: RelativePath;
+}
+
 export class FileOperations {
     private readonly fs: SafeFileSystemOperations;
 
@@ -67,29 +81,27 @@ export class FileOperations {
      *
      * If a file with the same name already exists, it is moved before creating the new one.
      * Parent directories are created if necessary.
-     *
-     * Returns the actual path the file was created at.
      */
     public async create(
         path: RelativePath,
         newContent: Uint8Array,
         moveOnConflict: MoveOnConflict
-    ): Promise<RelativePath> {
-        const actualPath = await this.ensureClearPath(path, moveOnConflict);
+    ): Promise<FileOpResult> {
+        const result = await this.ensureClearPath(path, moveOnConflict);
         // ensureClearPath leaves actualPath empty: either the file never
         // existed, or it was just renamed away. The upcoming write therefore
         // looks like a fresh create to the watcher.
-        this.expectedFsEvents.expectCreate(actualPath);
+        this.expectedFsEvents.expectCreate(result.actualPath);
         try {
             await this.fs.write(
-                actualPath,
+                result.actualPath,
                 this.toNativeLineEndings(newContent)
             );
         } catch (e) {
-            this.expectedFsEvents.unexpectCreate(actualPath);
+            this.expectedFsEvents.unexpectCreate(result.actualPath);
             throw e;
         }
-        return actualPath;
+        return result;
     }
 
     /**
@@ -215,37 +227,36 @@ export class FileOperations {
 
 
 
-    // Returns the actual path the file got moved to.
     public async move(
         oldPath: RelativePath,
         newPath: RelativePath,
         moveOnConflict: MoveOnConflict
-    ): Promise<RelativePath> {
+    ): Promise<FileOpResult> {
         if (oldPath === newPath) {
-            return oldPath;
+            return { actualPath: oldPath };
         }
 
-        const actualPath = await this.ensureClearPath(newPath, moveOnConflict);
-        this.expectedFsEvents.expectRename(oldPath, actualPath);
+        const cleared = await this.ensureClearPath(newPath, moveOnConflict);
+        this.expectedFsEvents.expectRename(oldPath, cleared.actualPath);
         try {
-            await this.fs.rename(oldPath, actualPath);
+            await this.fs.rename(oldPath, cleared.actualPath);
         } catch (e) {
-            this.expectedFsEvents.unexpectRename(oldPath, actualPath);
+            this.expectedFsEvents.unexpectRename(oldPath, cleared.actualPath);
             throw e;
         }
         await this.deletingEmptyParentDirectoriesOfDeletedFile(oldPath);
-        return actualPath;
+        return cleared;
     }
 
     private async ensureClearPath(
         path: RelativePath,
         moveOnConflict: MoveOnConflict
-    ): Promise<RelativePath> {
+    ): Promise<FileOpResult> {
         if (await this.fs.exists(path)) {
             const conflictPath = FileOperations.buildConflictPath(path);
 
             if (moveOnConflict === MoveOnConflict.NEW) {
-                return conflictPath;
+                return { actualPath: conflictPath };
             }
 
             this.logger.debug(
@@ -266,7 +277,7 @@ export class FileOperations {
             `No existing file at ${path}, creating parent directories if needed`
         );
         await this.createParentDirectories(path);
-        return path;
+        return { actualPath: path };
     }
 
     private async deletingEmptyParentDirectoriesOfDeletedFile(
diff --git a/frontend/sync-client/src/services/sync-service.ts b/frontend/sync-client/src/services/sync-service.ts
index 40afc709..47aea2f4 100644
--- a/frontend/sync-client/src/services/sync-service.ts
+++ b/frontend/sync-client/src/services/sync-service.ts
@@ -71,7 +71,7 @@ export class SyncService {
         response: Response,
         operation: string
     ): Promise<void> {
-        if (response.ok) {return;}
+        if (response.ok) { return; }
         const message = `Failed to ${operation}: ${await SyncService.errorFromResponse(response)}`;
         // 429 is the only 4xx the server uses for *transient* contention
         // (`WriteBusyError` → HTTP 429). Every other 4xx means the request
@@ -154,17 +154,17 @@ export class SyncService {
     }: {
         parentVersionId: VaultUpdateId;
         documentId: DocumentId;
-        relativePath: RelativePath;
+        relativePath: RelativePath | undefined;
         content: (number | string)[];
     }): Promise<DocumentUpdateResponse> {
         return this.retryForever(async () => {
             this.logger.debug(
-                `Updating text document ${documentId} with parent version ${parentVersionId} and relative path ${relativePath}, content [${content.join(", ")}]`
+                `Updating text document ${documentId} with parent version ${parentVersionId} and relative path ${relativePath ?? "<unchanged>"}, content [${content.join(", ")}]`
             );
 
             const request: UpdateTextDocumentVersion = {
                 parentVersionId,
-                relativePath,
+                relativePath: relativePath ?? null,
                 content
             };
 
@@ -199,16 +199,18 @@ export class SyncService {
     }: {
         parentVersionId: VaultUpdateId;
         documentId: DocumentId;
-        relativePath: RelativePath;
+        relativePath: RelativePath | undefined;
         contentBytes: Uint8Array;
     }): Promise<DocumentUpdateResponse> {
         return this.retryForever(async () => {
             this.logger.debug(
-                `Updating binary document ${documentId} with parent version ${parentVersionId} and relative path ${relativePath}`
+                `Updating binary document ${documentId} with parent version ${parentVersionId} and relative path ${relativePath ?? "<unchanged>"}`
             );
             const formData = new FormData();
             formData.append("parent_version_id", parentVersionId.toString());
-            formData.append("relative_path", relativePath);
+            if (relativePath !== undefined) {
+                formData.append("relative_path", relativePath);
+            }
             formData.append(
                 "content",
                 new Blob([new Uint8Array(contentBytes)])
@@ -239,14 +241,12 @@ export class SyncService {
 
     public async delete({
         documentId,
-        relativePath
     }: {
         documentId: DocumentId;
-        relativePath: RelativePath;
     }): Promise<DocumentVersionWithoutContent> {
         return this.retryForever(async () => {
             this.logger.debug(
-                `Delete document with id ${documentId} and relative path ${relativePath}`
+                `Delete document with id ${documentId}`
             );
 
             // The server identifies the document by its URL path; no body
@@ -265,7 +265,7 @@ export class SyncService {
                 (await response.json()) as DocumentVersionWithoutContent; // eslint-disable-line @typescript-eslint/no-unsafe-type-assertion
 
             this.logger.debug(
-                `Deleted document ${relativePath} with id ${documentId}`
+                `Deleted document with id ${documentId}`
             );
 
             return result;
diff --git a/frontend/sync-client/src/services/types/ClientCursors.ts b/frontend/sync-client/src/services/types/ClientCursors.ts
index e8c9b93d..5b1ec040 100644
--- a/frontend/sync-client/src/services/types/ClientCursors.ts
+++ b/frontend/sync-client/src/services/types/ClientCursors.ts
@@ -1,8 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { DocumentWithCursors } from "./DocumentWithCursors";
 
-export interface ClientCursors {
-    userName: string;
-    deviceId: string;
-    documentsWithCursors: DocumentWithCursors[];
-}
+export interface ClientCursors { userName: string, deviceId: string, documentsWithCursors: DocumentWithCursors[], }
diff --git a/frontend/sync-client/src/services/types/CreateDocumentVersion.ts b/frontend/sync-client/src/services/types/CreateDocumentVersion.ts
index 2d83cd99..4d1b324e 100644
--- a/frontend/sync-client/src/services/types/CreateDocumentVersion.ts
+++ b/frontend/sync-client/src/services/types/CreateDocumentVersion.ts
@@ -1,7 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export interface CreateDocumentVersion {
-    relative_path: string;
-    last_seen_vault_update_id: number;
-    content: number[];
-}
+export interface CreateDocumentVersion { relative_path: string, last_seen_vault_update_id: number, content: number[], }
diff --git a/frontend/sync-client/src/services/types/CursorPositionFromClient.ts b/frontend/sync-client/src/services/types/CursorPositionFromClient.ts
index ee937f4e..78823b5d 100644
--- a/frontend/sync-client/src/services/types/CursorPositionFromClient.ts
+++ b/frontend/sync-client/src/services/types/CursorPositionFromClient.ts
@@ -1,6 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { DocumentWithCursors } from "./DocumentWithCursors";
 
-export interface CursorPositionFromClient {
-    documentsWithCursors: DocumentWithCursors[];
-}
+export interface CursorPositionFromClient { documentsWithCursors: DocumentWithCursors[], }
diff --git a/frontend/sync-client/src/services/types/CursorPositionFromServer.ts b/frontend/sync-client/src/services/types/CursorPositionFromServer.ts
index 52a24f27..ed6ac7b2 100644
--- a/frontend/sync-client/src/services/types/CursorPositionFromServer.ts
+++ b/frontend/sync-client/src/services/types/CursorPositionFromServer.ts
@@ -1,6 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { ClientCursors } from "./ClientCursors";
 
-export interface CursorPositionFromServer {
-    clients: ClientCursors[];
-}
+export interface CursorPositionFromServer { clients: ClientCursors[], }
diff --git a/frontend/sync-client/src/services/types/CursorSpan.ts b/frontend/sync-client/src/services/types/CursorSpan.ts
index 2cc2b7fc..7424067c 100644
--- a/frontend/sync-client/src/services/types/CursorSpan.ts
+++ b/frontend/sync-client/src/services/types/CursorSpan.ts
@@ -1,6 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export interface CursorSpan {
-    start: number;
-    end: number;
-}
+export interface CursorSpan { start: number, end: number, }
diff --git a/frontend/sync-client/src/services/types/DocumentUpdateResponse.ts b/frontend/sync-client/src/services/types/DocumentUpdateResponse.ts
index dd7eadda..51e0b37c 100644
--- a/frontend/sync-client/src/services/types/DocumentUpdateResponse.ts
+++ b/frontend/sync-client/src/services/types/DocumentUpdateResponse.ts
@@ -5,6 +5,4 @@ import type { DocumentVersionWithoutContent } from "./DocumentVersionWithoutCont
 /**
  * Response to a create/update document request.
  */
-export type DocumentUpdateResponse =
-    | ({ type: "FastForwardUpdate" } & DocumentVersionWithoutContent)
-    | ({ type: "MergingUpdate" } & DocumentVersion);
+export type DocumentUpdateResponse = { "type": "FastForwardUpdate" } & DocumentVersionWithoutContent | { "type": "MergingUpdate" } & DocumentVersion;
diff --git a/frontend/sync-client/src/services/types/DocumentVersion.ts b/frontend/sync-client/src/services/types/DocumentVersion.ts
index 3b9aa37b..3d50ae65 100644
--- a/frontend/sync-client/src/services/types/DocumentVersion.ts
+++ b/frontend/sync-client/src/services/types/DocumentVersion.ts
@@ -1,12 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export interface DocumentVersion {
-    vaultUpdateId: number;
-    documentId: string;
-    relativePath: string;
-    updatedDate: string;
-    contentBase64: string;
-    isDeleted: boolean;
-    userId: string;
-    deviceId: string;
-}
+export interface DocumentVersion { vaultUpdateId: number, documentId: string, relativePath: string, updatedDate: string, contentBase64: string, isDeleted: boolean, userId: string, deviceId: string, }
diff --git a/frontend/sync-client/src/services/types/DocumentVersionWithoutContent.ts b/frontend/sync-client/src/services/types/DocumentVersionWithoutContent.ts
index 4b24e7c5..c243e639 100644
--- a/frontend/sync-client/src/services/types/DocumentVersionWithoutContent.ts
+++ b/frontend/sync-client/src/services/types/DocumentVersionWithoutContent.ts
@@ -1,12 +1,7 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export interface DocumentVersionWithoutContent {
-    vaultUpdateId: number;
-    documentId: string;
-    relativePath: string;
-    updatedDate: string;
-    isDeleted: boolean;
-    userId: string;
-    deviceId: string;
-    contentSize: number;
-}
+export interface DocumentVersionWithoutContent { vaultUpdateId: number, documentId: string, relativePath: string, updatedDate: string, isDeleted: boolean, userId: string, deviceId: string, contentSize: number, 
+/**
+ * True iff this is the first version of the document
+ */
+isNewFile: boolean, }
diff --git a/frontend/sync-client/src/services/types/DocumentWithCursors.ts b/frontend/sync-client/src/services/types/DocumentWithCursors.ts
index 8ed59067..d29b3f79 100644
--- a/frontend/sync-client/src/services/types/DocumentWithCursors.ts
+++ b/frontend/sync-client/src/services/types/DocumentWithCursors.ts
@@ -1,9 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { CursorSpan } from "./CursorSpan";
 
-export interface DocumentWithCursors {
-    vaultUpdateId: number | null;
-    documentId: string;
-    relativePath: string;
-    cursors: CursorSpan[];
-}
+export interface DocumentWithCursors { vaultUpdateId: number | null, documentId: string, relativePath: string, cursors: CursorSpan[], }
diff --git a/frontend/sync-client/src/services/types/FetchLatestDocumentsResponse.ts b/frontend/sync-client/src/services/types/FetchLatestDocumentsResponse.ts
index 315d701a..3be625bd 100644
--- a/frontend/sync-client/src/services/types/FetchLatestDocumentsResponse.ts
+++ b/frontend/sync-client/src/services/types/FetchLatestDocumentsResponse.ts
@@ -4,10 +4,8 @@ import type { DocumentVersionWithoutContent } from "./DocumentVersionWithoutCont
 /**
  * Response to a fetch latest documents request.
  */
-export interface FetchLatestDocumentsResponse {
-    latestDocuments: DocumentVersionWithoutContent[];
-    /**
-     * The update ID of the latest document in the response.
-     */
-    lastUpdateId: bigint;
-}
+export interface FetchLatestDocumentsResponse { latestDocuments: DocumentVersionWithoutContent[], 
+/**
+ * The update ID of the latest document in the response.
+ */
+lastUpdateId: bigint, }
diff --git a/frontend/sync-client/src/services/types/ListVaultsResponse.ts b/frontend/sync-client/src/services/types/ListVaultsResponse.ts
index babad2d5..85928d89 100644
--- a/frontend/sync-client/src/services/types/ListVaultsResponse.ts
+++ b/frontend/sync-client/src/services/types/ListVaultsResponse.ts
@@ -4,8 +4,4 @@ import type { VaultInfo } from "./VaultInfo";
 /**
  * Response to listing vaults accessible to the authenticated user.
  */
-export interface ListVaultsResponse {
-    vaults: VaultInfo[];
-    hasMore: boolean;
-    userName: string;
-}
+export interface ListVaultsResponse { vaults: VaultInfo[], hasMore: boolean, userName: string, }
diff --git a/frontend/sync-client/src/services/types/PingResponse.ts b/frontend/sync-client/src/services/types/PingResponse.ts
index f96520e9..ba8ceb48 100644
--- a/frontend/sync-client/src/services/types/PingResponse.ts
+++ b/frontend/sync-client/src/services/types/PingResponse.ts
@@ -3,23 +3,22 @@
 /**
  * Response to a ping request.
  */
-export interface PingResponse {
-    /**
-     * Semantic version of the server.
-     */
-    serverVersion: string;
-    /**
-     * Whether the client is authenticated based on the sent Authorization
-     * header.
-     */
-    isAuthenticated: boolean;
-    /**
-     * List of file extensions that are allowed to be merged.
-     */
-    mergeableFileExtensions: string[];
-    /**
-     * API version ensuring backwards & forwards compatibility between the client
-     * and server.
-     */
-    supportedApiVersion: number;
-}
+export interface PingResponse { 
+/**
+ * Semantic version of the server.
+ */
+serverVersion: string, 
+/**
+ * Whether the client is authenticated based on the sent Authorization
+ * header.
+ */
+isAuthenticated: boolean, 
+/**
+ * List of file extensions that are allowed to be merged.
+ */
+mergeableFileExtensions: string[], 
+/**
+ * API version ensuring backwards & forwards compatibility between the client
+ * and server.
+ */
+supportedApiVersion: number, }
diff --git a/frontend/sync-client/src/services/types/SerializedError.ts b/frontend/sync-client/src/services/types/SerializedError.ts
index ec1c4503..4389289e 100644
--- a/frontend/sync-client/src/services/types/SerializedError.ts
+++ b/frontend/sync-client/src/services/types/SerializedError.ts
@@ -1,7 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export interface SerializedError {
-    errorType: string;
-    message: string;
-    causes: string[];
-}
+export interface SerializedError { errorType: string, message: string, causes: string[], }
diff --git a/frontend/sync-client/src/services/types/UpdateTextDocumentVersion.ts b/frontend/sync-client/src/services/types/UpdateTextDocumentVersion.ts
index 46f36bd0..2fb04b31 100644
--- a/frontend/sync-client/src/services/types/UpdateTextDocumentVersion.ts
+++ b/frontend/sync-client/src/services/types/UpdateTextDocumentVersion.ts
@@ -1,7 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export interface UpdateTextDocumentVersion {
-    parentVersionId: number;
-    relativePath: string;
-    content: (number | string)[];
-}
+export interface UpdateTextDocumentVersion { parentVersionId: number, relativePath: string | null, content: (number | string)[], }
diff --git a/frontend/sync-client/src/services/types/VaultHistoryResponse.ts b/frontend/sync-client/src/services/types/VaultHistoryResponse.ts
index 35531010..93d6ec6c 100644
--- a/frontend/sync-client/src/services/types/VaultHistoryResponse.ts
+++ b/frontend/sync-client/src/services/types/VaultHistoryResponse.ts
@@ -4,7 +4,4 @@ import type { DocumentVersionWithoutContent } from "./DocumentVersionWithoutCont
 /**
  * Response to a vault history request (paginated).
  */
-export interface VaultHistoryResponse {
-    versions: DocumentVersionWithoutContent[];
-    hasMore: boolean;
-}
+export interface VaultHistoryResponse { versions: DocumentVersionWithoutContent[], hasMore: boolean, }
diff --git a/frontend/sync-client/src/services/types/VaultInfo.ts b/frontend/sync-client/src/services/types/VaultInfo.ts
index 20d6811c..921645f3 100644
--- a/frontend/sync-client/src/services/types/VaultInfo.ts
+++ b/frontend/sync-client/src/services/types/VaultInfo.ts
@@ -3,8 +3,4 @@
 /**
  * Summary of a single vault returned by the list-vaults endpoint.
  */
-export interface VaultInfo {
-    name: string;
-    documentCount: number;
-    createdAt: string | null;
-}
+export interface VaultInfo { name: string, documentCount: number, createdAt: string | null, }
diff --git a/frontend/sync-client/src/services/types/WebSocketClientMessage.ts b/frontend/sync-client/src/services/types/WebSocketClientMessage.ts
index 9608f3af..5765a0d0 100644
--- a/frontend/sync-client/src/services/types/WebSocketClientMessage.ts
+++ b/frontend/sync-client/src/services/types/WebSocketClientMessage.ts
@@ -2,6 +2,4 @@
 import type { CursorPositionFromClient } from "./CursorPositionFromClient";
 import type { WebSocketHandshake } from "./WebSocketHandshake";
 
-export type WebSocketClientMessage =
-    | ({ type: "handshake" } & WebSocketHandshake)
-    | ({ type: "cursorPositions" } & CursorPositionFromClient);
+export type WebSocketClientMessage = { "type": "handshake" } & WebSocketHandshake | { "type": "cursorPositions" } & CursorPositionFromClient;
diff --git a/frontend/sync-client/src/services/types/WebSocketHandshake.ts b/frontend/sync-client/src/services/types/WebSocketHandshake.ts
index a2910f49..d25651f9 100644
--- a/frontend/sync-client/src/services/types/WebSocketHandshake.ts
+++ b/frontend/sync-client/src/services/types/WebSocketHandshake.ts
@@ -1,7 +1,3 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export interface WebSocketHandshake {
-    token: string;
-    deviceId: string;
-    lastSeenVaultUpdateId: number | null;
-}
+export interface WebSocketHandshake { token: string, deviceId: string, lastSeenVaultUpdateId: number | null, }
diff --git a/frontend/sync-client/src/services/types/WebSocketServerMessage.ts b/frontend/sync-client/src/services/types/WebSocketServerMessage.ts
index fd250b7b..45e37358 100644
--- a/frontend/sync-client/src/services/types/WebSocketServerMessage.ts
+++ b/frontend/sync-client/src/services/types/WebSocketServerMessage.ts
@@ -2,6 +2,4 @@
 import type { CursorPositionFromServer } from "./CursorPositionFromServer";
 import type { WebSocketVaultUpdate } from "./WebSocketVaultUpdate";
 
-export type WebSocketServerMessage =
-    | ({ type: "vaultUpdate" } & WebSocketVaultUpdate)
-    | ({ type: "cursorPositions" } & CursorPositionFromServer);
+export type WebSocketServerMessage = { "type": "vaultUpdate" } & WebSocketVaultUpdate | { "type": "cursorPositions" } & CursorPositionFromServer;
diff --git a/frontend/sync-client/src/services/types/WebSocketVaultUpdate.ts b/frontend/sync-client/src/services/types/WebSocketVaultUpdate.ts
index b4a942c8..5e7df8a5 100644
--- a/frontend/sync-client/src/services/types/WebSocketVaultUpdate.ts
+++ b/frontend/sync-client/src/services/types/WebSocketVaultUpdate.ts
@@ -1,6 +1,4 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { DocumentVersionWithoutContent } from "./DocumentVersionWithoutContent";
 
-export interface WebSocketVaultUpdate {
-    document: DocumentVersionWithoutContent;
-}
+export interface WebSocketVaultUpdate { document: DocumentVersionWithoutContent, }
diff --git a/frontend/sync-client/src/sync-operations/sync-event-queue.test.ts b/frontend/sync-client/src/sync-operations/sync-event-queue.test.ts
index c1dbce9e..30692681 100644
--- a/frontend/sync-client/src/sync-operations/sync-event-queue.test.ts
+++ b/frontend/sync-client/src/sync-operations/sync-event-queue.test.ts
@@ -30,6 +30,7 @@ function fakeRemoteVersion(
         userId: "user",
         deviceId: "device",
         contentSize: 100,
+        isNewFile: true,
         ...overrides
     };
 }
diff --git a/frontend/sync-client/src/sync-operations/syncer.ts b/frontend/sync-client/src/sync-operations/syncer.ts
index c57c6135..9ccc76c8 100644
--- a/frontend/sync-client/src/sync-operations/syncer.ts
+++ b/frontend/sync-client/src/sync-operations/syncer.ts
@@ -446,19 +446,8 @@ export class Syncer {
     ): Promise<void> {
         const documentId = await event.documentId;
 
-        const doc = this.queue.getDocumentByDocumentId(documentId);
-        if (doc === undefined) {
-            // Already deleted (e.g. a remote delete drained ahead of
-            // this redundant local one). Nothing to do.
-            this.logger.debug(
-                `Skipping local-delete for ${documentId} — doc no longer tracked`
-            );
-            return;
-        }
-
         const response = await this.syncService.delete({
             documentId,
-            relativePath: doc.path
         });
 
         // Don't remove the doc from the queue or advance lastSeenUpdateId
@@ -471,7 +460,7 @@ export class Syncer {
             status: SyncStatus.SUCCESS,
             details: {
                 type: SyncType.DELETE,
-                relativePath: doc.path
+                relativePath: event.path
             },
             message: "Successfully deleted file on the server",
             author: response.userId,
@@ -499,8 +488,21 @@ export class Syncer {
         const contentBytes = await this.operations.read(diskPath);
         const contentHash = await hash(contentBytes);
 
+        // For a user-driven rename the user's intent is `event.originalPath`
+        // — that's the rename target. For a content-only edit the user is
+        // agnostic to the path; sending one would be wrong if a remote
+        // rename processed first, because the server would interpret the
+        // user's (now-stale) path as a rename back. So content-only PUTs
+        // omit the path and the server keeps the doc at its current
+        // server-known location.
+        const renameTarget = event.isUserRename
+            ? event.originalPath
+            : undefined;
+
         const hashChanged = contentHash !== record.remoteHash;
-        const pathChanged = record.remoteRelativePath !== event.originalPath;
+        const pathChanged =
+            renameTarget !== undefined &&
+            record.remoteRelativePath !== renameTarget;
 
         if (!hashChanged && !pathChanged) {
             this.logger.debug(
@@ -511,12 +513,16 @@ export class Syncer {
 
         const response = await this.sendUpdate({
             record,
-            relativePath: event.originalPath,
+            relativePath: renameTarget,
             contentBytes
         });
 
         if (response.isDeleted) {
-            await this.processRemoteDelete(diskPath, { ...response, contentSize: 0 });
+            await this.processRemoteDelete(diskPath, {
+                ...response,
+                contentSize: 0,
+                isNewFile: false
+            });
             return;
         }
 
@@ -716,6 +722,14 @@ export class Syncer {
             );
         }
 
+        if (!remoteVersion.isNewFile) {
+            this.queue.lastSeenUpdateId = remoteVersion.vaultUpdateId;
+            this.logger.debug(
+                `Ignoring stale RemoteChange for untracked, non-new document ${remoteVersion.documentId}`
+            );
+            return;
+        }
+
         return this.processRemoteCreateForNewDocument(remoteVersion);
     }
 
@@ -889,13 +903,15 @@ export class Syncer {
         contentBytes
     }: {
         record: DocumentRecord;
-        relativePath: RelativePath;
+        // `undefined` for content-only edits; the server keeps the doc's
+        // current path. A string is sent only on a user-driven rename.
+        relativePath: RelativePath | undefined;
         contentBytes: Uint8Array;
     }): Promise<DocumentUpdateResponse> {
         const isText =
             !isBinary(contentBytes) &&
             isFileTypeMergable(
-                relativePath,
+                relativePath ?? record.remoteRelativePath,
                 (await this.serverConfig.getConfig()).mergeableFileExtensions
             );
 
diff --git a/frontend/sync-client/src/sync-operations/types.ts b/frontend/sync-client/src/sync-operations/types.ts
index 7a15aedd..80c74238 100644
--- a/frontend/sync-client/src/sync-operations/types.ts
+++ b/frontend/sync-client/src/sync-operations/types.ts
@@ -35,35 +35,36 @@ export enum SyncEventType {
 export type FileSyncEvent =
     | { type: SyncEventType.LocalCreate; path: RelativePath }
     | {
-          type: SyncEventType.LocalUpdate;
-          path: RelativePath;
-          oldPath?: RelativePath; // oldPath is undefined for content changes
-      }
+        type: SyncEventType.LocalUpdate;
+        path: RelativePath;
+        oldPath?: RelativePath; // oldPath is undefined for content changes
+    }
     | { type: SyncEventType.LocalDelete; path: RelativePath }
     | {
-          type: SyncEventType.RemoteChange;
-          remoteVersion: DocumentVersionWithoutContent;
-      };
+        type: SyncEventType.RemoteChange;
+        remoteVersion: DocumentVersionWithoutContent;
+    };
 
 export type SyncEvent =
     | {
-          type: SyncEventType.LocalCreate;
-          path: RelativePath; // current path on disk
-          originalPath: RelativePath; // original path on disk when the event was queued
-          resolvers: PromiseWithResolvers<DocumentId>;
-      }
+        type: SyncEventType.LocalCreate;
+        path: RelativePath; // current path on disk
+        originalPath: RelativePath; // original path on disk when the event was queued
+        resolvers: PromiseWithResolvers<DocumentId>;
+    }
     | {
-          type: SyncEventType.LocalUpdate;
-          documentId: DocumentId | Promise<DocumentId>; // if it's a promise, the promise is fulfilled once the document's create event is processed
-          path: RelativePath; // current path on disk
-          originalPath: RelativePath; // original path on disk when the event was queued
-          // no need to store the old path in case of a rename; the server will figure it out from the parent's path
-      }
+        type: SyncEventType.LocalUpdate;
+        documentId: DocumentId | Promise<DocumentId>; // if it's a promise, the promise is fulfilled once the document's create event is processed
+        path: RelativePath; // current path on disk
+        originalPath: RelativePath; // original path on disk when the event was queued
+        isUserRename: boolean; // true iff this event was queued because the user renamed the file
+    }
     | {
-          type: SyncEventType.LocalDelete;
-          documentId: DocumentId | Promise<DocumentId>; // if it's a promise, the promise is fulfilled once the document's create event is processed
-      }
+        type: SyncEventType.LocalDelete;
+        documentId: DocumentId | Promise<DocumentId>; // if it's a promise, the promise is fulfilled once the document's create event is processed
+        path: RelativePath;  // only used for showing on the UI
+    }
     | {
-          type: SyncEventType.RemoteChange;
-          remoteVersion: DocumentVersionWithoutContent;
-      };
+        type: SyncEventType.RemoteChange;
+        remoteVersion: DocumentVersionWithoutContent;
+    };