fix(files): open file paths agents print, from the terminal and the chat

A path an agent prints was already underlined in the terminal, but clicking
one opened the preview overlay on "File not found": file-content/file-raw
resolve against the session workingDir and refuse anything outside it, and the
paths agents print most (a /tmp capture, Claude's own scratchpad, another
checkout) are outside it by definition. In the response viewer those paths were
not links at all.

- openFilePreview() detects an out-of-workspace path and registers it through
  POST /api/sessions/:id/attachments first, rendering by attachment id. That is
  the surface built for live external files, so the server-side guard is
  unchanged: secret trees blocked, symlinks resolved, extension allowlist. The
  workspace routes keep refusing escapes exactly as before.
- New optional `notify` field on that route. `notify: false` suppresses only the
  attachment:detected broadcast, so a click does not also pop a card announcing
  the file already filling the screen. Default stays true for the CLI and
  publish callers.
- _linkifyFilePaths() links paths in rendered response-viewer markdown. It walks
  text nodes and builds anchors with DOM APIs (the source is model output; never
  a string rebuild of sanitized markup), skips subtrees already inside an <a>,
  and keeps the message text byte-identical so copy-code is unaffected.
- One path pattern in constants.js now feeds both the xterm link provider and
  the chat linkifier, a fresh instance per call since lastIndex is per-object
  state. It picks up /Users and /mnt roots (nothing was clickable on macOS or
  WSL), plus docx/pptx and video/audio extensions.
- .file-preview-overlay moves to z-index 5100, above the response viewer at
  5000. At its old 2000 a path clicked in the chat opened the overlay behind the
  panel it was launched from.

Verified end to end on an isolated instance, desktop and phone viewport: real
clicks in the terminal and the chat both render the image, external md and pdf
render, /etc/hosts is still refused, workspace previews unchanged.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

test/link-provider-regex.test.ts

@@ -18,18 +18,25 @@ import { describe, it, expect } from 'vitest';
 import { readFileSync } from 'fs';
 import { join } from 'path';
 
-const SOURCE = readFileSync(join(__dirname, '..', 'src', 'web', 'public', 'terminal-ui.js'), 'utf-8');
+const publicFile = (name: string) => readFileSync(join(__dirname, '..', 'src', 'web', 'public', name), 'utf-8');
 
-/** Extract `const <name> = /.../g;` from the shipped source and build the RegExp. */
+const SOURCE = publicFile('terminal-ui.js');
+// The file-path pattern lives in constants.js: the response viewer linkifies the
+// same paths out of markdown, and one definition is what keeps a path that is
+// clickable in the terminal from being inert in the chat.
+const CONSTANTS_SOURCE = publicFile('constants.js');
+
+/** Extract `const <name> = /.../g;` from the shipped sources and build the RegExp. */
 function shippedPattern(name: string): RegExp {
-  const m = SOURCE.match(new RegExp(`const ${name} =\\s*\\n?\\s*(/(?:[^/\\\\\\n]|\\\\.)+/[a-z]*)`));
-  if (!m) throw new Error(`pattern ${name} not found in terminal-ui.js`);
+  const literal = new RegExp(`const ${name} =\\s*\\n?\\s*(/(?:[^/\\\\\\n]|\\\\.)+/[a-z]*)`);
+  const m = SOURCE.match(literal) ?? CONSTANTS_SOURCE.match(literal);
+  if (!m) throw new Error(`pattern ${name} not found in terminal-ui.js or constants.js`);
   const lit = m[1];
   const lastSlash = lit.lastIndexOf('/');
   return new RegExp(lit.slice(1, lastSlash), lit.slice(lastSlash + 1));
 }
 
-const PATTERN_NAMES = ['urlPattern', 'cmdPattern', 'extPattern', 'bashPattern'];
+const PATTERN_NAMES = ['urlPattern', 'cmdPattern', 'FILE_PATH_LINK_PATTERN', 'bashPattern'];
 
 /** Lines that made 0.9.10's cmdPattern backtrack exponentially (>2s each). */
 const KILLER_LINES = [
@@ -116,15 +123,24 @@ describe('terminal link-provider regexes (shipped source)', () => {
     }
   });
 
-  it('extPattern links pasted image/PDF attachment paths', () => {
+  it('the file-path pattern links pasted image/PDF/media attachment paths', () => {
     // `.claude-images/paste-*.png` is what Codeman writes for a pasted screenshot;
     // without image extensions the path rendered as plain, unclickable text.
-    const ext = shippedPattern('extPattern');
+    const ext = shippedPattern('FILE_PATH_LINK_PATTERN');
     const cases = [
       '/home/arkon/default/claudeman/.claude-images/paste-1785164958410-d11eb7d0.png',
       '/tmp/shot.jpeg',
       '/opt/app/report.pdf',
       '/home/a/diagram.svg',
+      // An agent's own scratchpad capture — the path shape this whole feature
+      // exists for, and the one that used to open a "File not found" preview.
+      '/tmp/claude-1000/-home-arkon-default-claudeman/7b3fefd2/scratchpad/probe-run-native.png',
+      // macOS and WSL roots: unmatched before, so Mac users had no clickable
+      // paths at all outside /var and /tmp.
+      '/Users/arbbot/codeman-cases/report.docx',
+      '/mnt/d/captures/demo.mp4',
+      // Longer extension of a family must win over its prefix (tsx over ts).
+      '/home/a/src/App.tsx',
     ];
     for (const path of cases) {
       ext.lastIndex = 0;
@@ -134,6 +150,13 @@ describe('terminal link-provider regexes (shipped source)', () => {
     }
   });
 
+  it('terminal-ui builds its path pattern from the shared factory', () => {
+    // Structural guard: a local literal here would drift from the response
+    // viewer's linkifier, which is the divergence the move exists to prevent.
+    expect(SOURCE).toContain('absoluteFilePathPattern()');
+    expect(SOURCE).not.toMatch(/const extPattern =\s*\n?\s*\//);
+  });
+
   it('cmdPattern arg group cannot match empty tokens (the exponential trigger)', () => {
     // structural guard: the dangerous construct is an empty-matchable token
     // inside a repeated group — `[^\s\/]*\s+` repeated. Check the pattern

test/response-viewer-file-links.test.ts

@@ -0,0 +1,137 @@
+/**
+ * @fileoverview Response-viewer file-path linkifier (`CodemanApp._linkifyFilePaths`).
+ *
+ * The viewer renders markdown, so a path an agent wrote — "wrote the chart to
+ * /tmp/.../chart.png" — arrived as inert text: the terminal's link provider
+ * never sees the chat, and the file it just produced was a copy-paste away
+ * instead of a click. The linkifier wraps those paths in an anchor the click
+ * delegate hands to the file-preview overlay.
+ *
+ * Two properties matter more than the linking itself and are pinned here:
+ *
+ *  1. **The text is untouched.** Anchors are built from TEXT NODES with DOM
+ *     APIs, never by rebuilding already-sanitized markup as a string, so the
+ *     message reads identically and "copy code" still yields exactly what the
+ *     agent printed.
+ *  2. **Model output cannot become markup.** The source is model text; a
+ *     path-shaped string carrying HTML must stay text.
+ *
+ * Loaded via `vm` with a jsdom document injected (same technique as
+ * connection-indicator.test.ts — no per-file jsdom environment, which would
+ * externalize node:fs under vite).
+ */
+import { readFileSync } from 'node:fs';
+import { performance } from 'node:perf_hooks';
+import { resolve } from 'node:path';
+import vm from 'node:vm';
+import { JSDOM } from 'jsdom';
+import { describe, expect, it, vi } from 'vitest';
+
+const dom = new JSDOM('<!DOCTYPE html><html><body></body></html>');
+const { document, NodeFilter } = dom.window;
+
+function loadCodemanAppClass() {
+  const constants = readFileSync(resolve(import.meta.dirname, '../src/web/public/constants.js'), 'utf8');
+  const source = readFileSync(resolve(import.meta.dirname, '../src/web/public/app.js'), 'utf8');
+  const context = vm.createContext({
+    console,
+    performance,
+    setInterval: vi.fn(),
+    clearInterval: vi.fn(),
+    setTimeout,
+    clearTimeout,
+    requestAnimationFrame: vi.fn(),
+    HTMLCanvasElement: class HTMLCanvasElement {},
+    fetch: vi.fn(),
+    document,
+    NodeFilter,
+    localStorage: { length: 0, key: vi.fn(), getItem: vi.fn(), setItem: vi.fn(), removeItem: vi.fn() },
+    window: { addEventListener: vi.fn(), removeEventListener: vi.fn() },
+    MobileDetection: {},
+  });
+  vm.runInContext(`${constants}\n${source}\nglobalThis.__CodemanApp = CodemanApp;`, context);
+  return (context as { __CodemanApp: { prototype: { _linkifyFilePaths(root: unknown): void } } }).__CodemanApp;
+}
+
+const CodemanApp = loadCodemanAppClass();
+const APP_SOURCE = readFileSync(resolve(import.meta.dirname, '../src/web/public/app.js'), 'utf8');
+
+/** Render `html` into a detached .rv-text div and run the linkifier over it. */
+function linkify(html: string): HTMLElement {
+  const app = Object.create(CodemanApp.prototype) as { _linkifyFilePaths(root: unknown): void };
+  const root = document.createElement('div');
+  root.className = 'rv-text';
+  root.innerHTML = html;
+  app._linkifyFilePaths(root);
+  return root as unknown as HTMLElement;
+}
+
+const paths = (root: HTMLElement) => Array.from(root.querySelectorAll('a.rv-path'));
+
+describe('response viewer file-path linkifier', () => {
+  it('links an absolute path written as prose', () => {
+    const path = '/tmp/claude-1000/-home-arkon-default-claudeman/7b3fefd2/scratchpad/probe-run-native.png';
+    const root = linkify(`<p>Saved the capture to ${path} — have a look.</p>`);
+
+    const links = paths(root);
+    expect(links).toHaveLength(1);
+    expect(links[0].getAttribute('data-path')).toBe(path);
+    expect(links[0].textContent).toBe(path);
+    expect(root.textContent).toBe(`Saved the capture to ${path} — have a look.`);
+  });
+
+  it('links a path inside inline code, which is how agents usually write one', () => {
+    const root = linkify('<p>See <code>/home/a/out/report.pdf</code> for the numbers.</p>');
+
+    const links = paths(root);
+    expect(links).toHaveLength(1);
+    expect(links[0].getAttribute('data-path')).toBe('/home/a/out/report.pdf');
+    // Still inside the <code> span — the code styling is not lost.
+    expect(links[0].closest('code')).not.toBeNull();
+  });
+
+  it('links every path in one text node and preserves the text between them', () => {
+    const root = linkify('<p>Compare /tmp/before.png with /tmp/after.png please</p>');
+
+    expect(paths(root).map((a) => a.getAttribute('data-path'))).toEqual(['/tmp/before.png', '/tmp/after.png']);
+    expect(root.textContent).toBe('Compare /tmp/before.png with /tmp/after.png please');
+  });
+
+  it('never re-cuts text already inside an anchor', () => {
+    // marked autolinks URLs; a path-looking tail inside one must stay whole, and
+    // a nested <a> is invalid markup that would swallow the outer link's click.
+    const root = linkify('<p><a href="https://example.com/x/y.png">https://example.com/x/y.png</a></p>');
+
+    expect(paths(root)).toHaveLength(0);
+    expect(root.querySelectorAll('a')).toHaveLength(1);
+    expect(root.querySelector('a')!.getAttribute('href')).toBe('https://example.com/x/y.png');
+  });
+
+  it('leaves text with no path untouched', () => {
+    const root = linkify('<p>Ratio 3/4 on 2026/08/16, see src/app.ts</p>');
+
+    expect(paths(root)).toHaveLength(0);
+    expect(root.textContent).toBe('Ratio 3/4 on 2026/08/16, see src/app.ts');
+  });
+
+  it('cannot turn model text into markup', () => {
+    // The anchor is built with createElement + textContent, so even a
+    // path-shaped payload stays text. (`<` also ends a match, so the linkifier
+    // never spans into it in the first place.)
+    const root = linkify('<p>/tmp/x.png&lt;img src=x onerror=alert(1)&gt;.png</p>');
+
+    expect(root.querySelector('img')).toBeNull();
+    expect(root.textContent).toContain('<img src=x onerror=alert(1)>.png');
+    for (const link of paths(root)) {
+      expect(link.innerHTML).toBe(link.textContent);
+    }
+  });
+
+  it('is wired into message rendering and the click delegate', () => {
+    // The linkifier is only reachable through these two call sites; losing
+    // either leaves inert paths (no linkify) or dead links (no handler).
+    expect(APP_SOURCE).toContain('this._linkifyFilePaths(renderedText)');
+    expect(APP_SOURCE).toMatch(/closest\('a\.rv-path'\)/);
+    expect(APP_SOURCE).toMatch(/openFilePreview\(filePath, this\.activeSessionId\)/);
+  });
+});

test/routes/file-routes-attachment-path-guard.test.ts

@@ -56,6 +56,7 @@ import {
   registerExternalAttachment,
   type AttachmentRecord,
 } from '../../src/attachment-registry.js';
+import { SseEvent } from '../../src/web/sse-events.js';
 
 const mockedStat = vi.mocked(fs.stat);
 const mockedRealpathSync = vi.mocked(realpathSync);
@@ -355,4 +356,51 @@ describe('file-routes attachment path guard (COD-53)', () => {
       attachmentRegistry.clearSession('test-session-mlc');
     });
   });
+
+  // ===== Quiet registration (click-to-preview) =====
+  // The file-preview overlay registers a clicked out-of-workspace path to mint
+  // an id it can render by. It is already putting the file on screen, so the
+  // usual attachment card + unread badge would announce what the user is
+  // looking at. `notify: false` suppresses ONLY the broadcast — the guard, the
+  // registry entry and the by-id routes are identical either way.
+  describe('quiet registration', () => {
+    const outside = '/tmp/claude-1000/scratchpad/probe-run-native.png';
+
+    it('broadcasts by default, so the CLI and publish paths keep their card', async () => {
+      mockedStat.mockResolvedValue({ size: 128, isFile: () => true, mtimeMs: 5 } as never);
+      const res = await harness.app.inject({
+        method: 'POST',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments`,
+        payload: { path: outside },
+      });
+
+      expect(res.statusCode).toBe(200);
+      expect(harness.ctx.broadcast).toHaveBeenCalledWith(SseEvent.AttachmentDetected, expect.anything());
+    });
+
+    it('registers and serves a clicked path without broadcasting when notify is false', async () => {
+      const content = Buffer.from('PNGDATA');
+      mockedStat.mockResolvedValue({ size: content.length, isFile: () => true, mtimeMs: 5 } as never);
+      mockedCreateReadStream.mockReturnValue(Readable.from([content]) as never);
+
+      const res = await harness.app.inject({
+        method: 'POST',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments`,
+        payload: { path: outside, notify: false },
+      });
+
+      expect(res.statusCode).toBe(200);
+      const body = JSON.parse(res.body);
+      expect(body.data.fileName).toBe('probe-run-native.png');
+      expect(harness.ctx.broadcast).not.toHaveBeenCalled();
+
+      // The preview renders from this route, so the id has to be live.
+      const rawRes = await harness.app.inject({
+        method: 'GET',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments/${body.data.attachmentId}/raw`,
+      });
+      expect(rawRes.statusCode).toBe(200);
+      expect(rawRes.headers['content-type']).toBe('image/png');
+    });
+  });
 });