fix: emit one separator style in --json path fields on Windows

AGENTS.md

@@ -18,7 +18,7 @@ Prefer `job`/`send` for agent work. Always ask the user before running any comma
 
 ZIP files are opened safely. URL downloads and ZIP extraction have a 2048 MB safety limit via `--max-download-mb`. Conflicting files use a numbered sibling such as `model-1.stl`.
 
-Agent-facing JSON path fields compact paths under the current home directory to `~`. Path-bearing JSON error messages use the same `~` compaction.
+Agent-facing JSON path fields compact paths under the current home directory to `~`, and always use `/` separators (on Windows too). Path-bearing JSON error messages use the same `~` compaction.
 
 ## Agent workflows and client architecture
 

CHANGELOG.md

@@ -7,6 +7,14 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
 
 ### Fixed
 
+- Windows `--json`: local path fields (`file`, `path`, `output`, `local_path`,
+  `workdir`, `config_path`, the `job` step paths, …) are emitted with `/`
+  separators instead of `\`. A single envelope previously mixed `\` in its
+  typed path fields with the `/` used by human-facing messages, remote printer
+  paths, and archive entries, so a consumer could not compare or join two path
+  fields without knowing which produced which. `~` home compaction is
+  unchanged. No effect on macOS/Linux.
+
 - User-facing docs now match shipped behaviour for `--confirm` on `job` /
   `send` (upload still runs; exit `0` `uploaded_not_printed`), the fail-closed
   camera streamer (opt-in, not auto-fallback), `doctor` fingerprint/`-v`

bambu_cli/paths.py

@@ -11,6 +11,7 @@
 __all__ = [
     "expand_path",
     "display_path",
+    "json_path",
     "path_for_message",
     "exception_for_message",
 ]
@@ -62,6 +63,25 @@ def display_path(path):
     return text
 
 
+def json_path(path):
+    """Return a local path with separators normalized to ``/`` for JSON output.
+
+    Agent-facing JSON path fields are emitted with forward slashes on every
+    platform, matching the convention ``path_for_message`` already uses for
+    human-facing text. Without this, a single Windows envelope mixes ``\\`` in
+    the typed path fields with the ``/`` that messages, remote printer paths,
+    and archive entries use — so a consumer cannot compare or join the two
+    without knowing which field came from where.
+
+    Home-directory compaction is NOT applied here; callers pass a value that
+    has already been through the JSON ``~`` compaction, which is a documented
+    privacy guarantee (see AGENTS.md). ``expand_path`` reverses it.
+    """
+    if path is None or os.sep == "/":
+        return path
+    return str(path).replace(os.sep, "/")
+
+
 def path_for_message(path):
     """Return a local path suitable for human and agent-facing messages."""
     display = display_path(path)

bambu_cli/utils.py

@@ -43,6 +43,7 @@ def _ensure_parent_dir(path):
     "downloaded_path",
     "extracted_path",
     "file",
+    "local_path",
     "output",
     "path",
     "printable_path",
@@ -70,6 +71,13 @@ def _redact_url_credentials(url):
 _HOME_DIR = os.path.expanduser("~")
 
 
+def _json_path(path):
+    """Normalize separators for JSON path fields. Delegates to ``paths.json_path``."""
+    from bambu_cli.paths import json_path
+
+    return json_path(path)
+
+
 def _display_path(path):
     if not path:
         return path
@@ -104,7 +112,8 @@ def _json_display_paths(value):
                 result[key] = _compact_all_strings(item)
             elif key in _JSON_PATH_KEYS and (isinstance(item, str) or item is None):
                 redacted = _redact_url_credentials(item)
-                result[key] = redacted if redacted != item else _display_path(item)
+                # A URL keeps its own separators; only local paths are normalized.
+                result[key] = redacted if redacted != item else _json_path(_display_path(item))
             else:
                 result[key] = _json_display_paths(item)
         return result

docs/api.md

@@ -53,6 +53,8 @@ Job failures may use the superset [`schemas/job_error.json`](schemas/job_error.j
 `next_command`, `recovery_hint`).
 
 Path fields under the current home directory are compacted to `~` in agent JSON.
+Local path fields always use `/` separators, on Windows too, so one envelope
+never mixes separator styles; expand `~` to get an openable path.
 
 ## Exit codes
 

tests/test_job.py

@@ -38,11 +38,18 @@ def emit(self, record):
 from bambu_cli import utils  # noqa: E402
 from bambu_cli.cli import build_parser  # noqa: E402
 from bambu_cli.paths import display_path as _display_path  # noqa: E402
+from bambu_cli.paths import json_path as _json_path  # noqa: E402
 from bambu_cli.constants import EXIT_COMMAND_ERROR, EXIT_FILE_ERROR  # noqa: E402
 from bambu_cli.context import RuntimeContext  # noqa: E402
 from bambu_cli.job import JobSteps, _run_job  # noqa: E402
 from bambu_cli.errors import BambuError
 
+
+def _json_path_field(path):
+    """The expected value of a JSON path field: ``~`` compaction, then ``/`` separators."""
+    return _json_path(_display_path(str(path)))
+
+
 def default_steps(**overrides):
     """``JobSteps`` wired to the real command handlers, with optional fakes.
 
@@ -460,7 +467,7 @@ def test_dry_run_local_printer_ready_file(tmp_path, capsys):
     assert payload["status"] == "dry_run_local_skipped"
     assert payload["would_upload"] is True
     assert payload["would_slice"] is False
-    assert payload["printable_path"] == _display_path(str(ready))
+    assert payload["printable_path"] == _json_path_field(ready)
 
 def test_dry_run_local_gcode_3mf_is_print_ready_not_sliced(tmp_path, capsys):
     """A local .gcode.3mf is print-ready: dry-run must report would_slice=False."""
@@ -598,7 +605,7 @@ def test_output_created_when_needed(tmp_path, capsys):
     _run_job(_ctx(), args, steps)
     assert out_dir.is_dir()
     payload = _read_json(capsys)
-    assert payload["workdir"] == _display_path(str(out_dir))
+    assert payload["workdir"] == _json_path_field(out_dir)
     assert payload["uploaded"] is True
 
 def test_output_ignored_for_printer_ready_local_file(tmp_path, capsys, caplog):
@@ -888,7 +895,7 @@ def _download(_a):
     _run_job(_ctx(), args, steps)
     payload = _read_json(capsys)
     assert payload["would_download"] is True
-    assert payload["downloaded_path"] == _display_path(str(downloaded))
+    assert payload["downloaded_path"] == _json_path_field(downloaded)
     assert payload["uploaded"] is True
     assert payload["remote_name"] == "model.3mf"
 
@@ -916,7 +923,7 @@ def _download(_a):
     payload = _read_json(capsys)
     assert payload["would_extract"] is True
     assert payload["archive_entry"] == "part.stl"
-    assert payload["extracted_path"] == _display_path(str(extracted))
+    assert payload["extracted_path"] == _json_path_field(extracted)
     assert payload["uploaded"] is True
 
 def test_url_invalid_max_download_mb_fails(capsys):

tests/test_jsonio.py

@@ -91,6 +91,63 @@ def test_display_path_requires_separator_boundary(monkeypatch):
     assert utils._display_path("/home/alice") == "~"
 
 
+# ---------------------------------------------------------------------------
+# paths.json_path / _json_display_paths — one separator style in JSON
+# ---------------------------------------------------------------------------
+
+
+def test_json_path_normalizes_windows_separators(monkeypatch):
+    """Local path fields emit "/" on Windows, matching path_for_message."""
+    import bambu_cli.paths as paths
+
+    monkeypatch.setattr(paths.os, "sep", "\\")
+    assert paths.json_path("~\\models\\cube.3mf") == "~/models/cube.3mf"
+    assert paths.json_path("D:\\out\\cube.3mf") == "D:/out/cube.3mf"
+    # Already-normalized input and None are pass-through.
+    assert paths.json_path("~/models/cube.3mf") == "~/models/cube.3mf"
+    assert paths.json_path(None) is None
+
+
+def test_json_envelope_uses_one_separator_style(monkeypatch):
+    """A Windows envelope must not mix "\\" path fields with "/" everywhere else."""
+    import bambu_cli.paths as paths
+    import bambu_cli.utils as utils
+
+    monkeypatch.setattr(paths.os, "sep", "\\")
+    monkeypatch.setattr(utils, "_HOME_DIR", "C:\\Users\\alice")
+    monkeypatch.setattr(utils.os, "sep", "\\")
+    monkeypatch.setattr(utils.os, "altsep", "/")
+
+    payload = utils._json_display_paths(
+        {
+            "file": "C:\\Users\\alice\\models\\cube.stl",
+            "path": "D:\\out\\cube_sliced.3mf",
+            "local_path": "C:\\Users\\alice\\w\\cube.3mf",
+            "remote_path": "/cube.3mf",
+            "filename": "cube_sliced.3mf",
+        }
+    )
+
+    assert payload["file"] == "~/models/cube.stl"
+    assert payload["path"] == "D:/out/cube_sliced.3mf"
+    # local_path is a declared local-path field, so it is normalized too.
+    assert payload["local_path"] == "~/w/cube.3mf"
+    # Remote printer paths are already "/" and must be left alone.
+    assert payload["remote_path"] == "/cube.3mf"
+    assert "\\" not in "".join(v for v in payload.values() if isinstance(v, str))
+
+
+def test_json_path_field_keeps_url_separators(monkeypatch):
+    """A URL in a path-keyed field keeps its own separators and stays redacted."""
+    import bambu_cli.paths as paths
+    import bambu_cli.utils as utils
+
+    monkeypatch.setattr(paths.os, "sep", "\\")
+    at = "@"
+    payload = utils._json_display_paths({"source": "https://user:pass" + at + "host.com/x.stl"})
+    assert payload["source"] == "https://host.com/x.stl"
+
+
 # ---------------------------------------------------------------------------
 # utils._resolve_ip — do not cache failures
 # ---------------------------------------------------------------------------

tests/test_slice_stub_integration.py

@@ -133,11 +133,13 @@ def test_success_emits_json_envelope(orca_env, capsys):
     payload = _last_json_object(capsys.readouterr().out)
     assert payload["status"] == "sliced"
     assert payload["command"] == "slice"
-    # emit_json compacts $HOME to ~ in every string value; on Windows CI the
-    # pytest tmpdir lives under the user profile, so expect the display form.
+    # emit_json compacts $HOME to ~ in every string value and normalizes local
+    # path separators to "/"; on Windows CI the pytest tmpdir lives under the
+    # user profile, so expect the compacted, forward-slashed form.
+    from bambu_cli.paths import json_path
     from bambu_cli.utils import _display_path
 
-    assert payload["path"] == _display_path(orca_env.outpath)
+    assert payload["path"] == json_path(_display_path(orca_env.outpath))
     assert payload["filename"] == "model_sliced.3mf"
     assert payload["bytes"] > 0
     assert payload["step_converted"] is False