diff --git a/packages/ui/src/components/chat/message/parts/ApplyPatchFileButtons.test.tsx b/packages/ui/src/components/chat/message/parts/ApplyPatchFileButtons.test.tsx
new file mode 100644
index 00000000..5dad5d58
--- /dev/null
+++ b/packages/ui/src/components/chat/message/parts/ApplyPatchFileButtons.test.tsx
@@ -0,0 +1,94 @@
+import { describe, expect, test } from 'bun:test';
+import React from 'react';
+import { renderToStaticMarkup } from 'react-dom/server';
+
+import type { EditorAPI } from '@/lib/api/types';
+
+import { ApplyPatchFileButtons } from './ApplyPatchFileButtons';
+import { openApplyPatchFileInEditor } from './applyPatchEditorAction';
+
+const makePatch = (path: string, line: number, before: string, after: string) => [
+    `--- a/${path}`,
+    `+++ b/${path}`,
+    `@@ -${line} +${line} @@`,
+    `-${before}`,
+    `+${after}`,
+].join('\n');
+
+const files = [
+    {
+        filePath: '/workspace/project/src/first.ts',
+        relativePath: 'src/first.ts',
+        patch: makePatch('src/first.ts', 4, 'first old', 'first new'),
+        additions: 1,
+        deletions: 1,
+        type: 'update',
+    },
+    {
+        filePath: '/workspace/project/src/second.ts',
+        relativePath: 'src/second.ts',
+        patch: makePatch('src/second.ts', 12, 'second old', 'second new'),
+        additions: 1,
+        deletions: 1,
+        type: 'update',
+    },
+];
+
+describe('ApplyPatchFileButtons', () => {
+    test('renders one labeled button per non-deleted file', () => {
+        const markup = renderToStaticMarkup(
+            <ApplyPatchFileButtons
+                metadata={{ files }}
+                openDiffLabel="Open file diff"
+                onFileClick={() => undefined}
+            />,
+        );
+
+        expect(markup.match(/<button/g)).toHaveLength(2);
+        expect(markup).toContain('aria-label="Open file diff: src/first.ts"');
+        expect(markup).toContain('aria-label="Open file diff: src/second.ts"');
+    });
+
+    test('opens each clicked file with its own authoritative path, patch, and line', () => {
+        const openDiffCalls: Parameters<EditorAPI['openDiff']>[] = [];
+        const editor: EditorAPI = {
+            openDiff: async (...args) => { openDiffCalls.push(args); },
+            openFile: async () => undefined,
+        };
+        let propagationStops = 0;
+        const stopPropagation = () => { propagationStops += 1; };
+        const tree = ApplyPatchFileButtons({
+            metadata: { files },
+            openDiffLabel: 'Open file diff',
+            onFileClick: (file, event) => {
+                event.stopPropagation();
+                const targetPath = typeof file.relativePath === 'string' ? file.relativePath : '';
+                openApplyPatchFileInEditor({
+                    currentDirectory: '/workspace/project',
+                    diffLabel: `${targetPath} (changes)`,
+                    editor,
+                    file,
+                    isVSCode: true,
+                });
+            },
+        }) as React.ReactElement<{ children: React.ReactNode }>;
+        const buttons = React.Children.toArray(tree.props.children) as React.ReactElement<{
+            onClick: (event: { stopPropagation: () => void }) => void;
+        }>[];
+
+        buttons[0]?.props.onClick({ stopPropagation });
+        buttons[1]?.props.onClick({ stopPropagation });
+
+        expect(propagationStops).toBe(2);
+        expect(openDiffCalls).toEqual([
+            ['', '/workspace/project/src/first.ts', 'src/first.ts (changes)', {
+                line: 4,
+                patch: files[0]?.patch,
+            }],
+            ['', '/workspace/project/src/second.ts', 'src/second.ts (changes)', {
+                line: 12,
+                patch: files[1]?.patch,
+            }],
+        ]);
+    });
+});
diff --git a/packages/ui/src/components/chat/message/parts/ApplyPatchFileButtons.tsx b/packages/ui/src/components/chat/message/parts/ApplyPatchFileButtons.tsx
new file mode 100644
index 00000000..b33a99ed
--- /dev/null
+++ b/packages/ui/src/components/chat/message/parts/ApplyPatchFileButtons.tsx
@@ -0,0 +1,134 @@
+import React from 'react';
+
+import { FileTypeIcon } from '@/components/icons/FileTypeIcon';
+import { Button } from '@/components/ui/button';
+import { Text } from '@/components/ui/text';
+import { cn } from '@/lib/utils';
+
+import { getApplyPatchFilePath } from './toolDiffUtils';
+
+type ApplyPatchFileEntry = {
+    file: Record<string, unknown>;
+    path: string;
+    name: string;
+    added: number | null;
+    removed: number | null;
+};
+
+const parseCount = (value: unknown): number | null => {
+    if (typeof value === 'number' && Number.isFinite(value)) {
+        return Math.max(0, Math.trunc(value));
+    }
+    if (typeof value === 'string') {
+        const parsed = Number.parseInt(value, 10);
+        return Number.isFinite(parsed) ? Math.max(0, parsed) : null;
+    }
+    return null;
+};
+
+const combineCounts = (base: number | null, incoming: number | null): number | null => {
+    if (base === null) return incoming;
+    if (incoming === null) return base;
+    return base + incoming;
+};
+
+const getApplyPatchFileEntries = (metadata: Record<string, unknown> | undefined): ApplyPatchFileEntry[] => {
+    const files = Array.isArray(metadata?.files) ? metadata.files : [];
+    const entriesByPath = new Map<string, ApplyPatchFileEntry>();
+
+    for (const file of files) {
+        if (!file || typeof file !== 'object') continue;
+        const fileRecord = file as Record<string, unknown>;
+        const displayPath = typeof fileRecord.relativePath === 'string'
+            ? fileRecord.relativePath
+            : typeof fileRecord.filePath === 'string'
+                ? fileRecord.filePath
+                : '';
+        if (!displayPath) continue;
+
+        const added = parseCount(fileRecord.additions);
+        const removed = parseCount(fileRecord.deletions);
+        const existing = entriesByPath.get(displayPath);
+        if (existing) {
+            existing.added = combineCounts(existing.added, added);
+            existing.removed = combineCounts(existing.removed, removed);
+            continue;
+        }
+
+        entriesByPath.set(displayPath, {
+            file: fileRecord,
+            path: displayPath,
+            name: displayPath.split('/').pop() || displayPath,
+            added,
+            removed,
+        });
+    }
+
+    return Array.from(entriesByPath.values());
+};
+
+export const ApplyPatchFileButtons = ({
+    animate = true,
+    metadata,
+    onFileClick,
+    openDiffLabel,
+    showFileIcons = true,
+    textClassName,
+}: {
+    animate?: boolean;
+    metadata: Record<string, unknown> | undefined;
+    onFileClick?: (file: Record<string, unknown>, event: React.MouseEvent<HTMLButtonElement>) => void;
+    openDiffLabel: string;
+    showFileIcons?: boolean;
+    textClassName?: string;
+}): React.ReactNode => {
+    const entries = getApplyPatchFileEntries(metadata);
+    if (entries.length <= 1) return null;
+
+    return (
+        <>
+            {entries.map((entry) => {
+                const hasPerFileDiff = entry.added !== null || entry.removed !== null;
+                const content = (
+                    <>
+                        {showFileIcons ? <FileTypeIcon filePath={entry.path} className="h-3.5 w-3.5" /> : null}
+                        <Text
+                            variant={animate ? 'generate-effect' : 'static'}
+                            className={cn('min-w-0 max-w-full truncate', textClassName)}
+                            style={{ color: 'var(--tools-description)' }}
+                            title={entry.path}
+                        >
+                            {entry.name}
+                        </Text>
+                        {hasPerFileDiff ? (
+                            <span className="flex-shrink-0 inline-flex items-center gap-0 typography-meta" style={{ fontSize: '0.8rem', lineHeight: '1' }}>
+                                <span style={{ color: 'var(--status-success)' }}>+{entry.added ?? 0}</span>
+                                <span style={{ color: 'var(--tools-description)' }}>/</span>
+                                <span style={{ color: 'var(--status-error)' }}>-{entry.removed ?? 0}</span>
+                            </span>
+                        ) : null}
+                    </>
+                );
+                const canOpen = onFileClick && entry.file.type !== 'delete' && getApplyPatchFilePath(entry.file);
+                const actionLabel = `${openDiffLabel}: ${entry.path}`;
+                return canOpen ? (
+                    <Button
+                        key={entry.path}
+                        variant="ghost"
+                        size="xs"
+                        className={cn('min-w-0 max-w-full gap-1 normal-case font-normal tracking-normal', textClassName)}
+                        aria-label={actionLabel}
+                        title={actionLabel}
+                        onClick={(event) => onFileClick(entry.file, event)}
+                    >
+                        {content}
+                    </Button>
+                ) : (
+                    <span key={entry.path} className={cn('inline-flex min-w-0 max-w-full items-center gap-1', textClassName)} style={{ color: 'var(--tools-description)' }}>
+                        {content}
+                    </span>
+                );
+            })}
+        </>
+    );
+};
diff --git a/packages/ui/src/components/chat/message/parts/ToolPart.tsx b/packages/ui/src/components/chat/message/parts/ToolPart.tsx
index b703c356..f62cf195 100644
--- a/packages/ui/src/components/chat/message/parts/ToolPart.tsx
+++ b/packages/ui/src/components/chat/message/parts/ToolPart.tsx
@@ -54,11 +54,22 @@ import {
 } from './taskToolModel';
 import { areRenderRelevantPartsEqual } from '../renderCompare';
 import { useI18n } from '@/lib/i18n';
-import { getDiffPatchEntries, getPatchText, type DiffPatchEntry } from './toolDiffUtils';
+import {
+    extractFirstChangedLineFromDiff,
+    getDiffPatchEntries,
+    getFirstChangedLineFromMetadata,
+    getPatchText,
+    getPrimaryDiffFromMetadata,
+    getPrimaryToolPath,
+    type DiffPatchEntry,
+} from './toolDiffUtils';
 import { isEmbeddedSessionChat } from '@/components/layout/contextPanelEmbeddedChat';
 import { useStreamingTextThrottle } from '../../hooks/useStreamingTextThrottle';
 import { getStreamingOutputAppend, getToolOutput } from './toolOutput';
+import { toAbsoluteFilePath } from '@/lib/path-utils';
 import { getToolDescriptionFallback } from './toolRenderUtils';
+import { ApplyPatchFileButtons } from './ApplyPatchFileButtons';
+import { openApplyPatchFileInEditor } from './applyPatchEditorAction';
 
 const TOOL_ROW_TEXT_CLASS = '!text-[length:var(--text-meta)] !leading-5 sm:!leading-6 tracking-normal';
 const TOOL_ROW_TITLE_CLASS = cn('typography-meta font-medium', TOOL_ROW_TEXT_CLASS);
@@ -77,84 +88,6 @@ interface ToolPartProps {
     animateTailText?: boolean;
 }
 
-const getMultiFileDescription = (
-    metadata: Record<string, unknown> | undefined,
-    animate = true,
-    showFileIcons = true,
-): React.ReactNode => {
-    const files = Array.isArray(metadata?.files) ? metadata?.files : [];
-    if (files.length <= 1) return null;
-
-    const parseCount = (value: unknown): number | null => {
-        if (typeof value === 'number' && Number.isFinite(value)) {
-            return Math.max(0, Math.trunc(value));
-        }
-        if (typeof value === 'string') {
-            const parsed = Number.parseInt(value, 10);
-            if (Number.isFinite(parsed)) {
-                return Math.max(0, parsed);
-            }
-        }
-        return null;
-    };
-
-    const combineCounts = (base: number | null, incoming: number | null): number | null => {
-        if (base === null) return incoming;
-        if (incoming === null) return base;
-        return base + incoming;
-    };
-
-    const entriesByPath = new Map<string, { path: string; name: string; added: number | null; removed: number | null }>();
-
-    for (const file of files) {
-        const fileObj = file as { relativePath?: string; filePath?: string; additions?: unknown; deletions?: unknown };
-        const filePath = fileObj.relativePath || fileObj.filePath || '';
-        if (!filePath) continue;
-        const fileName = filePath.split('/').pop() || filePath;
-        const added = parseCount(fileObj.additions);
-        const removed = parseCount(fileObj.deletions);
-
-        const existing = entriesByPath.get(filePath);
-        if (existing) {
-            existing.added = combineCounts(existing.added, added);
-            existing.removed = combineCounts(existing.removed, removed);
-            continue;
-        }
-
-        entriesByPath.set(filePath, { path: filePath, name: fileName, added, removed });
-    }
-
-    const entries = Array.from(entriesByPath.values());
-
-    return (
-        <>
-            {entries.map((entry) => {
-                const hasPerFileDiff = entry.added !== null || entry.removed !== null;
-                return (
-                    <span key={entry.path} className={cn('inline-flex min-w-0 max-w-full items-center gap-1', TOOL_ROW_DESCRIPTION_CLASS)} style={{ color: 'var(--tools-description)' }}>
-                        {showFileIcons ? <FileTypeIcon filePath={entry.path} className="h-3.5 w-3.5" /> : null}
-                        <Text
-                            variant={animate ? 'generate-effect' : 'static'}
-                            className={cn('min-w-0 max-w-full truncate', TOOL_ROW_DESCRIPTION_CLASS)}
-                            style={{ color: 'var(--tools-description)' }}
-                            title={entry.path}
-                        >
-                            {entry.name}
-                        </Text>
-                        {hasPerFileDiff ? (
-                            <span className="flex-shrink-0 inline-flex items-center gap-0 typography-meta" style={{ fontSize: '0.8rem', lineHeight: '1' }}>
-                                <span style={{ color: 'var(--status-success)' }}>+{entry.added ?? 0}</span>
-                                <span style={{ color: 'var(--tools-description)' }}>/</span>
-                                <span style={{ color: 'var(--status-error)' }}>-{entry.removed ?? 0}</span>
-                            </span>
-                        ) : null}
-                    </span>
-                );
-            })}
-        </>
-    );
-};
-
 const normalizeToolName = (toolName: string | undefined | null): string => {
     if (typeof toolName !== 'string') {
         return '';
@@ -306,54 +239,6 @@ const parseWriteLineCount = (input?: Record<string, unknown>): number | null =>
     return lines;
 };
 
-const extractFirstChangedLineFromDiff = (diffText: string): number | undefined => {
-    if (!diffText || typeof diffText !== 'string') {
-        return undefined;
-    }
-
-    const lines = diffText.split('\n');
-    let currentNewLine: number | undefined;
-    let firstHunkStart: number | undefined;
-
-    for (const rawLine of lines) {
-        const line = rawLine.replace(/\r$/, '');
-        const hunkMatch = line.match(/^@@\s+-\d+(?:,\d+)?\s+\+(\d+)(?:,\d+)?\s+@@/);
-        if (hunkMatch) {
-            const parsed = Number.parseInt(hunkMatch[1] ?? '', 10);
-            if (Number.isFinite(parsed)) {
-                currentNewLine = Math.max(1, parsed);
-                if (!Number.isFinite(firstHunkStart)) {
-                    firstHunkStart = currentNewLine;
-                }
-            }
-            continue;
-        }
-
-        if (currentNewLine === undefined || !Number.isFinite(currentNewLine)) {
-            continue;
-        }
-
-        if (line.startsWith('+++') || line.startsWith('---') || line.startsWith('diff ')) {
-            continue;
-        }
-
-        if (line.startsWith('+')) {
-            return currentNewLine;
-        }
-
-        if (line.startsWith(' ')) {
-            currentNewLine += 1;
-            continue;
-        }
-
-        if (line.startsWith('-') || line.startsWith('\\')) {
-            continue;
-        }
-    }
-
-    return firstHunkStart;
-};
-
 const buildWritePreviewPatch = (filePath: string | undefined, content: string): string | undefined => {
     const normalizedContent = content.replace(/\r\n/g, '\n');
     if (!normalizedContent.trim()) {
@@ -380,73 +265,6 @@ const buildWritePreviewPatch = (filePath: string | undefined, content: string):
     ].join('\n');
 };
 
-const getFirstChangedLineFromMetadata = (tool: string, metadata?: Record<string, unknown>): number | undefined => {
-    if (!metadata || (tool !== 'edit' && tool !== 'multiedit' && tool !== 'apply_patch')) {
-        return undefined;
-    }
-
-    const topLevelPatch = getPatchText((metadata as { patch?: unknown }).patch) ?? getPatchText(metadata.diff);
-    if (topLevelPatch) {
-        const line = extractFirstChangedLineFromDiff(topLevelPatch);
-        if (Number.isFinite(line)) {
-            return line;
-        }
-    }
-
-    const files = Array.isArray(metadata.files) ? metadata.files : [];
-    const firstFile = files[0] as { patch?: unknown; diff?: unknown } | undefined;
-    const filePatch = getPatchText(firstFile?.patch) ?? getPatchText(firstFile?.diff);
-    if (filePatch) {
-        const line = extractFirstChangedLineFromDiff(filePatch);
-        if (Number.isFinite(line)) {
-            return line;
-        }
-    }
-
-    return undefined;
-};
-
-const getPrimaryDiffFromMetadata = (
-    tool: string,
-    metadata?: Record<string, unknown>,
-    preferredPath?: string,
-): string | undefined => {
-    if (!metadata || (tool !== 'edit' && tool !== 'multiedit' && tool !== 'apply_patch')) {
-        return undefined;
-    }
-
-    const files = Array.isArray(metadata.files) ? metadata.files : [];
-    if (files.length > 0) {
-        const preferred = typeof preferredPath === 'string' && preferredPath.length > 0
-            ? preferredPath
-            : undefined;
-        const matched = preferred
-            ? files.find((file) => {
-                if (!file || typeof file !== 'object') {
-                    return false;
-                }
-                const candidate = file as { relativePath?: unknown; filePath?: unknown };
-                return candidate.relativePath === preferred || candidate.filePath === preferred;
-            })
-            : files[0];
-
-        if (matched && typeof matched === 'object') {
-            const patch = getPatchText((matched as { patch?: unknown; diff?: unknown }).patch)
-                ?? getPatchText((matched as { patch?: unknown; diff?: unknown }).diff);
-            if (patch) {
-                return patch;
-            }
-        }
-    }
-
-    const topLevelPatch = getPatchText((metadata as { patch?: unknown }).patch) ?? getPatchText(metadata.diff);
-    if (topLevelPatch) {
-        return topLevelPatch;
-    }
-
-    return undefined;
-};
-
 const normalizeDisplayPath = (value: string): string => {
     const trimmed = value.trim().replace(/\\/g, '/').replace(/\/{2,}/g, '/');
     if (!trimmed || trimmed === '/') {
@@ -526,58 +344,6 @@ const normalizeToolDiagnostic = (value: unknown): ToolDiagnostic | null => {
     };
 };
 
-const getPrimaryToolPath = (
-    toolName: string,
-    input: Record<string, unknown> | undefined,
-    metadata: Record<string, unknown> | undefined,
-): string | null => {
-    if (toolName === 'apply_patch') {
-        const files = Array.isArray(metadata?.files) ? metadata.files : [];
-        const first = files.find((entry) => {
-            if (!isRecord(entry)) {
-                return false;
-            }
-            return entry.type !== 'delete';
-        });
-        if (!isRecord(first)) {
-            return null;
-        }
-        return typeof first.movePath === 'string'
-            ? first.movePath
-            : typeof first.filePath === 'string'
-                ? first.filePath
-                : typeof first.relativePath === 'string'
-                    ? first.relativePath
-                    : null;
-    }
-
-    if (toolName === 'edit' || toolName === 'multiedit') {
-        const fileDiff = isRecord(metadata?.filediff) ? metadata.filediff : undefined;
-        if (isRecord(fileDiff) && typeof fileDiff.file === 'string') {
-            return fileDiff.file;
-        }
-        return typeof input?.filePath === 'string'
-            ? input.filePath
-            : typeof input?.file_path === 'string'
-                ? input.file_path
-                : typeof input?.path === 'string'
-                    ? input.path
-                    : null;
-    }
-
-    if (toolName === 'write') {
-        return typeof input?.filePath === 'string'
-            ? input.filePath
-            : typeof input?.file_path === 'string'
-                ? input.file_path
-                : typeof input?.path === 'string'
-                    ? input.path
-                    : null;
-    }
-
-    return null;
-};
-
 const getToolDiagnosticSection = (
     toolName: string,
     input: Record<string, unknown> | undefined,
@@ -1686,9 +1452,7 @@ const ToolExpandedContent: React.FC<ToolExpandedContentProps> = React.memo(({
     );
 
     const renderResultContent = () => {
-        const getEntryAbsolutePath = (entry: DiffPatchEntry) => (
-            entry.title.startsWith('/') ? entry.title : `${currentDirectory}/${entry.title}`.replace(/\/+/g, '/')
-        );
+        const getEntryAbsolutePath = (entry: DiffPatchEntry) => toAbsoluteFilePath(currentDirectory, entry.filePath ?? entry.title);
         const openEntryFile = (entry: DiffPatchEntry, event: React.MouseEvent<HTMLButtonElement>) => {
             event.stopPropagation();
             const line = extractFirstChangedLineFromDiff(entry.patch);
@@ -2054,6 +1818,7 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
     onShowPopup,
     animateTailText = true,
 }) => {
+    const { t } = useI18n();
     const state = part.state;
     const showToolFileIcons = useUIStore((s) => s.showToolFileIcons);
     const currentDirectory = useEffectiveDirectory() ?? '';
@@ -2347,6 +2112,26 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
     }, [descriptionPath, normalizedPartTool, stateWithData, input]);
     const runtime = React.useContext(RuntimeAPIContext);
 
+    const openApplyPatchFile = (file: Record<string, unknown>, event: React.MouseEvent<HTMLButtonElement>) => {
+        if (!runtime?.editor) {
+            return;
+        }
+
+        event.stopPropagation();
+        const displayPath = typeof file.relativePath === 'string'
+            ? file.relativePath
+            : typeof file.filePath === 'string'
+                ? getRelativePath(file.filePath, currentDirectory)
+                : '';
+        openApplyPatchFileInEditor({
+            currentDirectory,
+            diffLabel: `${displayPath} (changes)`,
+            editor: runtime.editor,
+            file,
+            isVSCode: runtime.runtime.isVSCode,
+        });
+    };
+
     const handleMainClick = (e: { stopPropagation: () => void }) => {
         if (isTaskTool || !runtime?.editor) {
             onToggle(part.id);
@@ -2356,23 +2141,21 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
         let filePath: unknown;
         let targetLine: number | undefined;
         let toolDiff: string | undefined;
-        if (part.tool === 'edit' || part.tool === 'multiedit') {
+        if (normalizedPartTool === 'edit' || normalizedPartTool === 'multiedit') {
             filePath = input?.filePath || input?.file_path || input?.path || metadata?.filePath || metadata?.file_path || metadata?.path;
-            targetLine = getFirstChangedLineFromMetadata(part.tool, metadata);
             if (typeof filePath === 'string') {
-                toolDiff = getPrimaryDiffFromMetadata(part.tool, metadata, filePath);
+                toolDiff = getPrimaryDiffFromMetadata(normalizedPartTool, metadata, filePath);
+                targetLine = getFirstChangedLineFromMetadata(normalizedPartTool, metadata, filePath);
             }
-        } else if (part.tool === 'apply_patch') {
-            const files = Array.isArray(metadata?.files) ? metadata?.files : [];
-            const firstFile = files[0] as { relativePath?: string; filePath?: string } | undefined;
-            filePath = firstFile?.relativePath || firstFile?.filePath;
-            targetLine = getFirstChangedLineFromMetadata(part.tool, metadata);
+        } else if (normalizedPartTool === 'apply_patch') {
+            filePath = getPrimaryToolPath(normalizedPartTool, input, metadata);
             if (typeof filePath === 'string') {
-                toolDiff = getPrimaryDiffFromMetadata(part.tool, metadata, filePath);
+                toolDiff = getPrimaryDiffFromMetadata(normalizedPartTool, metadata, filePath);
+                targetLine = getFirstChangedLineFromMetadata(normalizedPartTool, metadata, filePath);
             }
-        } else if (['write', 'create', 'file_write'].includes(part.tool)) {
+        } else if (['write', 'create', 'file_write'].includes(normalizedPartTool)) {
             filePath = input?.filePath || input?.file_path || input?.path || metadata?.filePath || metadata?.file_path || metadata?.path;
-        } else if (part.tool === 'lsp') {
+        } else if (normalizedPartTool === 'lsp') {
             filePath = input?.filePath || input?.file_path || input?.path;
             const line = input?.line;
             targetLine = typeof line === 'number' && Number.isFinite(line) ? Math.trunc(line) : undefined;
@@ -2380,11 +2163,8 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
 
         if (typeof filePath === 'string') {
             e.stopPropagation();
-            let absolutePath = filePath;
-            if (!filePath.startsWith('/')) {
-                absolutePath = currentDirectory.endsWith('/') ? currentDirectory + filePath : currentDirectory + '/' + filePath;
-            }
-            if (runtime.runtime.isVSCode && toolDiff && (part.tool === 'edit' || part.tool === 'multiedit' || part.tool === 'apply_patch')) {
+            const absolutePath = toAbsoluteFilePath(currentDirectory, filePath);
+            if (runtime.runtime.isVSCode && toolDiff && (normalizedPartTool === 'edit' || normalizedPartTool === 'multiedit' || normalizedPartTool === 'apply_patch')) {
                 const label = `${getRelativePath(absolutePath, currentDirectory)} (changes)`;
                 void runtime.editor.openDiff('', absolutePath, label, { line: targetLine, patch: toolDiff });
                 return;
@@ -2417,60 +2197,76 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
             {}
             <div
                 className={cn(
-                'group/tool flex gap-1.5 pr-2 pl-px py-1.5 rounded-xl cursor-pointer',
-                isMultiFileApplyPatch ? 'flex-wrap items-start' : 'items-center'
-            )}
-                onClick={handleMainClick}
-                onKeyDown={handleMainKeyDown}
-                role="button"
-                tabIndex={0}
+                    'group/tool flex gap-1.5 pr-2 pl-px py-1.5 rounded-xl',
+                    isMultiFileApplyPatch ? 'flex-wrap items-start' : 'items-center cursor-pointer',
+                )}
+                onClick={isMultiFileApplyPatch ? undefined : handleMainClick}
+                onKeyDown={isMultiFileApplyPatch ? undefined : handleMainKeyDown}
+                role={isMultiFileApplyPatch ? undefined : 'button'}
+                tabIndex={isMultiFileApplyPatch ? undefined : 0}
             >
                 <div className={cn('flex gap-1.5', isMultiFileApplyPatch ? 'w-full min-w-0 flex-wrap items-center gap-x-2 gap-y-0.5' : 'items-center flex-shrink-0')}>
-                    {}
-                    <div
-                        // h-5 matches StaticToolRow's icon column, so expandable
-                        // and static rows come out the same height (the 14px
-                        // icon alone left these rows ~2px shorter).
-                        className="relative h-5 w-3.5 flex-shrink-0 cursor-pointer"
-                        onClick={(event) => { event.stopPropagation(); onToggle(part.id); }}
-                    >
-                        {}
-                        <div
-                            className={cn(
-                                'absolute inset-0 flex items-center justify-center transition-opacity',
-                                isExpanded && 'opacity-0',
-                                !isExpanded && 'group-hover/tool:opacity-0'
-                            )}
-                            style={iconStyle}
-                        >
-                            {getToolIcon(normalizedPartTool || part.tool)}
-                        </div>
-                        {}
-                        <div
-                            className={cn(
-                                'absolute inset-0 transition-opacity flex items-center justify-center',
-                                isExpanded && 'opacity-100',
-                                !isExpanded && 'opacity-0 group-hover/tool:opacity-100'
-                            )}
-                        >
-                            {isExpanded ? <Icon name="arrow-down-s" className="h-3.5 w-3.5" /> : <Icon name="arrow-right-s" className="h-3.5 w-3.5" />}
-                        </div>
-                    </div>
                     {isMultiFileApplyPatch ? (
                         <>
-                            <MinDurationShineText
-                                active={Boolean(isActive && !isError)}
-                                minDurationMs={300}
-                                className={cn(TOOL_ROW_TITLE_CLASS, 'flex-shrink-0')}
-                                style={titleStyle}
+                            <Button
+                                variant="ghost"
+                                size="xs"
+                                className="gap-1.5 normal-case"
+                                aria-expanded={isExpanded}
+                                aria-label={displayName}
                                 title={displayName}
+                                onClick={() => onToggle(part.id)}
                             >
-                                {displayName}
-                            </MinDurationShineText>
-                            {getMultiFileDescription(metadata, animateTailText, showToolFileIcons)}
+                                {isExpanded
+                                    ? <Icon name="arrow-down-s" className="h-3.5 w-3.5" />
+                                    : getToolIcon(normalizedPartTool || part.tool)}
+                                <MinDurationShineText
+                                    active={Boolean(isActive && !isError)}
+                                    minDurationMs={300}
+                                    className={cn(TOOL_ROW_TITLE_CLASS, 'flex-shrink-0')}
+                                    style={titleStyle}
+                                >
+                                    {displayName}
+                                </MinDurationShineText>
+                            </Button>
+                            <ApplyPatchFileButtons
+                                metadata={metadata}
+                                animate={animateTailText}
+                                showFileIcons={showToolFileIcons}
+                                textClassName={TOOL_ROW_DESCRIPTION_CLASS}
+                                openDiffLabel={t('chat.toolPart.openFileDiff')}
+                                onFileClick={runtime?.editor ? openApplyPatchFile : undefined}
+                            />
                         </>
                     ) : (
                         <>
+                            <div
+                                // h-5 matches StaticToolRow's icon column, so expandable
+                                // and static rows come out the same height (the 14px
+                                // icon alone left these rows ~2px shorter).
+                                className="relative h-5 w-3.5 flex-shrink-0 cursor-pointer"
+                                onClick={(event) => { event.stopPropagation(); onToggle(part.id); }}
+                            >
+                                <div
+                                    className={cn(
+                                        'absolute inset-0 flex items-center justify-center transition-opacity',
+                                        isExpanded && 'opacity-0',
+                                        !isExpanded && 'group-hover/tool:opacity-0'
+                                    )}
+                                    style={iconStyle}
+                                >
+                                    {getToolIcon(normalizedPartTool || part.tool)}
+                                </div>
+                                <div
+                                    className={cn(
+                                        'absolute inset-0 transition-opacity flex items-center justify-center',
+                                        isExpanded && 'opacity-100',
+                                        !isExpanded && 'opacity-0 group-hover/tool:opacity-100'
+                                    )}
+                                >
+                                    {isExpanded ? <Icon name="arrow-down-s" className="h-3.5 w-3.5" /> : <Icon name="arrow-right-s" className="h-3.5 w-3.5" />}
+                                </div>
+                            </div>
                             <div className="flex items-center gap-2 min-w-0 flex-1">
                                 <MinDurationShineText
                                     active={Boolean(isActive && !isError)}
diff --git a/packages/ui/src/components/chat/message/parts/applyPatchEditorAction.ts b/packages/ui/src/components/chat/message/parts/applyPatchEditorAction.ts
new file mode 100644
index 00000000..4b5d19d2
--- /dev/null
+++ b/packages/ui/src/components/chat/message/parts/applyPatchEditorAction.ts
@@ -0,0 +1,33 @@
+import type { EditorAPI } from '@/lib/api/types';
+import { toAbsoluteFilePath } from '@/lib/path-utils';
+
+import { extractFirstChangedLineFromDiff, getApplyPatchFilePath, getPatchText } from './toolDiffUtils';
+
+export const openApplyPatchFileInEditor = ({
+    currentDirectory,
+    diffLabel,
+    editor,
+    file,
+    isVSCode,
+}: {
+    currentDirectory: string;
+    diffLabel: string;
+    editor: EditorAPI;
+    file: Record<string, unknown>;
+    isVSCode: boolean;
+}): boolean => {
+    const filePath = getApplyPatchFilePath(file);
+    if (!filePath || file.type === 'delete') {
+        return false;
+    }
+
+    const patch = getPatchText(file.patch) ?? getPatchText(file.diff);
+    const line = patch ? extractFirstChangedLineFromDiff(patch) : undefined;
+    const absolutePath = toAbsoluteFilePath(currentDirectory, filePath);
+    if (isVSCode && patch) {
+        void editor.openDiff('', absolutePath, diffLabel, { line, patch });
+    } else {
+        void editor.openFile(absolutePath, line);
+    }
+    return true;
+};
diff --git a/packages/ui/src/components/chat/message/parts/toolDiffUtils.test.ts b/packages/ui/src/components/chat/message/parts/toolDiffUtils.test.ts
index 58929c5d..cc69096e 100644
--- a/packages/ui/src/components/chat/message/parts/toolDiffUtils.test.ts
+++ b/packages/ui/src/components/chat/message/parts/toolDiffUtils.test.ts
@@ -1,10 +1,87 @@
 import { describe, expect, test } from 'bun:test';
 
-import { getDiffPatchEntries, getRenderablePatchInfo } from './toolDiffUtils';
+import {
+    getApplyPatchFilePath,
+    getDiffPatchEntries,
+    getFirstChangedLineFromMetadata,
+    getPrimaryDiffFromMetadata,
+    getPrimaryToolPath,
+    getRenderablePatchInfo,
+} from './toolDiffUtils';
 
 const identity = (path: string) => path;
 
 describe('toolDiffUtils', () => {
+    test('prefers the absolute apply_patch path over its worktree-relative label', () => {
+        expect(getPrimaryToolPath('apply_patch', undefined, {
+            files: [{
+                filePath: '/workspace/project/src/file.ts',
+                relativePath: 'workspace/project/src/file.ts',
+                type: 'update',
+            }],
+        })).toBe('/workspace/project/src/file.ts');
+    });
+
+    test('opens the move destination and skips deleted apply_patch files', () => {
+        expect(getPrimaryToolPath('apply_patch', undefined, {
+            files: [
+                { filePath: '/workspace/deleted.ts', relativePath: 'deleted.ts', type: 'delete' },
+                {
+                    filePath: '/workspace/old.ts',
+                    relativePath: 'new.ts',
+                    movePath: '/workspace/new.ts',
+                    type: 'move',
+                },
+            ],
+        })).toBe('/workspace/new.ts');
+    });
+
+    test('falls back to the relative apply_patch path for legacy metadata', () => {
+        expect(getPrimaryToolPath('apply_patch', undefined, {
+            files: [{ relativePath: 'src/file.ts', type: 'update' }],
+        })).toBe('src/file.ts');
+    });
+
+    test('resolves each apply_patch file independently', () => {
+        expect(getApplyPatchFilePath({
+            filePath: '/workspace/project/src/first.ts',
+            relativePath: 'workspace/project/src/first.ts',
+        })).toBe('/workspace/project/src/first.ts');
+        expect(getApplyPatchFilePath({
+            filePath: '/workspace/project/src/old.ts',
+            movePath: '/workspace/project/src/second.ts',
+            relativePath: 'src/second.ts',
+        })).toBe('/workspace/project/src/second.ts');
+    });
+
+    test('selects the move patch and line from the same non-deleted file', () => {
+        const deletedPatch = '@@ -3 +3 @@\n-old\n+deleted';
+        const movedPatch = '@@ -42 +42 @@\n-before\n+after';
+        const metadata = {
+            patch: deletedPatch,
+            files: [
+                {
+                    filePath: '/workspace/project/src/deleted.ts',
+                    relativePath: 'src/deleted.ts',
+                    patch: deletedPatch,
+                    type: 'delete',
+                },
+                {
+                    filePath: '/workspace/project/src/old.ts',
+                    movePath: '/workspace/project/src/moved.ts',
+                    relativePath: 'src/moved.ts',
+                    patch: movedPatch,
+                    type: 'move',
+                },
+            ],
+        };
+
+        expect(getPrimaryDiffFromMetadata('apply_patch', metadata, '/workspace/project/src/moved.ts'))
+            .toBe(movedPatch);
+        expect(getFirstChangedLineFromMetadata('apply_patch', metadata, '/workspace/project/src/moved.ts'))
+            .toBe(42);
+    });
+
     test('treats raw apply_patch envelopes as text, not visual diffs', () => {
         const entries = getDiffPatchEntries(undefined, [
             '*** Begin Patch',
@@ -57,6 +134,27 @@ describe('toolDiffUtils', () => {
         expect(entries[0]?.title).toBe('src/file.ts');
     });
 
+    test('keeps the authoritative path for every metadata file entry', () => {
+        const patch = [
+            '--- a/src/file.ts',
+            '+++ b/src/file.ts',
+            '@@ -1 +1 @@',
+            '-old',
+            '+new',
+        ].join('\n');
+        const entries = getDiffPatchEntries({
+            files: [
+                { filePath: '/workspace/project/src/first.ts', relativePath: 'src/first.ts', patch },
+                { filePath: '/workspace/project/src/second.ts', relativePath: 'src/second.ts', patch },
+            ],
+        }, undefined, identity);
+
+        expect(entries.map((entry) => entry.filePath)).toEqual([
+            '/workspace/project/src/first.ts',
+            '/workspace/project/src/second.ts',
+        ]);
+    });
+
     test('synthesizes headers for valid headerless hunks', () => {
         const entries = getDiffPatchEntries(undefined, [
             '@@ -1 +1 @@',
diff --git a/packages/ui/src/components/chat/message/parts/toolDiffUtils.ts b/packages/ui/src/components/chat/message/parts/toolDiffUtils.ts
index 23d9aac0..5bbe2efb 100644
--- a/packages/ui/src/components/chat/message/parts/toolDiffUtils.ts
+++ b/packages/ui/src/components/chat/message/parts/toolDiffUtils.ts
@@ -3,6 +3,7 @@ import { parsePatchFiles } from '@pierre/diffs';
 export type DiffPatchEntry = {
     id: string;
     title: string;
+    filePath?: string;
     patch: string;
     renderMode: 'diff' | 'text';
 };
@@ -140,6 +141,172 @@ export const getPatchText = (value: unknown): string | undefined => {
     return undefined;
 };
 
+export const getApplyPatchFilePath = (file: unknown): string | null => {
+    if (!isRecord(file)) {
+        return null;
+    }
+
+    return typeof file.movePath === 'string'
+        ? file.movePath
+        : typeof file.filePath === 'string'
+            ? file.filePath
+            : typeof file.relativePath === 'string'
+                ? file.relativePath
+                : null;
+};
+
+export const getPrimaryToolPath = (
+    toolName: string,
+    input: Record<string, unknown> | undefined,
+    metadata: Record<string, unknown> | undefined,
+): string | null => {
+    if (toolName === 'apply_patch') {
+        const files = Array.isArray(metadata?.files) ? metadata.files : [];
+        for (const file of files) {
+            if (isRecord(file) && file.type !== 'delete') {
+                const filePath = getApplyPatchFilePath(file);
+                if (filePath) {
+                    return filePath;
+                }
+            }
+        }
+        return null;
+    }
+
+    if (toolName === 'edit' || toolName === 'multiedit') {
+        const fileDiff = isRecord(metadata?.filediff) ? metadata.filediff : undefined;
+        if (fileDiff && typeof fileDiff.file === 'string') {
+            return fileDiff.file;
+        }
+        return typeof input?.filePath === 'string'
+            ? input.filePath
+            : typeof input?.file_path === 'string'
+                ? input.file_path
+                : typeof input?.path === 'string'
+                    ? input.path
+                    : null;
+    }
+
+    if (toolName === 'write') {
+        return typeof input?.filePath === 'string'
+            ? input.filePath
+            : typeof input?.file_path === 'string'
+                ? input.file_path
+                : typeof input?.path === 'string'
+                    ? input.path
+                    : null;
+    }
+
+    return null;
+};
+
+const supportsDiffMetadata = (toolName: string): boolean => (
+    toolName === 'edit' || toolName === 'multiedit' || toolName === 'apply_patch'
+);
+
+const getMetadataFileForPath = (
+    metadata: Record<string, unknown>,
+    preferredPath?: string,
+): Record<string, unknown> | undefined => {
+    const files = Array.isArray(metadata.files) ? metadata.files : [];
+    if (!preferredPath) {
+        const first = files[0];
+        return isRecord(first) ? first : undefined;
+    }
+
+    return files.find((file): file is Record<string, unknown> => (
+        isRecord(file)
+        && (file.relativePath === preferredPath || file.filePath === preferredPath || file.movePath === preferredPath)
+    ));
+};
+
+export const getPrimaryDiffFromMetadata = (
+    toolName: string,
+    metadata?: Record<string, unknown>,
+    preferredPath?: string,
+): string | undefined => {
+    if (!metadata || !supportsDiffMetadata(toolName)) {
+        return undefined;
+    }
+
+    const matchedFile = getMetadataFileForPath(metadata, preferredPath);
+    const filePatch = getPatchText(matchedFile?.patch) ?? getPatchText(matchedFile?.diff);
+    if (filePatch) {
+        return filePatch;
+    }
+
+    return getPatchText(metadata.patch) ?? getPatchText(metadata.diff);
+};
+
+export const extractFirstChangedLineFromDiff = (diffText: string): number | undefined => {
+    if (!diffText) {
+        return undefined;
+    }
+
+    let currentNewLine: number | undefined;
+    let firstHunkStart: number | undefined;
+    for (const rawLine of diffText.split('\n')) {
+        const line = rawLine.replace(/\r$/, '');
+        const hunkMatch = line.match(/^@@\s+-\d+(?:,\d+)?\s+\+(\d+)(?:,\d+)?\s+@@/);
+        if (hunkMatch) {
+            const parsed = Number.parseInt(hunkMatch[1] ?? '', 10);
+            if (Number.isFinite(parsed)) {
+                currentNewLine = Math.max(1, parsed);
+                firstHunkStart ??= currentNewLine;
+            }
+            continue;
+        }
+
+        if (currentNewLine === undefined) {
+            continue;
+        }
+        if (line.startsWith('+++') || line.startsWith('---') || line.startsWith('diff ')) {
+            continue;
+        }
+        if (line.startsWith('+')) {
+            return currentNewLine;
+        }
+        if (line.startsWith(' ')) {
+            currentNewLine += 1;
+        }
+    }
+
+    return firstHunkStart;
+};
+
+export const getFirstChangedLineFromMetadata = (
+    toolName: string,
+    metadata?: Record<string, unknown>,
+    preferredPath?: string,
+): number | undefined => {
+    if (!metadata || !supportsDiffMetadata(toolName)) {
+        return undefined;
+    }
+
+    if (preferredPath) {
+        const matchedFile = getMetadataFileForPath(metadata, preferredPath);
+        const matchedPatch = getPatchText(matchedFile?.patch) ?? getPatchText(matchedFile?.diff);
+        if (matchedPatch) {
+            const matchedLine = extractFirstChangedLineFromDiff(matchedPatch);
+            if (matchedLine !== undefined) {
+                return matchedLine;
+            }
+        }
+    }
+
+    const topLevelPatch = getPatchText(metadata.patch) ?? getPatchText(metadata.diff);
+    if (topLevelPatch) {
+        const topLevelLine = extractFirstChangedLineFromDiff(topLevelPatch);
+        if (topLevelLine !== undefined) {
+            return topLevelLine;
+        }
+    }
+
+    const firstFile = getMetadataFileForPath(metadata);
+    const firstPatch = getPatchText(firstFile?.patch) ?? getPatchText(firstFile?.diff);
+    return firstPatch ? extractFirstChangedLineFromDiff(firstPatch) : undefined;
+};
+
 const normalizeParsedPath = (path: string | undefined): string => {
     const trimmed = (path ?? '').trim().replace(/\t.*$/, '');
     if (!trimmed || trimmed === '/dev/null') {
@@ -287,7 +454,7 @@ const getPatchEntriesFromText = (
     }];
 };
 
-const getFilePatch = (file: unknown): { patch: string; title: string } | null => {
+const getFilePatch = (file: unknown): { filePath?: string; patch: string; title: string } | null => {
     if (!isRecord(file)) {
         return null;
     }
@@ -304,6 +471,7 @@ const getFilePatch = (file: unknown): { patch: string; title: string } | null =>
             : '';
 
     return {
+        filePath: getApplyPatchFilePath(file) ?? undefined,
         patch,
         title: rawPath,
     };
@@ -325,7 +493,7 @@ export const getDiffPatchEntries = (
             filePatch.title || `File ${index + 1}`,
             `file-${index}`,
             resolveTitle,
-        );
+        ).map((entry) => ({ ...entry, filePath: filePatch.filePath }));
     });
 
     if (fileEntries.length > 0) {