diff --git a/apps/desktop/src/components/workpanel/FilesTab.tsx b/apps/desktop/src/components/workpanel/FilesTab.tsx
index b73418a9e..5f5418231 100644
--- a/apps/desktop/src/components/workpanel/FilesTab.tsx
+++ b/apps/desktop/src/components/workpanel/FilesTab.tsx
@@ -126,7 +126,7 @@ function HighlightedText({ path, content }: { path: string; content: string }) {
     <pre className="file-viewer-code">
       {tokens
         ? tokens.tokens.map((row, i) => (
-            <div className="file-viewer-line" key={i}>
+            <div className="file-viewer-line" data-line={i + 1} key={i}>
               {row.length === 0
                 ? "\n"
                 : row.map((token, j) => (
@@ -137,7 +137,7 @@ function HighlightedText({ path, content }: { path: string; content: string }) {
             </div>
           ))
         : visible.split("\n").map((line, i) => (
-            <div className="file-viewer-line" key={i}>
+            <div className="file-viewer-line" data-line={i + 1} key={i}>
               {line || "\n"}
             </div>
           ))}
@@ -163,8 +163,10 @@ export function FilesTab() {
   const [expanded, setExpanded] = useState<Set<string>>(new Set());
   const [selected, setSelected] = useState<string | null>(null);
   const [selectedMimeType, setSelectedMimeType] = useState<string | undefined>();
+  const [selectedLine, setSelectedLine] = useState<number | undefined>();
   const [file, setFile] = useState<FsReadResult | null>(null);
   const [fileError, setFileError] = useState(false);
+  const viewerBodyRef = useRef<HTMLDivElement>(null);
 
   // Workspace switches reset all browsing state. Guarded so it only fires on
   // an actual root change: an unconditional [root] effect also runs on the
@@ -178,6 +180,7 @@ export function FilesTab() {
     setExpanded(new Set());
     setSelected(null);
     setSelectedMimeType(undefined);
+    setSelectedLine(undefined);
     setFile(null);
     setFileError(false);
   }, [root]);
@@ -215,17 +218,32 @@ export function FilesTab() {
     [dirs, loadDir],
   );
 
-  const openFile = useCallback(async (rel: string, mimeType?: string) => {
-    setSelected(rel);
-    setSelectedMimeType(mimeType);
-    setFile(null);
-    setFileError(false);
-    try {
-      setFile(await api.fsRead(rel, mimeType));
-    } catch {
-      setFileError(true);
-    }
-  }, []);
+  const openFile = useCallback(
+    async (rel: string, mimeType?: string, position?: { line?: number; column?: number }) => {
+      setSelected(rel);
+      setSelectedMimeType(mimeType);
+      setSelectedLine(position?.line);
+      setFile(null);
+      setFileError(false);
+      try {
+        setFile(await api.fsRead(rel, mimeType));
+      } catch {
+        setFileError(true);
+      }
+    },
+    [],
+  );
+
+  useEffect(() => {
+    if (!file || selectedLine == null) return;
+    const frame = requestAnimationFrame(() => {
+      const lineNode = viewerBodyRef.current?.querySelector(
+        `[data-line="${selectedLine}"]`,
+      );
+      lineNode?.scrollIntoView({ block: "center" });
+    });
+    return () => cancelAnimationFrame(frame);
+  }, [file, selectedLine]);
 
   const openMp4 = useCallback(async () => {
     if (!selected) return;
@@ -260,7 +278,10 @@ export function FilesTab() {
       setExpanded((prev) => new Set([...prev, ...ancestors]));
       for (const dir of ancestors) void loadDir(dir);
     }
-    void openFile(path, fileRequest.mimeType);
+    void openFile(path, fileRequest.mimeType, {
+      line: fileRequest.line,
+      column: fileRequest.column,
+    });
   }, [fileRequest, root, loadDir, openFile]);
 
   const renderDir = (rel: string, depth: number): React.ReactNode => {
@@ -337,6 +358,7 @@ export function FilesTab() {
             onClick={() => {
               setSelected(null);
               setSelectedMimeType(undefined);
+              setSelectedLine(undefined);
               setFile(null);
             }}
           >
@@ -356,12 +378,15 @@ export function FilesTab() {
             <IconExternal size={14} />
           </TooltipButton>
         </div>
-        <div className="file-viewer-body">
+        <div className="file-viewer-body" ref={viewerBodyRef}>
           {fileError ? (
             <WorkTabEmpty icon={IconFileText} title={t("panel.files.error")} />
           ) : !file ? (
             <div className="file-tree-note">{t("panel.files.loading")}</div>
-          ) : file.kind === "text" && isMarkdownPath(selected) ? (
+          ) :
+          file.kind === "text" &&
+          isMarkdownPath(selected) &&
+          selectedLine === undefined ? (
             <div className="file-viewer-markdown prose-chat">
               <Markdown source={file.content ?? ""} baseDir={fileDirOf(selected)} />
             </div>
diff --git a/apps/desktop/src/features/chat/transcript/shared.tsx b/apps/desktop/src/features/chat/transcript/shared.tsx
index 431bcf198..fa227cb8f 100644
--- a/apps/desktop/src/features/chat/transcript/shared.tsx
+++ b/apps/desktop/src/features/chat/transcript/shared.tsx
@@ -423,13 +423,22 @@ export function FileRefChip({
   kind,
   mimeType,
   onOpen,
+  line,
+  column,
   ...position
 }: {
   name: string;
   path: string;
   kind?: "image" | "file";
   mimeType?: string;
-  onOpen: (path: string, baseDir?: string, mimeType?: string) => void;
+  onOpen: (
+    path: string,
+    baseDir?: string,
+    mimeType?: string,
+    position?: { line?: number; column?: number },
+  ) => void;
+  line?: number;
+  column?: number;
 } & SourcePositionProps) {
   const { t } = useTranslation();
   const Icon = fileChipIcon(name, kind);
@@ -443,7 +452,7 @@ export function FileRefChip({
         {...position}
         title={`${html ? t("chat.previewUrl") : t("chat.openFile")} — ${path}`}
         aria-label={`${name} — ${path}`}
-        onClick={() => onOpen(path, undefined, mimeType)}
+        onClick={() => onOpen(path, undefined, mimeType, { line, column })}
         onContextMenu={(event) => openFileMenu(event, { path })}
       >
         <span className="composer-chip-icon" aria-hidden>
@@ -556,6 +565,8 @@ export function LinkifiedText({ text, attachments }: { text: string; attachments
             key={index}
             name={segment.label}
             path={segment.target.path}
+            line={segment.target.line}
+            column={segment.target.column}
             onOpen={openFileRef}
             {...position}
           />
diff --git a/apps/desktop/src/hooks/use-preview-target.ts b/apps/desktop/src/hooks/use-preview-target.ts
index 2cbac818b..633a2e62f 100644
--- a/apps/desktop/src/hooks/use-preview-target.ts
+++ b/apps/desktop/src/hooks/use-preview-target.ts
@@ -27,7 +27,12 @@ export function useOpenPreviewTarget() {
   const openFileRef = useOpenChatFileRef();
   return useCallback(
     (target: ChatPreviewTarget) =>
-      target.kind === "file" ? openFileRef(target.path) : openHttpUrl(target.url),
+      target.kind === "file"
+        ? openFileRef(target.path, undefined, undefined, {
+            line: target.line,
+            column: target.column,
+          })
+        : openHttpUrl(target.url),
     [openFileRef],
   );
 }
@@ -131,10 +136,13 @@ function useResolveChatFileRef() {
  * Open a file reference the conversation mentioned.
  *
  * A workspace `.html` page in the primary folder stays with the side browser
- * (ADR 0163): it is a page to run, not a file to read. A project file opens in
- * the bundled file view when that view is installed and on the host file tab
- * otherwise; scratch and attachment files live outside the project and always
- * take the host file tab.
+ * (ADR 0163): it is a page to run, not a file to read. A plain project file
+ * opens in the bundled file view when available; a positioned `path:line`
+ * reference uses the host file tab, which can scroll to the requested line.
+ * The plugin view accepts opaque path locations and has no line-navigation
+ * contract, so positioned references keep their path unchanged and use the
+ * host viewer's existing scroll support. Scratch and attachment files also use
+ * the host file tab.
  */
 export function useOpenChatFileRef() {
   const resolveRef = useResolveChatFileRef();
@@ -149,11 +157,20 @@ export function useOpenChatFileRef() {
   );
 
   return useCallback(
-    (path: string, baseDir?: string, mimeType?: string) => {
+    (
+      path: string,
+      baseDir?: string,
+      mimeType?: string,
+      position?: { line?: number; column?: number },
+    ) => {
+      const line = position?.line;
+      const column = position?.column;
       void (async () => {
         const resolved = await resolveRef(path, baseDir);
         if (!resolved) return;
+        const hasPosition = line !== undefined || column !== undefined;
         if (
+          !hasPosition &&
           resolved.inProject &&
           resolved.primary &&
           resolved.relativePath &&
@@ -162,11 +179,15 @@ export function useOpenChatFileRef() {
           openUrl(resolved.relativePath);
           return;
         }
-        if (resolved.inProject && fileViewAvailable) {
+        if (
+          resolved.inProject &&
+          fileViewAvailable &&
+          !hasPosition
+        ) {
           openTab(fileManagerPluginTab(resolved.path));
           return;
         }
-        openFile(resolved.path, mimeType);
+        openFile(resolved.path, mimeType, { line, column });
       })();
     },
     [fileViewAvailable, openFile, openTab, openUrl, resolveRef],
diff --git a/apps/desktop/src/lib/chat-links.ts b/apps/desktop/src/lib/chat-links.ts
index d2c412d87..02a39b9df 100644
--- a/apps/desktop/src/lib/chat-links.ts
+++ b/apps/desktop/src/lib/chat-links.ts
@@ -52,6 +52,21 @@ function stripLineRef(path: string): string {
   return path.replace(/:\d+(?::\d+)?$/, "");
 }
 
+/** Trailing `:line[:col]` on a file token, if any. */
+export function parseFileRefPosition(
+  text: string,
+): { line: number; column?: number } | null {
+  const token = text.trim().replace(/[.,!?;:，。！？；：]+$/u, "");
+  const match = token.match(/:(\d+)(?::(\d+))?$/);
+  if (!match) return null;
+  const line = Number(match[1]);
+  if (!Number.isFinite(line) || line < 1) return null;
+  const column = match[2] !== undefined ? Number(match[2]) : undefined;
+  return column !== undefined && Number.isFinite(column) && column >= 1
+    ? { line, column }
+    : { line };
+}
+
 function leafName(path: string): string {
   const normalized = path.replaceAll("\\", "/").replace(/\/+$/, "");
   return normalized.slice(normalized.lastIndexOf("/") + 1) || path;
@@ -188,7 +203,7 @@ export function toWorkspaceRel(
 }
 
 export type ChatPreviewTarget =
-  | { kind: "file"; path: string }
+  | { kind: "file"; path: string; line?: number; column?: number }
   | { kind: "url"; url: string };
 
 /** Resolve one raw chat token into a previewable target, or null. */
@@ -199,17 +214,24 @@ export function resolvePreviewTarget(
 ): ChatPreviewTarget | null {
   const trimmed = text.trim();
   if (isHttpUrl(trimmed)) return { kind: "url", url: trimmed };
-  const at = unwrapAtFileRef(trimmed);
+  const position = parseFileRefPosition(trimmed);
+  const pathText = position
+    ? trimmed.replace(/[.,!?;:，。！？；：]+$/u, "")
+    : trimmed;
+  const at = unwrapAtFileRef(pathText);
   if (at) {
-    if (isAbsoluteFilePath(at)) return { kind: "file", path: at };
-    const rel = toWorkspaceRel(at, root, baseDir);
-    return rel ? { kind: "file", path: rel } : null;
+    const cleaned = stripLineRef(at);
+    if (isAbsoluteFilePath(cleaned)) {
+      return { kind: "file", path: cleaned, ...(position ?? {}) };
+    }
+    const rel = toWorkspaceRel(cleaned, root, baseDir);
+    return rel ? { kind: "file", path: rel, ...(position ?? {}) } : null;
   }
-  const file = parseFileRef(trimmed);
+  const file = parseFileRef(pathText);
   if (!file) return null;
-  if (isAbsoluteFilePath(file)) return { kind: "file", path: file };
+  if (isAbsoluteFilePath(file)) return { kind: "file", path: file, ...(position ?? {}) };
   const rel = toWorkspaceRel(file, root, baseDir);
-  return rel ? { kind: "file", path: rel } : null;
+  return rel ? { kind: "file", path: rel, ...(position ?? {}) } : null;
 }
 
 /** Tool-call args → preview target (Read/Write/Edit paths, fetch URLs). */
diff --git a/apps/desktop/src/lib/work-panel-tabs.ts b/apps/desktop/src/lib/work-panel-tabs.ts
index 2e57d28de..dfa6b65b1 100644
--- a/apps/desktop/src/lib/work-panel-tabs.ts
+++ b/apps/desktop/src/lib/work-panel-tabs.ts
@@ -15,6 +15,9 @@ export type WorkPanelTab = {
   location?: string;
   /** Stored attachment mimeType for extension-less `attachments/<sha256>` images. */
   mimeType?: string;
+  /** Optional 1-based line/column for host file tabs (chat `path:line` refs). */
+  line?: number;
+  column?: number;
 };
 
 export type WorkPanelTabsState = {
@@ -24,9 +27,30 @@ export type WorkPanelTabsState = {
 
 export type WorkPanelContext = WorkPanelTabsState & {
   open: boolean;
-  fileRequest: { path: string; seq: number; mimeType?: string } | null;
+  fileRequest: {
+    path: string;
+    seq: number;
+    mimeType?: string;
+    line?: number;
+    column?: number;
+  } | null;
 };
 
+/** Build the file-view request represented by an active file tab. */
+export function createWorkPanelFileRequest(
+  tab: WorkPanelTab,
+  seq: number,
+): WorkPanelContext["fileRequest"] {
+  if (tab.kind !== "file" || !tab.resource) return null;
+  return {
+    path: tab.resource,
+    seq,
+    ...(tab.mimeType ? { mimeType: tab.mimeType } : {}),
+    ...(tab.line != null ? { line: tab.line } : {}),
+    ...(tab.column != null ? { column: tab.column } : {}),
+  };
+}
+
 let newWorkPanelTabSequence = 0;
 
 export function emptyWorkPanelContext(): WorkPanelContext {
@@ -267,13 +291,19 @@ export function normalizeWorkPanelFilePath(path: string): string {
   return absolute ? `/${normalized}` : normalized;
 }
 
-export function fileWorkPanelTab(path: string, mimeType?: string): WorkPanelTab {
+export function fileWorkPanelTab(
+  path: string,
+  mimeType?: string,
+  position?: { line?: number; column?: number },
+): WorkPanelTab {
   const resource = normalizeWorkPanelFilePath(path);
   return {
     id: `file:${resource}`,
     kind: "file",
     resource,
     ...(mimeType ? { mimeType } : {}),
+    ...(position?.line != null ? { line: position.line } : {}),
+    ...(position?.column != null ? { column: position.column } : {}),
   };
 }
 
diff --git a/apps/desktop/src/stores/app-state.ts b/apps/desktop/src/stores/app-state.ts
index a2103ea17..b509f07cb 100644
--- a/apps/desktop/src/stores/app-state.ts
+++ b/apps/desktop/src/stores/app-state.ts
@@ -368,7 +368,13 @@ export type AppState = {
   workPanelContexts: Record<string, WorkPanelContext>;
   workPanelWidth: number;
   /** Chat-initiated "preview this file" request consumed by the files viewer. */
-  workPanelFileRequest: { path: string; seq: number; mimeType?: string } | null;
+  workPanelFileRequest: {
+    path: string;
+    seq: number;
+    mimeType?: string;
+    line?: number;
+    column?: number;
+  } | null;
   /** Open (or activate) the transcript tab of one delegated subagent. */
   openSubagentTab: (delegationId: string, agentName?: string) => void;
   /** Abort one session's running turn, visible or not. */
@@ -392,7 +398,11 @@ export type AppState = {
   /** Hide the visible panel while retaining its session-owned context. */
   resetWorkPanelContext: () => void;
   setWorkPanelWidth: (width: number) => void;
-  openFileInWorkPanel: (path: string, mimeType?: string) => void;
+  openFileInWorkPanel: (
+    path: string,
+    mimeType?: string,
+    position?: { line?: number; column?: number },
+  ) => void;
   openUrlInWorkPanel: (url: string) => void;
   updateBrowserWorkPanelTab: (state: BrowserState) => void;
 };
diff --git a/apps/desktop/src/stores/slices/work-panel-slice.ts b/apps/desktop/src/stores/slices/work-panel-slice.ts
index 9f3afc9a5..2020c880c 100644
--- a/apps/desktop/src/stores/slices/work-panel-slice.ts
+++ b/apps/desktop/src/stores/slices/work-panel-slice.ts
@@ -4,6 +4,7 @@ import {
   browserPluginTab,
   browserTabLabel,
   closeWorkPanelTabState,
+  createWorkPanelFileRequest,
   emptyWorkPanelContext,
   fileWorkPanelTab,
   newWorkPanelTab,
@@ -14,6 +15,7 @@ import {
   subagentWorkPanelTab,
   switchWorkPanelContextState,
   type WorkPanelContext,
+  type WorkPanelTab,
 } from "../../lib/work-panel-tabs";
 import {
   WORK_PANEL_COMPACT_MIN_WIDTH,
@@ -116,6 +118,10 @@ export function createWorkPanelSlice({
   | "updateBrowserWorkPanelTab"
 > {
   let workPanelFileRequestSeq = 0;
+  const nextFileRequest = (tab?: WorkPanelTab): WorkPanelContext["fileRequest"] => {
+    if (!tab || tab.kind !== "file" || !tab.resource) return null;
+    return createWorkPanelFileRequest(tab, ++workPanelFileRequestSeq);
+  };
 
   return {
   openSubagentTab: (delegationId, agentName) => {
@@ -163,14 +169,7 @@ export function createWorkPanelSlice({
         },
         tab,
       );
-      const fileRequest =
-        tab.kind === "file" && tab.resource
-          ? {
-              path: tab.resource,
-              seq: ++workPanelFileRequestSeq,
-              ...(tab.mimeType ? { mimeType: tab.mimeType } : {}),
-            }
-          : context.fileRequest;
+      const fileRequest = nextFileRequest(tab) ?? context.fileRequest;
       const nextContext: WorkPanelContext = {
         open: true,
         tabs: next.tabs,
@@ -216,14 +215,7 @@ export function createWorkPanelSlice({
         tab,
       );
       const activeTab = next.tabs.find((item) => item.id === next.activeTabId);
-      const fileRequest =
-        activeTab?.kind === "file" && activeTab.resource
-          ? {
-              path: activeTab.resource,
-              seq: ++workPanelFileRequestSeq,
-              ...(activeTab.mimeType ? { mimeType: activeTab.mimeType } : {}),
-            }
-          : state.workPanelFileRequest;
+      const fileRequest = nextFileRequest(activeTab) ?? state.workPanelFileRequest;
       const nextContext: WorkPanelContext = {
         open: true,
         tabs: next.tabs,
@@ -254,14 +246,7 @@ export function createWorkPanelSlice({
         tabId,
       );
       const activeTab = next.tabs.find((tab) => tab.id === next.activeTabId);
-      const fileRequest =
-        activeTab?.kind === "file" && activeTab.resource
-          ? {
-              path: activeTab.resource,
-              seq: ++workPanelFileRequestSeq,
-              ...(activeTab.mimeType ? { mimeType: activeTab.mimeType } : {}),
-            }
-          : state.workPanelFileRequest;
+      const fileRequest = nextFileRequest(activeTab) ?? state.workPanelFileRequest;
       const nextContext: WorkPanelContext = {
         open: state.workPanelOpen,
         tabs: next.tabs,
@@ -325,14 +310,7 @@ export function createWorkPanelSlice({
         tabId,
       );
       const activeTab = next.tabs.find((tab) => tab.id === next.activeTabId);
-      const fileRequest =
-        activeTab?.kind === "file" && activeTab.resource
-          ? {
-              path: activeTab.resource,
-              seq: ++workPanelFileRequestSeq,
-              ...(activeTab.mimeType ? { mimeType: activeTab.mimeType } : {}),
-            }
-          : state.workPanelFileRequest;
+      const fileRequest = nextFileRequest(activeTab) ?? state.workPanelFileRequest;
       const nextContext: WorkPanelContext = {
         // Closing the final tab leaves the panel open so the user can choose
         // another tool from the new-tab launcher instead of losing the dock.
@@ -379,8 +357,8 @@ export function createWorkPanelSlice({
     saveWorkPanelWidth(get().workPanelWidth);
   },
 
-  openFileInWorkPanel: (path, mimeType) => {
-    get().openWorkPanelTab(fileWorkPanelTab(path, mimeType));
+  openFileInWorkPanel: (path, mimeType, position) => {
+    get().openWorkPanelTab(fileWorkPanelTab(path, mimeType, position));
   },
   updateBrowserWorkPanelTab: (event) => {
     const sessionId = event.sessionId;
diff --git a/apps/desktop/test/chat-links.test.mjs b/apps/desktop/test/chat-links.test.mjs
index b9de2110c..ad23dd4df 100644
--- a/apps/desktop/test/chat-links.test.mjs
+++ b/apps/desktop/test/chat-links.test.mjs
@@ -9,6 +9,7 @@ import {
   isHttpUrl,
   linkifyMdastTree,
   parseFileRef,
+  parseFileRefPosition,
   remarkChatFileLinks,
   resolvePreviewTarget,
   splitChatText,
@@ -107,6 +108,7 @@ test("resolvePreviewTarget classifies urls and workspace files", () => {
   assert.deepEqual(resolvePreviewTarget("src/a.ts:10", ROOT), {
     kind: "file",
     path: "src/a.ts",
+    line: 10,
   });
   assert.deepEqual(resolvePreviewTarget("./README.md", ROOT, "docs"), {
     kind: "file",
@@ -729,3 +731,38 @@ test("adjacent parenthesis-wrapped URLs all remain independently linkable", () =
   assert.equal(segments.filter(s => s.kind === "target").length, 1000);
   assert.equal(segments.map(s => s.text).join(""), source);
 });
+
+test("parseFileRefPosition keeps :line[:col] that parseFileRef strips", () => {
+  assert.deepEqual(parseFileRefPosition("src/main.rs:42"), { line: 42 });
+  assert.deepEqual(parseFileRefPosition("src/main.rs:42:7"), { line: 42, column: 7 });
+  assert.deepEqual(parseFileRefPosition("src/main.rs:42."), { line: 42 });
+  assert.deepEqual(parseFileRefPosition("src/main.rs:42:7,"), { line: 42, column: 7 });
+  assert.equal(parseFileRefPosition("src/main.rs"), null);
+  assert.equal(parseFileRefPosition("src/main.rs:0"), null);
+});
+
+test("resolvePreviewTarget carries line/col on file chips (#681)", () => {
+  assert.deepEqual(resolvePreviewTarget("src/a.ts:42", ROOT), {
+    kind: "file",
+    path: "src/a.ts",
+    line: 42,
+  });
+  assert.deepEqual(resolvePreviewTarget("src/a.ts:42:7", ROOT), {
+    kind: "file",
+    path: "src/a.ts",
+    line: 42,
+    column: 7,
+  });
+  assert.deepEqual(resolvePreviewTarget("src/a.ts:42:7.", ROOT), {
+    kind: "file",
+    path: "src/a.ts",
+    line: 42,
+    column: 7,
+  });
+  assert.deepEqual(resolvePreviewTarget(`${ROOT}/src/a.ts:42:7`, ROOT), {
+    kind: "file",
+    path: `${ROOT}/src/a.ts`,
+    line: 42,
+    column: 7,
+  });
+});
diff --git a/apps/desktop/test/open-http-url.test.mjs b/apps/desktop/test/open-http-url.test.mjs
index 5afb76ce1..92f5475f3 100644
--- a/apps/desktop/test/open-http-url.test.mjs
+++ b/apps/desktop/test/open-http-url.test.mjs
@@ -164,7 +164,7 @@ test("previewable transcript URLs follow the link-open setting", () => {
   assert.match(previewSource, /import \{ openHttpUrl \} from "\.\.\/lib\/open-http-url"/);
   assert.match(
     previewSource,
-    /target\.kind === "file" \? openFileRef\(target\.path\) : openHttpUrl\(target\.url\)/,
+    /target\.kind === "file"\s*\?\s*openFileRef\(target\.path,[\s\S]*?\)\s*:\s*openHttpUrl\(target\.url\)/,
   );
 });
 
diff --git a/apps/desktop/test/transcript-file-chips.test.mjs b/apps/desktop/test/transcript-file-chips.test.mjs
index cd37a0945..ae133e087 100644
--- a/apps/desktop/test/transcript-file-chips.test.mjs
+++ b/apps/desktop/test/transcript-file-chips.test.mjs
@@ -8,13 +8,14 @@ import test from "node:test";
 
 const read = (path) => readFile(new URL(path, import.meta.url), "utf8");
 
-const [transcript, styles, hook, api, toolDetails, toolRow] = await Promise.all([
+const [transcript, styles, hook, api, toolDetails, toolRow, filesTab] = await Promise.all([
   readTranscriptSource(),
   read("../src/styles/chat-links.css"),
   read("../src/hooks/use-preview-target.ts"),
   read("../src/lib/api.ts"),
   read("../src/components/ToolDetails.tsx"),
   readTranscriptModule("ToolRow.tsx"),
+  read("../src/components/workpanel/FilesTab.tsx"),
 ]);
 
 test("sent user-message file refs render as composer-like chips", () => {
@@ -25,7 +26,7 @@ test("sent user-message file refs render as composer-like chips", () => {
   assert.match(transcript, /composer-chip-name/);
   assert.match(styles, /\.chat-file-chip[\s\S]*?appearance: none/);
   assert.match(transcript, /mimeType=\{attachment\.mimeType\}/);
-  assert.match(transcript, /onOpen\(path, undefined, mimeType\)/);
+  assert.match(transcript, /onOpen\(path, undefined, mimeType, \{ line, column \}\)/);
 });
 
 test("a file chip is routed by where the reference resolved, never optimistically", () => {
@@ -44,14 +45,23 @@ test("a file chip is routed by where the reference resolved, never optimisticall
   assert.match(hook, /resolved\.primary &&/);
   assert.match(hook, /isHtmlFilePath\(resolved\.relativePath\)/);
   assert.match(hook, /openUrl\(resolved\.relativePath\)/);
-  // A project file prefers the bundled file view; without that plugin the
-  // host file tab is the same surface this hook used before.
+  // Plain project files prefer the bundled file view. A path:line reference
+  // uses the host file tab because the bundled view has no line-navigation API.
   assert.match(hook, /FILE_MANAGER_PLUGIN_TAB/);
+  assert.match(hook, /const hasPosition = line !== undefined \|\| column !== undefined/);
+  assert.match(hook, /!hasPosition[\s\S]*?isHtmlFilePath/);
+  assert.match(hook, /!hasPosition[\s\S]*?fileViewAvailable/);
   assert.match(hook, /fileManagerPluginTab\(resolved\.path\)/);
+  assert.match(filesTab, /data-line=\{i \+ 1\}/);
+  assert.match(filesTab, /viewerBodyRef\.current\?\.querySelector/);
+  assert.match(filesTab, /if \(!file \|\| selectedLine == null\) return/);
+  assert.match(filesTab, /data-line="\$\{selectedLine\}"/);
+  assert.match(filesTab, /return \(\) => cancelAnimationFrame\(frame\)/);
+  assert.match(filesTab, /selectedLine === undefined/);
   // Session scratch and attachment files live outside the plugin's project
-  // roots, so completion hands them back as an absolute path.
+  // roots, and positioned references need the host viewer's line navigation.
   assert.match(hook, /inProject: false/);
-  assert.match(hook, /openFile\(resolved\.path, mimeType\)/);
+  assert.match(hook, /openFile\(resolved\.path, mimeType, \{ line, column \}\)/);
   // The OS handoff is no longer what a chat click does; the channel itself
   // stays part of the public IPC surface.
   assert.doesNotMatch(hook, /api\.fsOpen\(/);
@@ -65,10 +75,8 @@ test("a tool row and a tool result row open a file where the message body does",
   // row land in the bundled file view too (ADR 0262). The call this replaces is
   // the one that let those surfaces pick the destination themselves.
   assert.match(hook, /const openFileRef = useOpenChatFileRef\(\);/);
-  assert.match(
-    hook,
-    /target\.kind === "file" \? openFileRef\(target\.path\) : openHttpUrl\(target\.url\)/,
-  );
+  assert.match(hook, /target\.kind === "file"[\s\S]*?openFileRef\(target\.path, undefined, undefined, \{/);
+  assert.match(hook, /line: target\.line,[\s\S]*?column: target\.column/);
   assert.doesNotMatch(hook, /openFile\(target\.path\)/);
   // Both surfaces still call that opener, and neither reaches the host viewer's
   // store action directly: the tool row summary carries the call's own path,
diff --git a/apps/desktop/test/work-panel-tabs.test.mjs b/apps/desktop/test/work-panel-tabs.test.mjs
index 98e1015e9..96fe3a9f9 100644
--- a/apps/desktop/test/work-panel-tabs.test.mjs
+++ b/apps/desktop/test/work-panel-tabs.test.mjs
@@ -6,6 +6,7 @@ const {
   activateWorkPanelTabState,
   browserPluginTab,
   closeWorkPanelTabState,
+  createWorkPanelFileRequest,
   emptyWorkPanelContext,
   fileWorkPanelTab,
   hasPluginView,
@@ -84,6 +85,22 @@ test("file tabs normalize lexical paths and remain distinct by resource", () =>
   assert.equal(normalizeWorkPanelFilePath("/repo/./src/../App.tsx"), "/repo/App.tsx");
 });
 
+test("file-view requests preserve a positioned file tab", () => {
+  const tab = fileWorkPanelTab("src/App.tsx", "text/typescript", {
+    line: 65,
+    column: 4,
+  });
+
+  assert.deepEqual(createWorkPanelFileRequest(tab, 7), {
+    path: "src/App.tsx",
+    seq: 7,
+    mimeType: "text/typescript",
+    line: 65,
+    column: 4,
+  });
+  assert.equal(createWorkPanelFileRequest(toolWorkPanelTab("review"), 8), null);
+});
+
 test("closing the active tab selects its right neighbor then its left", () => {
   const state = {
     tabs: [
diff --git a/apps/desktop/test/work-panel.test.mjs b/apps/desktop/test/work-panel.test.mjs
index 12d599bf8..432a146be 100644
--- a/apps/desktop/test/work-panel.test.mjs
+++ b/apps/desktop/test/work-panel.test.mjs
@@ -526,9 +526,13 @@ test("work panel context is retained by session instead of cleared on selection"
 
 test("file preview request ids stay unique across session contexts", () => {
   assert.match(storeSource, /let workPanelFileRequestSeq = 0/);
+  assert.match(
+    storeSource,
+    /const nextFileRequest = \(tab\?: WorkPanelTab\)[\s\S]*?createWorkPanelFileRequest\(tab, \+\+workPanelFileRequestSeq\)/,
+  );
   assert.ok(
-    storeSource.match(/seq:\s*\+\+workPanelFileRequestSeq/g)?.length >= 3,
-    "open and activation paths must use the shared request sequence",
+    storeSource.match(/nextFileRequest\((?:tab|activeTab)\)/g)?.length === 4,
+    "open, replace, activation, and close paths must share the position-preserving request",
   );
   assert.doesNotMatch(storeSource, /seq:\s*\([^)]*fileRequest\?\.seq[^)]*\) \+ 1/);
 });
diff --git a/docs/adr/0262-chat-file-refs-open-in-the-file-view.md b/docs/adr/0262-chat-file-refs-open-in-the-file-view.md
index 98ef6b0f3..840af419a 100644
--- a/docs/adr/0262-chat-file-refs-open-in-the-file-view.md
+++ b/docs/adr/0262-chat-file-refs-open-in-the-file-view.md
@@ -48,13 +48,17 @@ work-panel tab already carries was honoured by main for `pi.browser` only.
    - a reference that matches nothing opens **nothing** and reports itself. No
      empty panel, no blank browser page.
 2. **The destination follows where the reference resolved.** A project file
-   opens in the `pi.file-manager` view. A file in the session scratch or
-   attachment store opens in the host `file:` tab, because it lives outside that
-   view's project root — see point 4. A workspace `.html` / `.htm` file still
-   opens in the side browser (ADR 0163), for an agent reply and a user chip
-   alike: it is a page to run, not a file to read. When the file view is not
-   loaded, a project file falls back to the host `file:` tab, so the click never
-   regresses to nothing.
+   opens in the `pi.file-manager` view, except a `path:line` reference, which
+   opens in the host's read-only `file:` tab so the requested source line can
+   be brought into view. The bundled view accepts opaque path locations and has
+   no line-navigation contract; this keeps the path unchanged and uses the
+   host viewer's existing scroll support. A file in the session scratch or
+   attachment store opens in the
+   host `file:` tab, because it lives outside that view's project root — see
+   point 4. A workspace `.html` / `.htm` file still opens in the side browser
+   (ADR 0163), for an agent reply and a user chip alike: it is a page to run,
+   not a file to read. When the file view is not loaded, a project file falls
+   back to the host `file:` tab, so the click never regresses to nothing.
 3. **A contributed view's `location` stops being browser-only.** It travels as
    the view entry URL's `piViewOpen` query parameter on creation — the only
    channel that cannot race a document that has not run yet — and as the
diff --git a/docs/spec/04-ux/08-component-spec.md b/docs/spec/04-ux/08-component-spec.md
index 903dc5cdd..07c2baf10 100644
--- a/docs/spec/04-ux/08-component-spec.md
+++ b/docs/spec/04-ux/08-component-spec.md
@@ -1537,6 +1537,10 @@ storage but compose into one assistant turn until the next user message.
   content's left rule is itself a pointer and keyboard-focusable collapse
   control.
 - Hover code block: copy button appears
+- Click a transcript file reference with `:line[:column]`: resolve the file
+  first, then open it in the host `file:` tab and scroll the requested line into
+  view. Plain project-file references still prefer the bundled file view, whose
+  open contract does not carry a line position.
 - Hover or focus a minimap marker: show the localized sender and a bounded
   plaintext preview; multiple assistant fragments produced within one user
   turn are combined into one AI-response marker and preview; nearby markers
@@ -3414,6 +3418,8 @@ Anatomy:
   in the bundled `pi.file-manager` view (the host `file:` tab when that view is
   unavailable), a session-scratch or attachment file in the host `file:` tab,
   and a `.html`/`.htm` page of the primary folder in the side browser. A
+  positioned `path:line` reference uses the host read-only `file:` tab and
+  scrolls the requested line into view. A
   primary-folder file is addressed to the view as a project-relative path and a
   sibling-folder file as an absolute one, which is also how scratch and
   attachment files are addressed. A reference that matches no file opens nothing
diff --git a/docs/spec/06-delivery/04-e2e-test-plan.md b/docs/spec/06-delivery/04-e2e-test-plan.md
index c0efd920a..de013f2b5 100644
--- a/docs/spec/06-delivery/04-e2e-test-plan.md
+++ b/docs/spec/06-delivery/04-e2e-test-plan.md
@@ -8789,16 +8789,20 @@ must keep splitting are covered by `markdown-blocks.test.mjs`.
   6. Click a project file path in the conversation. Confirm it opens in this
      view on that file — a chat click now prefers the file view over the host
      `file:` tab.
-  7. Disable the File Manager plugin. Confirm the view disappears from the menu
+  7. Click a conversation reference to `src/example.ts:42`. Confirm the host
+     `file:` tab opens at line 42 even though the File Manager plugin is enabled.
+  8. Disable the File Manager plugin. Confirm the view disappears from the menu
      and the panel, and that a clicked conversation file path falls back to the
      host `file:<path>` tab under Open resources.
-  8. Re-enable it, then restart the app. Confirm the enabled state and the tree
+  9. Re-enable it, then restart the app. Confirm the enabled state and the tree
      return, and that the registry did not gain a duplicate row.
 - **Expected**: A panel surface runs entirely on the public plugin contribution
   channel, is user-disableable, cannot be uninstalled, and survives restart. Its
   host-mediated actions obey the declared `fs.read` scope, and its own reads and
   writes stay inside the jail of the one project folder it is browsing
-  (ADR 0241, ADR 0263).
+  (ADR 0241, ADR 0263). Plain project-file links open in the bundled view; a
+  positioned `path:line` reference opens the host file tab and scrolls the
+  requested line even while the plugin view is available.
 - **Specs linked**: `07-plugins/03-plugin-api.md` §3,
   `07-plugins/13-plugin-permissions-matrix.md` §2,
   `04-ux/08-component-spec.md` §5, ADR 0104, ADR 0109, ADR 0111,
@@ -16383,6 +16387,24 @@ renderer's durable transcript reads. No real model or provider is contacted.
   separate release qualification. No MCP, Codemode or virtual-router migration
   is included. See `docs/project/pi-0991-adoption.md` for candidate evidence.
 
+#### E2E-262: Transcript path:line opens and scrolls the host file viewer
+
+- **Preconditions:** Isolated Electron/Chromium, an active workspace and session,
+  the bundled file-manager view available, and deterministic filesystem IPC
+  fixtures.
+- **Steps:** Render a real transcript `path:line:column` reference followed by
+  sentence punctuation; click its verified file chip and wait for the host file
+  viewer to load.
+- **Expected:** Despite the bundled file-manager view being available, the
+  positioned reference opens in the host's read-only file tab. The file request
+  retains its line and column, and the viewer scrolls the requested line into
+  the visible center area. The path and file contents remain the same as the
+  reference target.
+- **Specs:** `04-ux/08` §11.8; ADR 0262.
+- **Status:** `node scripts/e2e-file-ref-line-scroll.mjs` mounts production
+  `LinkifiedText` and `FilesTab` in isolated Electron with filesystem IPC
+  fixtures; no real project files or provider are used.
+
 ### Imported-extension GUI executable discovery regression (#1173)
 
 Start dependency installation with a GUI-like PATH that cannot resolve Node/npm
diff --git a/docs/zh-CN/spec/04-ux/08-component-spec.md b/docs/zh-CN/spec/04-ux/08-component-spec.md
index cc9b60205..035ed757c 100644
--- a/docs/zh-CN/spec/04-ux/08-component-spec.md
+++ b/docs/zh-CN/spec/04-ux/08-component-spec.md
@@ -2340,6 +2340,8 @@ Live Voice 受现有开发者模式和开发构建门控约束，包含四种展
 - 发送的模板调用在记录中呈现为等宽命令
   来自消息的 `command` 字段的芯片而不是扩展的正文。
 - 已发送的 `@path` 文件引用（带引号或不带引号）画成与草稿相同的叶子名芯片。点击芯片先经 `pi-desktop/fs/resolveRef` 补全引用——搜索整个打开的项目，按项目组文件夹顺序、主文件夹优先（ADR 0263）——再按解析结果打开：项目文件在随应用打包的 `pi.file-manager` 视图中打开（该视图不可用时退回宿主 `file:` 选项卡），会话临时目录或附件文件在宿主 `file:` 选项卡中打开，主文件夹中的 `.html`/`.htm` 在侧边浏览器打开。交给该视图的地址跟随应答的文件夹：主文件夹中的文件用项目内相对路径传递，同一项目的同级文件夹中的文件用绝对路径传递，与会话临时目录和附件文件一致。什么都没匹配到时既不打开任何东西，也会自己报告出来，右键该芯片也一样；引用菜单除了在系统文件管理器中显示该文件，还提供复制完整地址与复制相对地址，发送的 `@path` 芯片、消息 Markdown 中的行内代码、本地链接与本地图片、工具行自己的文件路径、工具结果的文件列表或匹配列表中的路径、图片附件缩略图都提供同样的几项，并同样经这次补全与这套寻址规则；项目外的文件没有相对地址，会直接说明。系统默认应用不再由这次点击触发。HTTP(S) URL 仍是侧边浏览器的文本链接。
+带行号的 `path:line` 引用使用宿主只读 `file:` 选项卡，并将目标行滚动到可见区域。
+
 - 状态：键盘活动行使用共享 `kb-active` 处理；空的
   查询列出所有内容（斜杠）/最近索引的顺序（文件）；零
 匹配呈现本地化的空行并且菜单计为关闭
diff --git a/docs/zh-CN/spec/06-delivery/04-e2e-test-plan.md b/docs/zh-CN/spec/06-delivery/04-e2e-test-plan.md
index d2f08da03..abaecc5f1 100644
--- a/docs/zh-CN/spec/06-delivery/04-e2e-test-plan.md
+++ b/docs/zh-CN/spec/06-delivery/04-e2e-test-plan.md
@@ -9270,6 +9270,14 @@ the latest destination. These assertions measure work counts, not device FPS.
 - **里程碑：** M6+
 - **状态：** 单测和源码契约覆盖（`update-cache.test.mjs`、`auto-update.test.mjs`）；仍需 Windows 安装器/E2E 验证。
 
+#### E2E-262：聊天 path:line 引用打开文件并滚动到目标行
+
+- **前提：** 隔离 Electron/Chromium、活动工作区和会话、可用的随应用打包文件管理器视图，以及确定性的文件系统 IPC fixture。
+- **步骤：** 渲染真实聊天中的 `path:line:column` 引用并在末尾加句末标点；点击已验证的文件芯片，等待宿主文件查看器加载。
+- **预期：** 即使文件管理器视图可用，带位置的引用仍打开宿主只读文件选项卡。文件请求保留行列号，查看器滚动到视口中间的目标行；打开路径和文件内容与引用目标一致。
+- **规格：** `04-ux/08` §11.8；ADR 0262。
+- **状态：** `node scripts/e2e-file-ref-line-scroll.mjs` 在隔离 Electron 中挂载生产 `LinkifiedText` 与 `FilesTab`，并通过文件系统 IPC fixture 提供文件内容；不访问真实项目文件或模型服务。
+
 ### 导入扩展时发现 GUI 环境下的可执行文件回归（#1173）
 
 使用无法解析 Node/npm 的 GUI 风格 `PATH` 启动依赖安装，并在 `~/.local/bin` 准备可信 fixture 安装。
diff --git a/scripts/e2e-file-ref-line-scroll.mjs b/scripts/e2e-file-ref-line-scroll.mjs
new file mode 100644
index 000000000..c0603c7df
--- /dev/null
+++ b/scripts/e2e-file-ref-line-scroll.mjs
@@ -0,0 +1,97 @@
+#!/usr/bin/env node
+/** Follow a real transcript path:line chip into the production host file viewer. */
+import assert from "node:assert/strict";
+import { spawn } from "node:child_process";
+import { createRequire } from "node:module";
+import { mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { repositoryRoot, resolveElectronBinary } from "./e2e/boot.mjs";
+
+const root = repositoryRoot();
+const require = createRequire(join(root, "packages/agent-runtime/package.json"));
+const { build } = require("esbuild");
+const temp = await mkdtemp(join(tmpdir(), "pi-file-ref-line-scroll-"));
+try {
+  await build({
+    entryPoints: [join(root, "scripts/e2e/file-ref-line-scroll.tsx")],
+    outfile: join(temp, "renderer.js"),
+    bundle: true,
+    platform: "browser",
+    format: "iife",
+    jsx: "automatic",
+    define: { "process.env.NODE_ENV": '"production"', "import.meta.env.DEV": "false" },
+    loader: { ".css": "empty" },
+    alias: {
+      "@pi-desktop/i18n": join(root, "packages/i18n/src/index.ts"),
+      react: join(root, "apps/desktop/node_modules/react"),
+      "react-dom": join(root, "apps/desktop/node_modules/react-dom"),
+    },
+    nodePaths: [join(root, "apps/desktop/node_modules")],
+  });
+  const viewerStyles = await readFile(join(root, "apps/desktop/src/styles/work-panel.css"), "utf8");
+  await writeFile(join(temp, "work-panel.css"), `${viewerStyles}\nhtml,body,#root{height:100%;margin:0}#root{display:flex;flex-direction:column}.fixture-chat{flex:0 0 auto;padding:8px}`);
+  await writeFile(
+    join(temp, "index.html"),
+    '<!doctype html><meta charset="utf-8"><link rel="stylesheet" href="work-panel.css"><div id="root"></div><script src="renderer.js"></script>',
+  );
+  await writeFile(
+    join(temp, "main.cjs"),
+    `
+const { app, BrowserWindow } = require("electron");
+const path = require("node:path");
+app.disableHardwareAcceleration();
+app.setPath("userData", path.join(__dirname, "profile"));
+app.whenReady().then(async () => {
+  const window = new BrowserWindow({ show: false, width: 900, height: 420,
+    webPreferences: { sandbox: true, contextIsolation: true, nodeIntegration: false, backgroundThrottling: false } });
+  window.webContents.on("console-message", (event) => console.error(event.message));
+  try {
+    await window.loadFile(path.join(__dirname, "index.html"));
+    const result = await window.webContents.executeJavaScript("window.fileRefLineScrollProbe()");
+    console.log("FILE_REF_LINE_SCROLL " + JSON.stringify(result));
+    app.exit(0);
+  } catch (error) {
+    console.error("FILE_REF_LINE_SCROLL " + (error?.stack ?? String(error)));
+    app.exit(1);
+  }
+});
+`,
+  );
+  const env = { ...process.env };
+  delete env.ELECTRON_RUN_AS_NODE;
+  const child = spawn(resolveElectronBinary(root).electronBinary, [
+    "--headless=new",
+    "--disable-gpu",
+    join(temp, "main.cjs"),
+  ], { env, stdio: ["ignore", "pipe", "pipe"] });
+  let output = "";
+  for (const stream of [child.stdout, child.stderr]) {
+    stream.on("data", (chunk) => { output += chunk; });
+  }
+  const timeout = setTimeout(() => child.kill("SIGKILL"), 45_000);
+  let code;
+  try {
+    code = await new Promise((resolve, reject) => {
+      child.once("error", reject);
+      child.once("close", resolve);
+    });
+  } finally {
+    clearTimeout(timeout);
+  }
+  const line = output.split(/\r?\n/).find((item) => item.startsWith("FILE_REF_LINE_SCROLL {"));
+  assert(line, `renderer returned no file reference result (exit=${code}): ${output.slice(-4000)}`);
+  const result = JSON.parse(line.slice("FILE_REF_LINE_SCROLL ".length));
+  console.log(line);
+  assert.equal(code, 0, output.slice(-4000));
+  assert.equal(result.fileManagerAvailable, true, "fixture must use the normal project-file setup");
+  assert.deepEqual(result.resolveRefs, ["src/scroll-target.txt", "src/scroll-target.txt"]);
+  assert.deepEqual(result.readPaths, ["src/scroll-target.txt"]);
+  assert.equal(result.selectedPath, "src/scroll-target.txt");
+  assert.deepEqual(result.request, { path: "src/scroll-target.txt", seq: 1, line: 65, column: 4 });
+  assert.deepEqual(result.scrollCall, { line: "65", block: "center" });
+  assert.ok(result.scrollTop > 0, "host file viewer did not scroll away from the top");
+  assert.equal(result.targetLineVisible, true, "requested line is outside the visible viewer area");
+} finally {
+  await rm(temp, { recursive: true, force: true });
+}
diff --git a/scripts/e2e/file-ref-line-scroll.tsx b/scripts/e2e/file-ref-line-scroll.tsx
new file mode 100644
index 000000000..4ae88a117
--- /dev/null
+++ b/scripts/e2e/file-ref-line-scroll.tsx
@@ -0,0 +1,162 @@
+import { createRoot } from "react-dom/client";
+import { flushSync } from "react-dom";
+import { createInstance } from "i18next";
+import { I18nextProvider, initReactI18next } from "react-i18next";
+import { IPC } from "@pi-desktop/shared";
+import { catalogs, flattenCatalog } from "@pi-desktop/i18n";
+import { FilesTab } from "../../apps/desktop/src/components/workpanel/FilesTab";
+import { LinkifiedText } from "../../apps/desktop/src/features/chat/transcript/shared";
+import { useAppStore } from "../../apps/desktop/src/stores/app-store";
+import { splitChatText } from "../../apps/desktop/src/lib/chat-links";
+
+const targetPath = "src/scroll-target.txt";
+const targetLine = 65;
+const content = Array.from({ length: 90 }, (_, index) => `line ${index + 1}`).join("\n");
+const resolveRefs: string[] = [];
+const readPaths: string[] = [];
+const scrollCalls: Array<{ line: string | undefined; block?: string }> = [];
+
+window.piDesktop = {
+  platform: "darwin",
+  channels: IPC,
+  on: () => () => {},
+  async invoke(channel, ...args) {
+    const input = args[0] as Record<string, unknown> | undefined;
+    if (channel === IPC.invoke.fsResolveRef) {
+      const ref = String(input?.ref ?? "");
+      resolveRefs.push(ref);
+      return {
+        ok: true,
+        data: {
+          match: {
+            root: "workspace",
+            relativePath: targetPath,
+            absolutePath: `/workspace/${targetPath}`,
+            matchedBy: "exact-relative",
+            projectRoot: { path: "/workspace", name: "Fixture", primary: true },
+          },
+        },
+      };
+    }
+    if (channel === IPC.invoke.fsList) {
+      return { ok: true, data: { entries: [] } };
+    }
+    if (channel === IPC.invoke.fsRead) {
+      const path = String(input?.path ?? "");
+      readPaths.push(path);
+      return { ok: true, data: { kind: "text", content, size: content.length } };
+    }
+    throw new Error(`Unexpected file viewer IPC: ${channel}`);
+  },
+};
+
+useAppStore.setState({
+  workspace: { path: "/workspace", name: "Fixture" },
+  activeSessionId: "fixture-session",
+  pluginViews: [{ pluginId: "pi.file-manager", viewId: "manager" }],
+  workPanelOpen: false,
+  workPanelTabs: [],
+  activeWorkPanelTabId: null,
+  workPanelFileRequest: null,
+});
+
+const nativeScrollIntoView = HTMLElement.prototype.scrollIntoView;
+if (!nativeScrollIntoView) throw new Error("Chromium scrollIntoView is unavailable");
+HTMLElement.prototype.scrollIntoView = function (options?: ScrollIntoViewOptions) {
+  scrollCalls.push({
+    line: this.getAttribute("data-line") ?? undefined,
+    block: options?.block,
+  });
+  nativeScrollIntoView.call(this, options);
+};
+
+const i18n = createInstance();
+void i18n
+  .use(initReactI18next)
+  .init({
+    lng: "en",
+    fallbackLng: "en",
+    keySeparator: false,
+    resources: { en: { translation: flattenCatalog(catalogs.en) } },
+    interpolation: { escapeValue: false },
+  })
+  .then(() => {
+    const root = createRoot(document.getElementById("root")!);
+    flushSync(() =>
+      root.render(
+        <I18nextProvider i18n={i18n}>
+          <div className="fixture-chat">
+            <LinkifiedText text={`Review ${targetPath}:${targetLine}:4.`} />
+          </div>
+          <FilesTab />
+        </I18nextProvider>,
+      ),
+    );
+
+    window.fileRefLineScrollProbe = async () => {
+      const until = async (predicate: () => boolean, label: string) => {
+        for (let frame = 0; frame < 180; frame++) {
+          if (predicate()) return true;
+          await new Promise<void>((resolve) => requestAnimationFrame(() => resolve()));
+        }
+        return false;
+      };
+
+      if (!(await until(
+        () => Boolean(document.querySelector<HTMLButtonElement>(".chat-file-chip")),
+        "verified transcript chip",
+      ))) throw new Error("The verified file reference chip did not render");
+      document.querySelector<HTMLButtonElement>(".chat-file-chip")!.click();
+      if (!(await until(
+        () => Boolean(document.querySelector(".file-viewer-path")) && readPaths.length > 0,
+        "host viewer file load",
+      ))) throw new Error(`Host file viewer did not load: ${JSON.stringify({ resolveRefs, readPaths, request: useAppStore.getState().workPanelFileRequest })}`);
+      await until(() => scrollCalls.length > 0, "host viewer line scroll");
+
+      const viewer = document.querySelector<HTMLElement>(".file-viewer-body");
+      const line = viewer?.querySelector<HTMLElement>(`[data-line="${targetLine}"]`);
+      if (!viewer || !line) throw new Error("The requested source line was not rendered");
+      const viewerRect = viewer.getBoundingClientRect();
+      const lineRect = line.getBoundingClientRect();
+      const request = useAppStore.getState().workPanelFileRequest;
+      return {
+        fileManagerAvailable: useAppStore.getState().pluginViews.some(
+          (view) => view.pluginId === "pi.file-manager" && view.viewId === "manager",
+        ),
+        selectedPath: document.querySelector(".file-viewer-path")?.textContent,
+        segments: splitChatText(`Review ${targetPath}:${targetLine}:4.`, "/workspace"),
+        resolveRefs,
+        readPaths,
+        request,
+        scrollCall: scrollCalls.at(-1) ?? null,
+        scrollTop: viewer.scrollTop,
+        targetLineVisible: lineRect.top >= viewerRect.top && lineRect.bottom <= viewerRect.bottom,
+      };
+    };
+  })
+  .catch((error: unknown) => {
+    console.error(error);
+    throw error;
+  });
+
+declare global {
+  interface Window {
+    piDesktop?: {
+      platform: NodeJS.Platform;
+      channels: typeof IPC;
+      on: (channel: string, listener: (...args: unknown[]) => void) => () => void;
+      invoke: (channel: string, ...args: unknown[]) => Promise<unknown>;
+    };
+    fileRefLineScrollProbe: () => Promise<{
+      fileManagerAvailable: boolean;
+      selectedPath: string | null | undefined;
+      segments: unknown[];
+      resolveRefs: string[];
+      readPaths: string[];
+      request: { path: string; line?: number; column?: number } | null;
+      scrollCall: { line: string | undefined; block?: string } | undefined;
+      scrollTop: number;
+      targetLineVisible: boolean;
+    }>;
+  }
+}