feat(visualize): open the graph in the browser by default

Auto-open after generating so plain `openkb visualize` just shows the
graph; pass --no-open for headless/CI use. The HTML is still written to
output/visualize/graph.html every run (latest snapshot, shareable). If a
browser can't be launched, print a hint instead of failing.

Author: KylinMountain

openkb/cli.py

@@ -1495,8 +1495,8 @@ def lint(ctx, fix):
 
 
 @cli.command()
-@click.option("--open", "open_browser", is_flag=True, default=False,
-              help="Open the generated graph in your browser.")
+@click.option("--open/--no-open", "open_browser", default=True,
+              help="Open the graph in your browser after generating (default: on; --no-open for headless).")
 @click.pass_context
 @_with_kb_lock(exclusive=False)
 def visualize(ctx, open_browser):
@@ -1516,7 +1516,12 @@ def visualize(ctx, open_browser):
     click.echo(f"Graph written to {out}  ({len(graph['nodes'])} nodes, {len(graph['edges'])} edges)")
     if open_browser:
         import webbrowser
-        webbrowser.open(out.resolve().as_uri())   # resolve() so a relative --kb-dir still yields a valid file URI
+        try:
+            opened = webbrowser.open(out.resolve().as_uri())   # resolve() so a relative --kb-dir still yields a valid file URI
+        except Exception:
+            opened = False
+        if not opened:
+            click.echo("(couldn't launch a browser — open the file above manually, or use --no-open)")
 
 
 def print_list(kb_dir: Path) -> None:

tests/test_visualize_cli.py

@@ -16,24 +16,38 @@ def _kb(tmp_path: Path) -> Path:
     return tmp_path
 
 
-def test_visualize_writes_html(tmp_path):
+def test_visualize_writes_html_and_opens_by_default(tmp_path):
     kb = _kb(tmp_path)
-    with patch("openkb.cli._find_kb_dir", return_value=kb):
+    with patch("openkb.cli._find_kb_dir", return_value=kb), \
+         patch("webbrowser.open") as wb:
         result = CliRunner().invoke(cli, ["visualize"])
     assert result.exit_code == 0, result.output
     out = kb / "output" / "visualize" / "graph.html"
     assert out.exists()
     html = out.read_text(encoding="utf-8")
     assert "<canvas" in html and '"concepts/a"' in html
+    wb.assert_called_once()   # auto-opens the browser by default
+
+
+def test_visualize_no_open_suppresses_browser(tmp_path):
+    kb = _kb(tmp_path)
+    with patch("openkb.cli._find_kb_dir", return_value=kb), \
+         patch("webbrowser.open") as wb:
+        result = CliRunner().invoke(cli, ["visualize", "--no-open"])
+    assert result.exit_code == 0, result.output
+    assert (kb / "output" / "visualize" / "graph.html").exists()
+    wb.assert_not_called()   # --no-open keeps it headless-friendly
 
 
 def test_visualize_empty_wiki(tmp_path):
     for sub in ("summaries", "concepts", "entities"):
         (tmp_path / "wiki" / sub).mkdir(parents=True)
     (tmp_path / ".openkb").mkdir()
     (tmp_path / ".openkb" / "config.yaml").write_text("model: gpt-4o-mini\n", encoding="utf-8")
-    with patch("openkb.cli._find_kb_dir", return_value=tmp_path):
+    with patch("openkb.cli._find_kb_dir", return_value=tmp_path), \
+         patch("webbrowser.open") as wb:
         result = CliRunner().invoke(cli, ["visualize"])
     assert result.exit_code == 0
     assert "No wiki pages" in result.output
     assert not (tmp_path / "output" / "visualize" / "graph.html").exists()
+    wb.assert_not_called()   # nothing to show → no browser