fix(app): open explicit file links regardless of extension (#7233)

Authored Markdown destinations were filtered by the filename heuristics intended for inferred text, silently ignoring screenshot links. Resolve explicit destinations directly through the existing workspace opener so reads and failures reach the file pane.

packages/app/e2e/browser/file-editing.spec.ts

@@ -105,6 +105,37 @@ async function seedAgentWithFileLink(input: LinkedFile) {
 }
 
 test.describe("CodeMirror workspace file editing", () => {
+  test("opens explicit screenshot links and explains missing files", async ({ page }) => {
+    const session = await seedMockAgentWorkspace({
+      repoPrefix: "screenshot-markdown-link-",
+      title: "Screenshot file links",
+      initialPrompt: "Show screenshots",
+      featureValues: {
+        mockAssistantResponse:
+          "[Capture](.dev/tablet-review/capture.png) [Missing capture](.dev/tablet-review/missing.png)",
+      },
+    });
+    try {
+      await mkdir(path.join(session.cwd, ".dev/tablet-review"), { recursive: true });
+      await writeFile(path.join(session.cwd, ".dev/tablet-review/capture.png"), RED_PIXEL);
+      await openAgentRoute(page, session);
+      await test.step("Open the linked screenshot", async () => {
+        await openAssistantMarkdownLink(page, "Capture");
+        await expectFileTabOpen(page, ".dev/tablet-review/capture.png");
+        await expect(page.getByTestId("image-file-preview-canvas")).toBeVisible();
+      });
+      await test.step("Explain why the missing screenshot cannot open", async () => {
+        await returnToAssistant(page, session.agentId);
+        await openAssistantMarkdownLink(page, "Missing capture");
+        await expectFileTabOpen(page, ".dev/tablet-review/missing.png");
+        await expect(page.getByText(/ENOENT/)).toBeVisible();
+        await expect(page.getByRole("button", { name: "Retry", exact: true })).toBeVisible();
+      });
+    } finally {
+      await session.cleanup();
+    }
+  });
+
   test("opens the non-ASCII file named by an assistant markdown link", async ({ page }) => {
     const session = await seedMockAgentWorkspace({
       repoPrefix: "encoded-markdown-link-",

packages/app/src/assistant-file-links/parse.ts

@@ -23,6 +23,8 @@ const INLINE_PAREN_LINE_SUFFIX = /^(.+?)\(([0-9]+)(?:,[0-9]+)?(?:-([0-9]+)(?:,[0
 const INLINE_WORD_LINE_SUFFIX = /^(.+?)\s+lines?\s+([0-9]+)(?:-([0-9]+))?$/i;
 export interface AssistantHrefParseOptions {
   workspaceRoot?: string;
+  /** Authored links identify a file; only inferred text needs filename heuristics. */
+  explicitLink?: boolean;
   /**
    * True only when `value` is a markdown href — the renderer percent-encodes
    * non-ASCII and space characters, so the path must be decoded. Raw path
@@ -30,8 +32,6 @@ export interface AssistantHrefParseOptions {
    * send a real file named `my%20file.md` to `my file.md`.
    */
   decodeHref?: boolean;
-  /** Explicit Markdown links can name nested folders without a filename extension. */
-  allowExtensionlessNestedPaths?: boolean;
 }
 
 export type AssistantFileLinkClassification =
@@ -236,7 +236,7 @@ export function classifyAssistantFileLink(
     return null;
   }
 
-  if (isAmbiguousWorkspaceCandidate(trimmed, target, options)) {
+  if (!options.explicitLink && isAmbiguousWorkspaceCandidate(trimmed, target, options)) {
     return {
       kind: "ambiguousFileCandidate",
       target,
@@ -280,7 +280,7 @@ export function parseAssistantFileLink(
   const relativeTarget = parseWorkspaceRelativeFileLink(trimmed, {
     workspaceRoot: options.workspaceRoot,
     decodeHref: options.decodeHref,
-    allowExtensionlessNestedPaths: options.allowExtensionlessNestedPaths,
+    explicitLink: options.explicitLink,
   });
   if (relativeTarget) {
     return relativeTarget;
@@ -414,7 +414,7 @@ function parseWorkspaceRelativeFileLink(
 
 function parseLocalPathParts(
   value: string,
-  options: Pick<AssistantHrefParseOptions, "decodeHref" | "allowExtensionlessNestedPaths"> = {},
+  options: Pick<AssistantHrefParseOptions, "decodeHref" | "explicitLink"> = {},
 ): {
   path: string;
   lines: Pick<InlinePathTarget, "lineStart" | "lineEnd">;
@@ -440,7 +440,7 @@ function parseLocalPathParts(
     if (options.decodeHref) {
       pathPart = safeDecodeURIComponent(pathPart);
     }
-    if (!isPlausibleAssistantLocalPath(pathPart, options)) {
+    if (!options.explicitLink && !isPlausibleAssistantLocalPath(pathPart)) {
       return null;
     }
     return {
@@ -461,7 +461,7 @@ function parseLocalPathParts(
     decodedBeforeHash = safeDecodeURIComponent(beforeHash);
   }
   const plausiblePath = parseInlinePathToken(decodedBeforeHash)?.path ?? decodedBeforeHash;
-  if (!isPlausibleAssistantLocalPath(plausiblePath, options)) {
+  if (!options.explicitLink && !isPlausibleAssistantLocalPath(plausiblePath)) {
     return null;
   }
 
@@ -586,10 +586,7 @@ function getHeuristicLocalPath(value: string): string | null {
   return beforeHash;
 }
 
-function isPlausibleAssistantLocalPath(
-  pathValue: string,
-  options: Pick<AssistantHrefParseOptions, "allowExtensionlessNestedPaths"> = {},
-): boolean {
+function isPlausibleAssistantLocalPath(pathValue: string): boolean {
   const normalized = normalizePathToken(pathValue);
   if (!normalized) {
     return false;
@@ -613,10 +610,7 @@ function isPlausibleAssistantLocalPath(
 
   if (segments.length > 1) {
     const lastSegment = segments[segments.length - 1];
-    return (
-      !isDomainLikePathSegment(firstSegment) &&
-      (options.allowExtensionlessNestedPaths === true || isPlausibleAssistantFileName(lastSegment))
-    );
+    return !isDomainLikePathSegment(firstSegment) && isPlausibleAssistantFileName(lastSegment);
   }
 
   return isPlausibleAssistantFileName(firstSegment);

packages/app/src/assistant-file-links/resolver.test.ts

@@ -50,7 +50,7 @@ it.each([{ markup: "linkify" }, { sourceInfo: "auto" }])(
   },
 );
 
-it.each(["example.com/guides", "docs/guides?view=all"])(
+it.each(["docs/guides?view=all"])(
   "does not turn URL-like hrefs into workspace paths: %s",
   (href) => {
     expect(classifyForResolution({ href }, CONTEXT)).toEqual({
@@ -60,6 +60,21 @@ it.each(["example.com/guides", "docs/guides?view=all"])(
   },
 );
 
+it.each([
+  ".dev/tablet-review/tablet-agent-draft.png",
+  "images/capture.jpg",
+  "downloads/archive.custom",
+  "assets/LICENSE",
+  "example.com/guides",
+  "capture.png",
+  "missing.png",
+])("opens explicit file link %s without filename guessing", (href) => {
+  expect(classifyForResolution({ href }, CONTEXT)).toMatchObject({
+    kind: "resolved",
+    value: { kind: "file", target: { path: `${CONTEXT.workspaceRoot}/${href}` } },
+  });
+});
+
 it("opens the existing non-ASCII file named by a rendered markdown link", async () => {
   const workspaceRoot = await mkdtemp(path.join(tmpdir(), "assistant-file-link-"));
   try {

packages/app/src/assistant-file-links/resolver.ts

@@ -117,7 +117,7 @@ export function classifyForResolution(
   const classification = classifyAssistantFileLink(token, {
     workspaceRoot: context.workspaceRoot,
     decodeHref: tokenInfo.fromHref,
-    allowExtensionlessNestedPaths: tokenInfo.fromHref && !isLinkifiedSource(source),
+    explicitLink: source.sourceType !== "inline-code" && !isLinkifiedSource(source),
   });
   if (!classification) {
     return { kind: "resolved", value: { kind: "ignored" } };