fix(mcp): address final-review findings (sentinel exclusion, per-unit AMS data, generated_at, gating test, docs, cleanup)

README.md

@@ -63,6 +63,7 @@ It runs quietly in the background 24/7, capturing every print, filament change,
   - [Troubleshooting (Native)](#troubleshooting-native)
 - [Docker Setup](#docker-setup)
 - [Batch Importing Filament Colors and Filament Types](#batch-importing-filament-colors-and-filament-types)
+- [MCP Server (AI Agent Access)](#mcp-server-ai-agent-access)
 
 ---
 
@@ -296,3 +297,37 @@ Processing: PLA Basic.txt  →  type='PLA'  sub_type='PLA Basic'
 - **Created** — new color entries added to the database
 - **Skipped (duplicate)** — already existed, not changed
 - **Skipped (no type)** — only shown if `--no-auto-create-filament-type` is used and the filament type isn't in the database yet
+
+## MCP Server (AI Agent Access)
+
+Bambu-Run exposes printer status, print history, and filament inventory as
+read-only [MCP](https://modelcontextprotocol.io/) tools, so an AI agent (e.g.
+Claude Desktop, Claude Code) can query your printer directly.
+
+Install the extra:
+
+```bash
+pip install 'bambu-run[mcp]'
+```
+
+**stdio** (for a local agent on the same machine — e.g. Claude Desktop):
+
+```bash
+python manage.py bambu_mcp_server --transport stdio
+```
+
+**HTTP** (for a remote agent, or multiple callers over the network):
+
+```bash
+export BAMBU_RUN_MCP_API_KEY=your-secret-key
+python manage.py bambu_mcp_server --transport http --host 0.0.0.0 --port 8808
+```
+
+`BAMBU_RUN_MCP_API_KEY` is **required** for HTTP — the server refuses to start
+without it, since an unauthenticated network MCP endpoint would expose your
+printer and filament data to anyone who can reach the port. stdio needs no key
+(the OS process boundary is the trust boundary there).
+
+If serving behind a reverse proxy on a real domain, pass
+`--allowed-host your.domain.com` (repeatable) — otherwise the SDK's
+DNS-rebinding guard rejects requests with a real `Host` header.

bambu_run/conf.py

@@ -64,14 +64,6 @@ class _Settings:
     def MCP_PORT(self):
         return get_setting("BAMBU_RUN_MCP_PORT", 8808)
 
-    @property
-    def MCP_AUTH_BACKEND(self):
-        return get_setting("BAMBU_RUN_MCP_AUTH_BACKEND", None)
-
-    @property
-    def MCP_HIDE_SENSITIVE(self):
-        return get_setting("BAMBU_RUN_MCP_HIDE_SENSITIVE", False)
-
     # Cloud sync settings
     @property
     def CLOUD_SYNC_ENABLED(self):

bambu_run/mcp/filaments.py

@@ -1,6 +1,8 @@
 """list_filaments, get_filament -- the read_filament capability tools."""
 from __future__ import annotations
 
+from django.utils import timezone
+
 from bambu_run.mcp.shapes import normalize_consumed, remaining_status
 from bambu_run.models import Filament
 
@@ -44,7 +46,7 @@ def list_filaments(
         qs = qs.exclude(remaining_percent=-1).exclude(remaining_weight_grams__isnull=True).filter(remaining_weight_grams__gte=min_remaining_grams)
 
     spools = [_spool_summary(f, include_history) for f in qs.order_by("-remaining_percent")[:limit]]
-    return {"filaments": spools}
+    return {"generated_at": timezone.now().isoformat(), "filaments": spools}
 
 
 def _spool_summary(f, include_history):
@@ -110,6 +112,7 @@ def get_filament(filament_id: int) -> dict:
 
     return {
         **summary,
+        "generated_at": timezone.now().isoformat(),
         "purchase_date": f.purchase_date.isoformat() if f.purchase_date else None,
         "usage_history": usages,
     }

bambu_run/mcp/jobs.py

@@ -31,10 +31,11 @@ def list_print_jobs(
     returned by one call; narrow days or increase limit deliberately.
     """
     limit = min(limit, 100)
+    now = timezone.now()
     qs = PrintJob.objects.select_related("cloud_task", "device")
     if printer is not None:
         qs = qs.filter(device__in=resolve_printer(printer))
-    since = timezone.now() - timedelta(days=days)
+    since = now - timedelta(days=days)
     qs = qs.filter(start_time__gte=since)
     if status == "running":
         qs = qs.filter(final_status__isnull=True)
@@ -44,7 +45,7 @@ def list_print_jobs(
         qs = qs.filter(project_name__icontains=name_contains)
 
     jobs = list(qs.order_by("-start_time")[:limit])
-    return {"jobs": [_job_summary(j) for j in jobs]}
+    return {"generated_at": now.isoformat(), "jobs": [_job_summary(j) for j in jobs]}
 
 
 def _job_summary(job):
@@ -79,6 +80,7 @@ def get_print_job(job_id: int) -> dict:
     per-slot filament breakdown, estimate-vs-actual delta, and linked cloud
     metadata. Raises PrintJob.DoesNotExist if job_id is unknown.
     """
+    now = timezone.now()
     job = PrintJob.objects.select_related("cloud_task", "device").get(id=job_id)
     summary = _job_summary(job)
 
@@ -109,6 +111,7 @@ def get_print_job(job_id: int) -> dict:
     cloud = job.cloud_task
     return {
         **summary,
+        "generated_at": now.isoformat(),
         "estimate_delta_percent": delta_percent,
         "filament_usages": usages,
         "cloud_design_title": cloud.design_title if cloud else None,
@@ -125,7 +128,8 @@ def get_print_statistics(days: int = 30, printer: str | int | None = None) -> di
     most_used_material answers "what did I print most" directly for the
     requested window (days=7 for last week, days=30 for last month).
     """
-    since = timezone.now() - timedelta(days=days)
+    now = timezone.now()
+    since = now - timedelta(days=days)
     qs = PrintJob.objects.filter(start_time__gte=since)
     if printer is not None:
         qs = qs.filter(device__in=resolve_printer(printer))
@@ -142,7 +146,7 @@ def get_print_statistics(days: int = 30, printer: str | int | None = None) -> di
 
     cloud_qs = BambuCloudTask.objects.filter(print_jobs__in=qs).distinct()
     total_grams = cloud_qs.aggregate(s=Sum("weight_grams"))["s"]
-    jobs_without_cloud = total_jobs - cloud_qs.count()
+    jobs_without_cloud = qs.filter(cloud_task__isnull=True).count()
 
     # Same exclusion rules as normalize_consumed (starting_percent must be a
     # real reading, and consumption must be non-negative), expressed as a DB
@@ -150,6 +154,7 @@ def get_print_statistics(days: int = 30, printer: str | int | None = None) -> di
     valid_usage = (
         Q(starting_percent__gt=F("ending_percent"))
         & ~Q(starting_percent=-1)
+        & ~Q(ending_percent=-1)
         & Q(filament__initial_weight_grams__isnull=False)
     )
     material_rows = (
@@ -186,6 +191,7 @@ def get_print_statistics(days: int = 30, printer: str | int | None = None) -> di
     median_ratio = statistics.median(ratios) if ratios else None
 
     return {
+        "generated_at": now.isoformat(),
         "window_days": days,
         "total_jobs": total_jobs,
         "success_rate": success_rate,

bambu_run/mcp/status.py

@@ -89,9 +89,25 @@ def _temperatures(metric):
     }
 
 
+def _safe_tray_id(value, default=-1):
+    """Coerce a tray_id from the filaments JSON to int, defaulting on anything
+    that isn't a clean int (missing, None, or malformed) rather than crashing
+    the whole tool from one bad row."""
+    try:
+        return int(value)
+    except (TypeError, ValueError):
+        return default
+
+
 def _ams_units(printer, latest_metric):
     """Build ams_units from the latest metric's filaments, with remain_percent
-    smoothed against the printer's 5 most recent metric rows."""
+    smoothed against the printer's 5 most recent metric rows.
+
+    Per-unit humidity/temp come from PrinterMetrics.ams_units (a JSONField with
+    one entry per physical AMS unit) -- NOT from PrinterMetrics.ams_humidity_raw/
+    .ams_temp, which the collector only ever populates from unit 0's reading and
+    would otherwise stamp one unit's humidity onto every unit.
+    """
     recent_filament_lists = list(
         PrinterMetrics.objects.filter(device=printer)
         .order_by("-timestamp")
@@ -100,19 +116,24 @@ def _ams_units(printer, latest_metric):
     readings = defaultdict(list)
     for filaments in recent_filament_lists:
         for f in filaments or []:
-            key = (f.get("ams_unit_id"), int(f.get("tray_id", -1)))
+            key = (f.get("ams_unit_id"), _safe_tray_id(f.get("tray_id")))
             readings[key].append(f.get("remain_percent"))
 
+    unit_readings = {
+        u.get("unit_id"): u for u in (latest_metric.ams_units or [])
+    }
+
     units = {}
     for f in latest_metric.filaments or []:
         unit_id = f.get("ams_unit_id")
-        tray_id = int(f.get("tray_id", -1))
+        tray_id = _safe_tray_id(f.get("tray_id"))
         value, status = smoothed_remaining_percent(readings[(unit_id, tray_id)])
+        unit_reading = unit_readings.get(unit_id, {})
         unit = units.setdefault(unit_id, {
             "unit_id": unit_id,
             "type": f.get("ams_type", ""),
-            "humidity_raw": latest_metric.ams_humidity_raw,
-            "temp_c": float(latest_metric.ams_temp) if latest_metric.ams_temp is not None else None,
+            "humidity_raw": unit_reading.get("humidity_raw"),
+            "temp_c": float(unit_reading["temp"]) if unit_reading.get("temp") is not None else None,
             "slots": [],
         })
         color = f.get("color")
@@ -156,12 +177,13 @@ def get_metrics_history(
     """
     from bambu_run.views import sample_metrics  # reuse: same thinning the dashboard already uses
 
+    now = timezone.now()
     max_points = min(max_points, 500)
     target = resolve_printer(printer).first()
     if target is None:
-        return {"printer": None, "timestamps": [], "series": {}}
+        return {"generated_at": now.isoformat(), "printer": None, "timestamps": [], "series": {}}
 
-    since = timezone.now() - timedelta(hours=hours)
+    since = now - timedelta(hours=hours)
     rows = list(
         PrinterMetrics.objects.filter(device=target, timestamp__gte=since).order_by("timestamp")
     )
@@ -181,6 +203,7 @@ def get_metrics_history(
         series["cooling_fan_percent"] = [r.cooling_fan_speed for r in rows]
 
     return {
+        "generated_at": now.isoformat(),
         "printer": {"id": target.id, "name": target.name},
         "timestamps": [r.timestamp.isoformat() for r in rows],
         "series": series,

tests/test_mcp_filaments.py

@@ -15,6 +15,7 @@ def test_list_filaments_filters_material_sub_type_color():
 
     assert len(result["filaments"]) == 1
     assert result["filaments"][0]["sub_type"] == "PLA Matte"
+    assert "generated_at" in result
 
 
 @pytest.mark.django_db
@@ -117,6 +118,7 @@ def test_get_filament_returns_full_usage_history_with_data_quality():
     assert reliable["consumed_grams"] == 100
     assert unreliable["data_quality"] == "unreliable"
     assert unreliable["consumed_grams"] is None
+    assert "generated_at" in result
 
 
 @pytest.mark.django_db

tests/test_mcp_jobs.py

@@ -16,6 +16,7 @@ def test_list_print_jobs_orders_most_recent_first():
     result = list_print_jobs()
 
     assert [j["id"] for j in result["jobs"]] == [newer.id, older.id]
+    assert "generated_at" in result
 
 
 @pytest.mark.django_db
@@ -86,6 +87,7 @@ def test_get_print_job_marks_negative_consumption_unreliable():
     usage = result["filament_usages"][0]
     assert usage["consumed_grams"] is None
     assert usage["data_quality"] == "unreliable"
+    assert "generated_at" in result
 
 
 @pytest.mark.django_db
@@ -121,6 +123,21 @@ def test_get_print_statistics_success_rate_and_status_counts():
     assert result["success_rate"] == 0.5
     assert result["status_counts"]["FINISH"] == 1
     assert result["status_counts"]["FAILED"] == 1
+    assert "generated_at" in result
+
+
+@pytest.mark.django_db
+def test_get_print_statistics_excludes_ending_sentinel_from_material_mix():
+    p = Printer.objects.create(name="RNL-H2C", model="H2C", is_active=True)
+    job = PrintJob.objects.create(device=p, project_name="A", start_time=timezone.now(), final_status="FINISH")
+    pla = Filament.objects.create(type="PLA", brand="Bambu Lab", color="Black", initial_weight_grams=1000)
+    # ending_percent=-1 (no RFID read at job end) must not be counted as 610g of consumption
+    FilamentUsage.objects.create(print_job=job, filament=pla, tray_id=0, starting_percent=60, ending_percent=-1)
+
+    result = get_print_statistics(days=30)
+
+    assert result["material_mix_grams"] == {}
+    assert result["most_used_material"] is None
 
 
 @pytest.mark.django_db

tests/test_mcp_status.py

@@ -97,6 +97,44 @@ def test_get_printer_status_ams_slot_unread_sentinel():
     assert slot["remain_status"] == "unread"
 
 
+@pytest.mark.django_db
+def test_get_printer_status_ams_units_have_independent_humidity():
+    p = Printer.objects.create(name="RNL-H2C", model="H2C", is_active=True)
+    PrinterMetrics.objects.create(
+        device=p, timestamp=timezone.now(), gcode_state="RUNNING",
+        ams_humidity_raw=4,  # unit-0-only flat column, must NOT be used for unit 1
+        ams_units=[
+            {"unit_id": 0, "ams_type": "AMS 2 Pro", "humidity_raw": 4, "temp": 28.0},
+            {"unit_id": 1, "ams_type": "AMS", "humidity_raw": 7, "temp": 24.0},
+        ],
+        filaments=[
+            {"ams_unit_id": 0, "tray_id": "0", "type": "ABS", "remain_percent": 50},
+            {"ams_unit_id": 1, "tray_id": "0", "type": "PLA", "remain_percent": 60},
+        ],
+    )
+
+    result = get_printer_status(printer=p.id)
+
+    units_by_id = {u["unit_id"]: u for u in result["printers"][0]["ams_units"]}
+    assert units_by_id[0]["humidity_raw"] == 4
+    assert units_by_id[1]["humidity_raw"] == 7
+    assert units_by_id[0]["temp_c"] == 28.0
+    assert units_by_id[1]["temp_c"] == 24.0
+
+
+@pytest.mark.django_db
+def test_get_printer_status_tolerates_malformed_tray_id():
+    p = Printer.objects.create(name="RNL-H2C", model="H2C", is_active=True)
+    PrinterMetrics.objects.create(
+        device=p, timestamp=timezone.now(), gcode_state="RUNNING",
+        filaments=[{"ams_unit_id": 0, "tray_id": None, "type": "ABS", "remain_percent": 50}],
+    )
+
+    result = get_printer_status(printer=p.id)  # must not raise
+
+    assert result["printers"][0]["ams_units"][0]["slots"][0]["slot"] == -1
+
+
 @pytest.mark.django_db
 def test_get_printer_status_never_exposes_serial_or_ip():
     p = Printer.objects.create(
@@ -151,6 +189,7 @@ def test_get_metrics_history_returns_series_within_window():
     assert result["printer"]["id"] == p.id
     assert len(result["timestamps"]) == 3
     assert 999.0 not in result["series"]["nozzle_c"]
+    assert "generated_at" in result
 
 
 @pytest.mark.django_db
@@ -181,7 +220,10 @@ def test_get_metrics_history_hard_ceiling_500_points():
 @pytest.mark.django_db
 def test_get_metrics_history_no_matching_printer_returns_empty_shape():
     result = get_metrics_history(printer=None)
-    assert result == {"printer": None, "timestamps": [], "series": {}}
+    assert result["printer"] is None
+    assert result["timestamps"] == []
+    assert result["series"] == {}
+    assert "generated_at" in result
 
 
 from bambu_run.models import Hotend

tests/test_mcp_toolkit.py

@@ -56,6 +56,7 @@ async def test_read_printer_only_caller_cannot_see_or_call_filament_tool(db):
         visible = await client.list_tools()
         visible_names = {t.name for t in visible.tools}
         assert "list_filaments" not in visible_names
+        assert "list_print_jobs" not in visible_names
         assert "get_printer_status" in visible_names
 
         with pytest.raises(MCPError):