fix(story-mode): a file a python or node script rewrites counts as changed

From review round 5: Claude rewrote textstats.py, the change the user
asked for, through `python3 - <<EOF ... open(p, "w").write(s)`, and
the page listed only the two files the same command wrote with `cat >`.
A script fed to python or node by a here-document is now read for the
files it opens for writing (`open(target, 'w'|'a'|...)`, `Path(...)
.write_text`, `writeFileSync`), with the target a string literal or a
name bound to one (`p = "textstats.py"`); anything computed is left
out, never guessed, and scratch targets are skipped. They are edits
without lines, like the files Claude Code says a command modified,
since what the script changed is not in the command.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/story-mode.ts

@@ -566,8 +566,9 @@ function judgeBashCommand(command: string): { intent: StoryIntent; segment: stri
  * Files a command writes through here-documents: `cat > f <<'EOF'`, `cat <<EOF > f`, `tee f <<EOF`
  * (and `>>` / `tee -a`, appends). Each becomes a whole-file edit of the body's lines. A relative
  * target resolves against the transcript line's `cwd` unless the command changed directory first;
- * scratch targets (`/tmp/x`, `"$S/x"`) are not project files. A body piped into a program
- * (`python3 - <<EOF`) writes nothing.
+ * scratch targets (`/tmp/x`, `"$S/x"`) are not project files. A script fed to python or node
+ * (`python3 - <<EOF`) is read for the files it opens for writing; those are edits without lines,
+ * since what the script changed is not in the command.
  */
 export function heredocWrites(command: string, cwd?: string): StoryEdit[] {
   const out: StoryEdit[] = [...echoWrites(command, cwd)];
@@ -600,6 +601,18 @@ export function heredocWrites(command: string, cwd?: string): StoryEdit[] {
         append = !!tee[1];
       }
     }
+    if (!target && /\b(python3?|node)\b/.test(before)) {
+      for (const written of scriptWrites(body)) {
+        if (SCRATCH_TARGET.test(written) || out.some((d) => d.file.endsWith(written))) continue;
+        const file =
+          written.startsWith('/') || !cwd || moved
+            ? written
+            : `${cwd.replace(/\/+$/, '')}/${written.replace(/^\.\//, '')}`;
+        out.push({ file, added: 0, removed: 0, created: false, hunks: [], truncated: true });
+        if (out.length >= 6) break;
+      }
+      continue;
+    }
     if (!target || SCRATCH_TARGET.test(target)) continue;
     const file =
       target.startsWith('/') || !cwd || moved ? target : `${cwd.replace(/\/+$/, '')}/${target.replace(/^\.\//, '')}`;
@@ -622,6 +635,41 @@ export function heredocWrites(command: string, cwd?: string): StoryEdit[] {
   return out;
 }
 
+/**
+ * Files a python or node script opens for writing: `open('a.py', 'w')`, `open(p, "w")` after
+ * `p = "a.py"`, `Path('a.py').write_text(...)`, `fs.writeFileSync('a.js', ...)`. Only string literals
+ * and names bound to one; anything computed is left out rather than guessed.
+ */
+function scriptWrites(body: string[]): string[] {
+  const names = new Map<string, string>();
+  for (const line of body) {
+    const m = /^\s*(?:(?:const|let|var)\s+)?([A-Za-z_]\w*)\s*=\s*(?:Path\(\s*)?(['"])([^'"\n]+)\2\s*\)?\s*;?\s*$/.exec(
+      line
+    );
+    if (m) names.set(m[1], m[3]);
+  }
+  const target = (lit: string | undefined, name: string | undefined) => lit ?? (name ? names.get(name) : undefined);
+  const found: Array<{ at: number; file: string }> = [];
+  const text = body.join('\n');
+  const patterns = [
+    // open(target, 'w') / open(target, mode="a+")
+    /\bopen\(\s*(?:(['"])([^'"\n]+)\1|([A-Za-z_]\w*))\s*,\s*(?:mode\s*=\s*)?(['"])([rwaxbt+]*)\4/g,
+    // Path(target).write_text( / name.write_text(
+    /(?:\bPath\(\s*(?:(['"])([^'"\n]+)\1|([A-Za-z_]\w*))\s*\)|\b([A-Za-z_]\w*))\.write_(?:text|bytes)\(/g,
+    // fs.writeFileSync(target / appendFileSync(target
+    /\b(?:write|append)File(?:Sync)?\(\s*(?:(['"])([^'"\n]+)\1|([A-Za-z_]\w*))/g,
+  ];
+  for (const [k, re] of patterns.entries()) {
+    for (const m of text.matchAll(re)) {
+      if (k === 0 && !/[wax+]/.test(m[5])) continue;
+      const file = k === 1 ? target(m[2], m[3] ?? m[4]) : target(m[2], m[3]);
+      if (file && !/[*?$`{}]/.test(file)) found.push({ at: m.index ?? 0, file });
+    }
+  }
+  // In the order the script writes them.
+  return unique(found.sort((x, y) => x.at - y.at).map((f) => f.file)).slice(0, 6);
+}
+
 /**
  * Whether a linter, formatter or type checker reported problems (`Found 3 errors.`, `1 file would be
  * reformatted`, `✖ 5 problems`, `error TS2322:`). Read when a trailing command (`; ls`) hid the exit code.

test/story-mode.test.ts

@@ -939,10 +939,42 @@ describe('buildStoryPage', () => {
       ),
       end(1000),
     ];
+    (lines[1] as { cwd?: string }).cwd = '/w';
     (lines[2] as { cwd?: string }).cwd = '/w';
     const page = pageOf(lines);
-    expect(page.events[1].edits?.map((d) => d.file)).toEqual(['/w/test_a.py']);
-    expect(page.filesChanged).toBe(1);
+    // The script's own write and the file Claude Code says changed: both, neither with lines.
+    expect(page.events[1].edits?.map((d) => [d.file, d.hunks.length])).toEqual([
+      ['/w/t.py', 0],
+      ['/w/test_a.py', 0],
+    ]);
+    expect(page.filesChanged).toBe(2);
+  });
+
+  it('a python or node script fed by a here-document: the files it opens for writing, never guessed', () => {
+    const files = (command: string) => heredocWrites(command, '/w').map((d) => d.file);
+    expect(
+      files(
+        [
+          "python3 - <<'EOF'",
+          'p = "textstats.py"',
+          's = open(p).read()',
+          "s = s.replace('a', 'b')",
+          'open(p, "w").write(s)',
+          "Path('README.md').write_text('# x')",
+          "with open('notes.txt', mode='a') as f: f.write('x')",
+          "open('/tmp/scratch.txt', 'w').write('x')",
+          "open(os.path.join(d, 'x.py'), 'w')",
+          "open('data.json').read()",
+          'EOF',
+        ].join('\n')
+      )
+    ).toEqual(['/w/textstats.py', '/w/README.md', '/w/notes.txt']);
+    expect(files("node <<'EOF'\nconst out = 'dist/app.js';\nfs.writeFileSync(out, code);\nEOF")).toEqual([
+      '/w/dist/app.js',
+    ]);
+    expect(files("python3 - <<'EOF'\nprint(open('a.py').read())\nEOF")).toEqual([]);
+    const [edit] = heredocWrites("python3 - <<'EOF'\nopen('a.py', 'w').write('x')\nEOF", '/w');
+    expect(edit).toMatchObject({ file: '/w/a.py', added: 0, removed: 0, hunks: [], truncated: true });
   });
 
   it('a compaction says what it did; ToolSearch is looking; EnterPlanMode says plan mode', () => {