Improve copying chat output to external apps

[lramos15]

Fix #328212

[Copilot]

Pull request overview

Improves chat output portability when copying to external applications and reduces incorrect file/symbol links.

Changes:

• Converts local/internal links and images to inline code during copy or paste.
• Adds reusable Markdown link rewriting and copy sanitization.
• Avoids ambiguous or false-positive Copilot linkification.

Show a summary per file

File	Description
src/vs/workbench/contrib/chat/test/common/model/chatModel.test.ts	Tests portable inline references.
src/vs/workbench/contrib/chat/test/browser/widget/chatClipboard.test.ts	Tests clipboard sanitization.
src/vs/workbench/contrib/chat/test/browser/widget/__snapshots__/ChatMarkdownRenderer_supportHtml_with_one-line_markdown.1.snap	Updates external-link rendering snapshot.
src/vs/workbench/contrib/chat/common/model/chatModel.ts	Formats file references as code.
src/vs/workbench/contrib/chat/browser/widget/chatListWidget.ts	Sanitizes rich-text copy selections.
src/vs/workbench/contrib/chat/browser/widget/chatClipboard.ts	Implements portable HTML and Markdown conversion.
src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/stateToProgressAdapter.ts	Reuses Markdown rewriting utility.
src/vs/workbench/contrib/chat/browser/actions/chatCopyActions.ts	Sanitizes chat copy actions.
src/vs/base/test/common/markdownLinks.test.ts	Tests source-aware link rewriting.
src/vs/base/test/browser/markdownRenderer.test.ts	Tests copy-safe rendered links.
src/vs/base/test/browser/htmlToMarkdown.test.ts	Tests internal-link conversion.
src/vs/base/common/markdownLinks.ts	Adds Markdown rewriting infrastructure.
src/vs/base/common/htmlContent.ts	Classifies portable link targets.
src/vs/base/browser/markdownRenderer.ts	Restores safe external href values.
src/vs/base/browser/htmlToMarkdown.ts	Converts internal HTML links to code.
extensions/copilot/src/extension/linkify/vscode-node/symbolLinkifier.ts	Rejects ambiguous symbol resources.
extensions/copilot/src/extension/linkify/vscode-node/findWord.ts	Tightens qualified-symbol matching.
extensions/copilot/src/extension/linkify/vscode-node/findSymbol.ts	Parses qualified symbol names.
extensions/copilot/src/extension/linkify/test/vscode-node/findSymbol.test.ts	Tests qualified-name parsing.
extensions/copilot/src/extension/linkify/test/node/util.ts	Adds multi-root test setup.
extensions/copilot/src/extension/linkify/test/node/filePathLinkifier.spec.ts	Tests false-positive and ambiguous paths.
extensions/copilot/src/extension/linkify/common/modelFilePathLinkifier.ts	Rejects ambiguous model paths.
extensions/copilot/src/extension/linkify/common/linkifiedText.ts	Adds single-resource matching.
extensions/copilot/src/extension/linkify/common/filePathLinkifier.ts	Tightens file and directory linkification.

Review details

Suppressed comments (1)

src/vs/workbench/contrib/chat/browser/widget/chatClipboard.ts:115

• This fallback searches the entire source for every matching destination, including code spans and fenced blocks. When an unlocatable multiline link shares a target with a literal example in code, both occurrences are changed to ](), contradicting the helper's guarantee that code remains byte-for-byte intact. Exclude matches overlapping codeRanges.

				for (let at = source.indexOf(`](${target})`); at >= 0; at = source.indexOf(`](${target})`, at + 1)) {
					edits.push({ start: at, end: at + `](${target})`.length, replacement: ']()' });
				}

• Files reviewed: 24/24 changed files
• Comments generated: 4
• Review effort level: Balanced

[github-actions]

Base: 5d8fefff Current: ae1d6f87

No screenshot changes.

[Copilot]

Review details

Suppressed comments (6)

src/vs/base/common/markdownLinks.ts:139

• findDefinitionRanges only examines gaps between top-level tokens. Marked can consume a reference definition inside a blockquote or list item within the enclosing token's raw, so that definition is never reported here. For example, > [x][r]\n>\n> [r]: /Users/me/private.ts rewrites the reference but leaves the private definition on the clipboard. Definition discovery needs to account for nested container source ranges while still excluding code.

function findDefinitionRanges(tokens: readonly marked.Token[], markdown: string): { start: number; end: number }[] {
	const ranges: { start: number; end: number }[] = [];
	let cursor = 0;
	for (const token of tokens) {

src/vs/workbench/contrib/chat/browser/widget/chatClipboard.ts:113

• This fallback assumes the destination appears exactly as ](${target}), but token.href is parser-normalized and omits source syntax such as angle brackets, escapes, and titles. An unlocatable link such as a multiline blockquote label followed by (/Users/me/a.ts "title") is therefore left unchanged and still exposes the local path. Locate the original destination suffix/range rather than synthesizing it from href.

				const needle = `](${target})`;
				for (let at = source.indexOf(needle); at >= 0; at = source.indexOf(needle, at + 1)) {
					if (!overlapsCode(at, at + needle.length, codeRanges)) {
						edits.push({ start: at, end: at + needle.length, replacement: ']()' });
					}
				}

src/vs/workbench/contrib/chat/browser/widget/chatClipboard.ts:92

• These parser-decoded fields are interpolated back into Markdown without escaping. For example, a portable reference label such as [a\]b][r] loses its source escape and becomes malformed [a]b](https://...); escaped quotes in a definition title have the same problem. Serialize the label, destination, and title with Markdown-safe escaping instead of inserting normalized token fields directly.

			if (!token.raw.includes(target)) {
				const title = token.title ? ` "${token.title}"` : '';
				return `${token.type === 'image' ? '!' : ''}[${token.text}](${target}${title})`;

src/vs/base/common/markdownLinks.ts:104

• When an opaque code token cannot be located, it is silently skipped and never added to codeRanges. This occurs for fenced code nested in a blockquote because marked strips the > prefixes from the child token's raw; the caller's fallback source scan can then rewrite a matching ](local-path) inside that fence. Track unlocatable code regions or avoid source-wide fallback edits so code remains byte-for-byte intact as promised.

This issue also appears on line 136 of the same file.

		const start = markdown.indexOf(raw, cursor);
		if (start < 0) {
			if (token.type === 'link' || token.type === 'image') {
				unlocatable.push(token as marked.Tokens.Link | marked.Tokens.Image);
			}
			continue;

src/vs/workbench/contrib/chat/browser/widget/chatClipboard.ts:119

• Dropping every definition breaks portable reference links whose token could not be located. A multiline reference label inside a blockquote/list is added to unlocatable; its https target is intentionally not scrubbed, but this line still deletes the definition, leaving an unresolved literal reference after copy. Preserve definitions that are still needed by unlocatable portable links.

			// A definition holds its target in source the reader never saw, so leaving one behind
			// would publish the very path this strips. The links that leaned on them now spell
			// their targets out, so the definitions have nothing left to say.
			edits.push(...definitionRanges.map(range => ({ ...range, replacement: '' })));

extensions/copilot/src/extension/linkify/common/linkifiedText.ts:54

• Using Uri.toString() makes the uniqueness check path-case-sensitive. On case-insensitive file systems, candidates or references that differ only in path casing identify the same file but are treated as ambiguous, so linkification is incorrectly suppressed. Use a platform-appropriate comparison key from extensions/copilot/src/util/vs/base/common/resources.ts (see extUriBiasedIgnorePathCase at lines 342-345).

	return new Set(matches.map(match => match.toString())).size === 1 ? matches[0] : undefined;

• Files reviewed: 24/24 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[garretwilson]

I appreciate the work done to address this issue. At first I wasn't sure why it was so large, but a review indicated that it touches when chat text is turned into links, how those links are rendered, and how they are converted during copy and paste. I did an independent review (which was quite extensive):

PR #328466 is a sound, well-tested solution that correctly addresses #328212 through complementary copy-time and paste-time sanitization while preserving legitimate external links. Its broader linkification changes also resolve several concrete false positives and multi-root ambiguities, although they remain distributed heuristics rather than a unified inference policy. The only definite defect is a narrow, easily fixed case where an image nested inside a non-portable link is discarded along with its alt text. The PR is already merged and unreleased in milestone 1.133.0, so that correction is worth taking before it ships; its main weakness is that the description understates its substantially broader scope.

As mentioned there was one bug that cropped up. I provide it below, courtesy of Claude Open 5 (in conjunction with GPT-5 Sol). Otherwise they tell me this looks good — thanks!

---

Bug: Nested images inside non-portable links are dropped entirely.

toPortableMarkdown deliberately keeps the alt text in this case, and there's a test for it:

toPortableMarkdown('[![img](/i.png)](/repo/a.ts)')   //  '`img`'

The two HTML paths added here don't. Both derive the replacement label from textContent, which is empty for an image, so the anchor looks contentless and the whole subtree is discarded:

// src/vs/base/test/browser/htmlToMarkdown.test.ts
convertHtmlToMarkdown('<a href="file:///repo/a.ts"><img alt="diagram" src="https://example.com/d.png"></a>')
// actual:   ''
// expected: '![diagram](https://example.com/d.png)'

// src/vs/workbench/contrib/chat/test/browser/widget/chatClipboard.test.ts
sanitizeToHtml('<a href="" data-href="file:///repo/a.ts"><img alt="diagram" src="https://example.com/d.png"></a>')
// actual:   ''
// expected: '<img alt="diagram" src="https://example.com/d.png">'

Note the image target is portable in both cases — a shareable https image is destroyed because of the wrapper around it. With a non-portable image, the alt text is lost instead.

In sanitizeLink, text already holds the converted children, and the javascript:/vbscript:/data: branch above returns it for the same reason:

if (!target || !isPortableMarkdownTarget(target)) {
    return plainText ? appendEscapedMarkdownInlineCode(plainText) : text;
}

In replaceWithLabel, unwrapping rather than removing lets the image loop handle the freed node:

if (!label.trim()) {
    element.replaceWith(...element.childNodes);
    return;
}

Neither breaks an existing test — an empty anchor has no children, so replaceWith() is equivalent to remove(). One pre-existing quirk becomes visible in one more place: convertChildren renders an empty <strong></strong> as ****, which convertHtmlToMarkdown('<strong></strong>') already produces today.

Narrow in practice, since chat disallows remote images and browsers usually resolve hrefs before the clipboard — the realistic trigger is pasting from a local HTML file or the markdown preview.

[garretwilson]

Here is a status of how this PR relates to other ticket, courtesy of Claude Opus 5 (with the help of GPT-5.6 Sol):

---

Link-issue status after PR #328466

As of 2026-08-05. PR merged, milestone 1.133.0, not yet released.
Only #328212 was declared. Two further issues are fixed in code but still open.

Fixed by this PR

Issue	Subject	GitHub state	Where the fix is
#328212	vscode-file://vscode-app links on paste	Closed	sanitizeChatClipboardFragment rewrites anchors at copy time; linkTargetOf + sanitizeLink in htmlToMarkdown.ts catch them at paste time
#313539	Ordinary https links lose their href on rich copy	Open	rewriteRenderedLinks in markdownRenderer.ts now restores href for http/https/mailto instead of blanking it
#312422	Rich copy emits non-functional vscode:// URIs	Open	Non-portable anchors become <code> in the copied HTML, so the URIs never reach the clipboard

Both open entries are candidates for closing, or at least for verification against
this build. Community PR #313540 was opened against #313539 and is likely superseded.

Narrowed, still open

Issue	Subject	Where the change is
#280165	Auto-linking breaks copy-paste to external systems	The copy/paste half is fixed as above. looksLikePath in filePathLinkifier.ts stops bare words like web and FooBar linking to same-named folders; extractQualifiedSymbolParts in findSymbol.ts stops mx:text resolving to an unrelated symbol
#292748	sed -i, .gitignore, **/Filename.java linkified	Closed earlier as a duplicate. Its exact strings are now regression tests in findSymbol.test.ts — they no longer become symbol links

Contained, not fixed

Issue	Subject	What changed
#272350	http://_vscodecontentref_/N links	The placeholderAuthority check in htmlContent.ts stops these escaping into copied or pasted content. They are still generated and still rendered in chat, so the issue stands

Partially addressed

Issue	Subject	What changed
#297792	Links to the wrong file in a multi-root workspace	singleMatch in linkifiedText.ts, used by all three linkifiers, refuses to link a path that resolves in more than one root rather than taking the first. The class of bug is addressed; the exact reported scenario has no test

Untouched

Issue	Subject	Why
#290382	Relative path with line anchor fails to open	This is a click-time resolution failure. The PR changes link creation, rendering, and export, but not resolution

Pattern

Links leaking out broken is now handled comprehensively. Links existing when they
shouldn't is narrowed case by case, not solved. #290382 is unaffected because it is
the inverse problem: a legitimate link that fails to open.

Open defect in this PR

An image nested inside a non-portable link is discarded along with its alt text, in
both htmlToMarkdown.ts and chatClipboard.ts. toPortableMarkdown handles the
same structure correctly and has a passing test for it. Two-line fix, worth taking
before 1.133 ships.