From 1e6bb04664a14cab99f483fd3c98095db147571d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastia=CC=81n=20Ortega?=
 <sebastian.ortegatorres@datadoghq.com>
Date: Wed, 24 Jun 2026 15:06:49 +0200
Subject: [PATCH 1/4] Emit Dag tags as metric tags

Add a [metrics] dag_tags_in_metrics option (default False). When enabled, each
Dag tag becomes a metric tag on Dag-run and task-instance metrics: tags with a
colon (e.g. env:prod) split into a key/value pair; plain tags (e.g. production)
become standalone DogStatsd tags, or tag=true in InfluxDB line protocol. Built-in
keys (dag_id, run_type, task_id, team_name) win on collision.

Tags come from the DagRun's dag_model.tags. The scheduler hot loop
(get_running_dag_runs_to_examine) and the executor-event failure path eager-load
them (gated on the flag) to avoid per-DagRun queries; other in-session emission
paths fall back to a lazy load, so the tags reach all Dag-run and task-instance
metrics. DagRun.dag_tags_for_stats swallows SQLAlchemyError so a detached/expired
instance degrades to no tags rather than breaking the caller.

TaskInstance.stats_tags reuses DagRun.dag_tags_for_stats and adds task_id and
run_type; the Task SDK worker reads the in-memory Dag and also adds run_type, so
ti.* metrics carry a consistent tag set across the worker and scheduler emitters.

The build_dag_metric_tags helper lives in the shared observability stats module.
---
 .../src/airflow/config_templates/config.yml   |  11 ++
 .../src/airflow/jobs/scheduler_job_runner.py  |   6 +
 airflow-core/src/airflow/models/dagrun.py     |  48 ++++++-
 .../src/airflow/models/taskinstance.py        |  14 +-
 .../tests/unit/jobs/test_scheduler_job.py     |  23 ++-
 airflow-core/tests/unit/models/test_dagrun.py | 133 ++++++++++++++----
 .../tests/unit/models/test_taskinstance.py    |  45 +++++-
 .../observability/metrics/datadog_logger.py   |  66 +++++----
 .../observability/metrics/stats.py            |  19 ++-
 .../observability/metrics/statsd_logger.py    |   5 +-
 .../tests/observability/metrics/test_stats.py |  50 +++++++
 .../airflow/sdk/execution_time/task_runner.py |  20 ++-
 .../execution_time/test_task_runner.py        |  79 +++++++++--
 13 files changed, 431 insertions(+), 88 deletions(-)

diff --git a/airflow-core/src/airflow/config_templates/config.yml b/airflow-core/src/airflow/config_templates/config.yml
index af11f9fe701d1..50c05084f3c96 100644
--- a/airflow-core/src/airflow/config_templates/config.yml
+++ b/airflow-core/src/airflow/config_templates/config.yml
@@ -1280,6 +1280,17 @@ metrics:
       type: boolean
       example: ~
       default: "False"
+    dag_tags_in_metrics:
+      description: |
+        Set to ``True`` to include Dag tags as metric tags on all Dag-run and task-instance metrics.
+        Tags that contain a colon (e.g. ``env:prod``) are split into a key/value pair. Plain tags
+        (e.g. ``production``) are emitted as standalone DogStatsd tags, or as ``tag=true`` in InfluxDB
+        line-protocol format. Disabled by default to avoid unexpected cardinality increases, since Dag
+        tags are free-form, user-defined strings.
+      version_added: 3.4.0
+      type: boolean
+      example: ~
+      default: "False"
     otel_on:
       description: |
         Enables sending metrics to OpenTelemetry.
diff --git a/airflow-core/src/airflow/jobs/scheduler_job_runner.py b/airflow-core/src/airflow/jobs/scheduler_job_runner.py
index f6d6a4787f629..96710b81cc4e2 100644
--- a/airflow-core/src/airflow/jobs/scheduler_job_runner.py
+++ b/airflow-core/src/airflow/jobs/scheduler_job_runner.py
@@ -1386,6 +1386,12 @@ def process_executor_events(
             .options(joinedload(TI.dag_run).selectinload(DagRun.created_dag_version))
             .options(joinedload(TI.dag_version))
         )
+        # When emitting Dag tags as metric tags, eager-load dag_model.tags so the per-finished-task
+        # ti_failures / operator_failures / task.*_duration metrics carry them without a per-TI lazy load.
+        if conf.getboolean("metrics", "dag_tags_in_metrics", fallback=False):
+            query = query.options(
+                joinedload(TI.dag_run).joinedload(DagRun.dag_model).selectinload(DagModel.tags)
+            )
         # row lock this entire set of taskinstances to make sure the scheduler doesn't fail when we have
         # multi-schedulers
         locked_query = with_row_locks(query, of=TI, session=session, skip_locked=True)
diff --git a/airflow-core/src/airflow/models/dagrun.py b/airflow-core/src/airflow/models/dagrun.py
index a51f16e51f603..b61dfdc425e40 100644
--- a/airflow-core/src/airflow/models/dagrun.py
+++ b/airflow-core/src/airflow/models/dagrun.py
@@ -53,16 +53,25 @@
     update,
 )
 from sqlalchemy.dialects import postgresql
-from sqlalchemy.exc import IntegrityError
+from sqlalchemy.exc import IntegrityError, SQLAlchemyError
 from sqlalchemy.ext.associationproxy import association_proxy
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.ext.mutable import MutableDict
-from sqlalchemy.orm import Mapped, declared_attr, joinedload, mapped_column, relationship, synonym, validates
+from sqlalchemy.orm import (
+    Mapped,
+    declared_attr,
+    joinedload,
+    mapped_column,
+    relationship,
+    synonym,
+    validates,
+)
 from sqlalchemy.orm.exc import StaleDataError
 from sqlalchemy.sql.expression import false, select
 from sqlalchemy.sql.functions import coalesce
 
 from airflow._shared.observability.metrics import stats
+from airflow._shared.observability.metrics.stats import build_dag_metric_tags
 from airflow._shared.observability.traces import (
     DAGRUN_PARENT_TRACE_CONTEXT_KEY,
     TASK_SPAN_DETAIL_LEVEL_KEY,
@@ -576,11 +585,36 @@ def check_version_id_exists_in_dr(self, dag_version_id: UUID, *, session: Sessio
         )
         return session.scalar(select_stmt)
 
+    def dag_tags_for_stats(self) -> dict[str, str]:
+        """Convert dag tags to metric tags. Tags with ':' become key:value; others are standalone (empty value)."""
+        if not airflow_conf.getboolean("metrics", "dag_tags_in_metrics", fallback=False):
+            return {}
+        try:
+            # Lazy-loads dag_model.tags if not already loaded. The scheduler hot loop
+            # (get_running_dag_runs_to_examine) eager-loads these to avoid a per-DagRun query; other,
+            # low-frequency emission paths fall back to this lazy load. On a detached/expired DagRun
+            # the load raises — swallow it so metric tagging never breaks the caller.
+            if not self.dag_model or not self.dag_model.tags:
+                return {}
+            return build_dag_metric_tags(tag.name for tag in self.dag_model.tags)
+        except SQLAlchemyError:
+            return {}
+
     @property
     def stats_tags(self) -> dict[str, str]:
-        return prune_dict(
-            {"dag_id": self.dag_id, "run_type": self.run_type, "team_name": getattr(self, "_team_name", None)}
+        # prune_dict strips falsy values, so merge dag tags after it runs so standalone
+        # tags (empty value) are preserved for DogStatsD emission.
+        base = prune_dict(
+            {
+                "dag_id": self.dag_id,
+                # bare value so it serializes as e.g. "scheduled", not "dagruntype.scheduled"
+                "run_type": getattr(self.run_type, "value", self.run_type),
+                "team_name": getattr(self, "_team_name", None),
+            }
         )
+        dag_tags = self.dag_tags_for_stats()
+        # Built-in keys win on collision; dag tags fill in everything else.
+        return {**dag_tags, **base}
 
     def get_state(self):
         return self._state
@@ -733,6 +767,12 @@ def get_running_dag_runs_to_examine(cls, session: Session) -> ScalarResult[DagRu
             .limit(cls.DEFAULT_DAGRUNS_TO_EXAMINE)
         )
 
+        # When dag tags are emitted as metric tags, eagerly load dag_model.tags so stats_tags
+        # does not fire a per-DagRun N+1 lazy load in the scheduler loop. Off by default, so the
+        # extra load is only paid when the feature is enabled.
+        if airflow_conf.getboolean("metrics", "dag_tags_in_metrics", fallback=False):
+            query = query.options(joinedload(cls.dag_model).selectinload(DagModel.tags))
+
         query = query.where(DagRun.run_after <= func.now())
 
         result = session.scalars(with_row_locks(query, of=cls, session=session, skip_locked=True)).unique()
diff --git a/airflow-core/src/airflow/models/taskinstance.py b/airflow-core/src/airflow/models/taskinstance.py
index 1c7de2185e607..6a277e2710d2b 100644
--- a/airflow-core/src/airflow/models/taskinstance.py
+++ b/airflow-core/src/airflow/models/taskinstance.py
@@ -757,9 +757,19 @@ def __hash__(self):
     @property
     def stats_tags(self) -> dict[str, str]:
         """Returns task instance tags."""
-        return prune_dict(
-            {"dag_id": self.dag_id, "task_id": self.task_id, "team_name": getattr(self, "_team_name", None)}
+        run_type = self.dag_run.run_type
+        base = prune_dict(
+            {
+                "dag_id": self.dag_id,
+                "task_id": self.task_id,
+                # bare value so it serializes as e.g. "scheduled", not "dagruntype.scheduled"
+                "run_type": getattr(run_type, "value", run_type),
+                "team_name": getattr(self, "_team_name", None),
+            }
         )
+        dag_tags = self.dag_run.dag_tags_for_stats()
+        # Built-in keys win on collision; dag tags fill in everything else.
+        return {**dag_tags, **base}
 
     @staticmethod
     def insert_mapping(
diff --git a/airflow-core/tests/unit/jobs/test_scheduler_job.py b/airflow-core/tests/unit/jobs/test_scheduler_job.py
index 1f3b6992c3e1c..2e89843c7fa62 100644
--- a/airflow-core/tests/unit/jobs/test_scheduler_job.py
+++ b/airflow-core/tests/unit/jobs/test_scheduler_job.py
@@ -518,8 +518,13 @@ def test_process_executor_events(self, mock_get_backend, mock_task_callback, dag
                     "scheduler.tasks.killed_externally",
                     tags={"dag_id": dag_id, "task_id": ti1.task_id},
                 ),
-                mock.call("operator_failures_EmptyOperator", tags={"dag_id": dag_id, "task_id": ti1.task_id}),
-                mock.call("ti_failures", tags={"dag_id": dag_id, "task_id": ti1.task_id}),
+                mock.call(
+                    "operator_failures_EmptyOperator",
+                    tags={"dag_id": dag_id, "task_id": ti1.task_id, "run_type": "manual"},
+                ),
+                mock.call(
+                    "ti_failures", tags={"dag_id": dag_id, "task_id": ti1.task_id, "run_type": "manual"}
+                ),
             ],
             any_order=True,
         )
@@ -645,8 +650,11 @@ def test_process_executor_events_with_no_callback(self, mock_get_backend, mock_t
                     "scheduler.tasks.killed_externally",
                     tags={"dag_id": dag_id, "task_id": task_id},
                 ),
-                mock.call("operator_failures_EmptyOperator", tags={"dag_id": dag_id, "task_id": task_id}),
-                mock.call("ti_failures", tags={"dag_id": dag_id, "task_id": task_id}),
+                mock.call(
+                    "operator_failures_EmptyOperator",
+                    tags={"dag_id": dag_id, "task_id": task_id, "run_type": "manual"},
+                ),
+                mock.call("ti_failures", tags={"dag_id": dag_id, "task_id": task_id, "run_type": "manual"}),
             ],
             any_order=True,
         )
@@ -9825,7 +9833,12 @@ def test_multi_team_sets_team_name_on_task_instances(self, dag_maker, mock_execu
             ti._team_name = team_name
 
         assert ti._team_name == "team_a"
-        assert ti.stats_tags == {"dag_id": "dag_a", "task_id": "task_a", "team_name": "team_a"}
+        assert ti.stats_tags == {
+            "dag_id": "dag_a",
+            "task_id": "task_a",
+            "team_name": "team_a",
+            "run_type": dr.run_type,
+        }
 
     @conf_vars({("core", "multi_team"): "true"})
     def test_do_scheduling_multi_team_schedules_task_instances(self, dag_maker, session):
diff --git a/airflow-core/tests/unit/models/test_dagrun.py b/airflow-core/tests/unit/models/test_dagrun.py
index 64b4947ec4c6f..5e0d517de625c 100644
--- a/airflow-core/tests/unit/models/test_dagrun.py
+++ b/airflow-core/tests/unit/models/test_dagrun.py
@@ -4563,34 +4563,113 @@ def test_context_carrier_parent_conf(self, dag_maker, conf, embeds):
             assert trace_id != _EXTERNAL_TRACE_ID
 
 
-class TestDagRunStatsTagsTeamName:
-    def test_stats_tags_without_team_name(self, dag_maker):
-        """stats_tags should not include team_name when _team_name is not set."""
-        with dag_maker("test_dag"):
-            EmptyOperator(task_id="t1")
-        dr = dag_maker.create_dagrun()
-        tags = dr.stats_tags
-        assert "team_name" not in tags
-        assert tags == {"dag_id": "test_dag", "run_type": "manual"}
+def test_stats_tags_without_team_name(dag_maker):
+    """stats_tags omits team_name when _team_name is not set."""
+    with dag_maker("test_dag"):
+        EmptyOperator(task_id="t1")
+    dr = dag_maker.create_dagrun()
+    assert dr.stats_tags == {"dag_id": "test_dag", "run_type": dr.run_type}
 
-    def test_stats_tags_with_team_name(self, dag_maker):
-        """stats_tags should include team_name when _team_name is set."""
-        with dag_maker("test_dag"):
-            EmptyOperator(task_id="t1")
-        dr = dag_maker.create_dagrun()
-        dr._team_name = "my_team"
-        tags = dr.stats_tags
-        assert tags["team_name"] == "my_team"
-        assert tags == {"dag_id": "test_dag", "run_type": "manual", "team_name": "my_team"}
-
-    def test_stats_tags_with_none_team_name(self, dag_maker):
-        """stats_tags should not include team_name when _team_name is None."""
-        with dag_maker("test_dag"):
-            EmptyOperator(task_id="t1")
-        dr = dag_maker.create_dagrun()
-        dr._team_name = None
-        tags = dr.stats_tags
-        assert "team_name" not in tags
+
+def test_stats_tags_with_team_name(dag_maker):
+    """stats_tags includes team_name when _team_name is set."""
+    with dag_maker("test_dag"):
+        EmptyOperator(task_id="t1")
+    dr = dag_maker.create_dagrun()
+    dr._team_name = "my_team"
+    assert dr.stats_tags == {"dag_id": "test_dag", "run_type": dr.run_type, "team_name": "my_team"}
+
+
+def test_stats_tags_with_none_team_name(dag_maker):
+    """stats_tags omits team_name when _team_name is None."""
+    with dag_maker("test_dag"):
+        EmptyOperator(task_id="t1")
+    dr = dag_maker.create_dagrun()
+    dr._team_name = None
+    assert dr.stats_tags == {"dag_id": "test_dag", "run_type": dr.run_type}
+
+
+def test_stats_tags_dag_tags_disabled_by_default(dag_maker, session):
+    """With the flag off (the default), dag tags must not leak into metrics."""
+    with dag_maker("disabled_tag_dag", tags=["production", "env:prod"], session=session):
+        pass
+    dr = dag_maker.create_dagrun()
+    _ = dr.dag_model.tags
+    assert dr.stats_tags == {"dag_id": "disabled_tag_dag", "run_type": dr.run_type}
+
+
+@conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+def test_stats_tags_without_dag_tags(dag_maker, session):
+    with dag_maker("no_tags_dag", session=session):
+        pass
+    dr = dag_maker.create_dagrun()
+    _ = dr.dag_model.tags
+    assert dr.stats_tags == {"dag_id": "no_tags_dag", "run_type": dr.run_type}
+
+
+@conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+def test_stats_tags_with_standalone_dag_tag(dag_maker, session):
+    with dag_maker("standalone_tag_dag", tags=["production"], session=session):
+        pass
+    dr = dag_maker.create_dagrun()
+    _ = dr.dag_model.tags  # eager-load so _dag_tags_for_stats sees the tags
+    tags = dr.stats_tags
+    assert tags == {"dag_id": "standalone_tag_dag", "run_type": "manual", "production": ""}
+    # run_type is the bare value, not a DagRunType enum (serializes as "manual", not "dagruntype.manual")
+    assert type(tags["run_type"]) is str
+
+
+@conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+def test_stats_tags_with_key_value_dag_tag(dag_maker, session):
+    with dag_maker("kv_tag_dag", tags=["env:staging"], session=session):
+        pass
+    dr = dag_maker.create_dagrun()
+    _ = dr.dag_model.tags
+    assert dr.stats_tags == {"dag_id": "kv_tag_dag", "run_type": dr.run_type, "env": "staging"}
+
+
+@conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+def test_stats_tags_builtin_keys_win_on_collision(dag_maker, session):
+    with dag_maker("collision_dag", tags=["dag_id:sneaky"], session=session):
+        pass
+    dr = dag_maker.create_dagrun()
+    _ = dr.dag_model.tags
+    # built-in dag_id wins over the colliding "dag_id:sneaky" tag
+    assert dr.stats_tags == {"dag_id": "collision_dag", "run_type": dr.run_type}
+
+
+@conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+def test_stats_tags_lazy_loads_dag_tags_when_not_eager_loaded(dag_maker, session):
+    """When dag_model is not eager-loaded, stats_tags lazy-loads it in-session so tags still appear."""
+    from sqlalchemy import inspect as sa_inspect
+
+    with dag_maker("lazy_tag_dag", tags=["env:prod"], session=session):
+        pass
+    dr = dag_maker.create_dagrun()
+    session.expire(dr, ["dag_model"])  # not eager-loaded
+    assert "dag_model" in sa_inspect(dr).unloaded
+
+    # lazy fallback loads dag_model.tags in-session, so the tags are still emitted
+    assert dr.stats_tags == {"dag_id": "lazy_tag_dag", "run_type": dr.run_type, "env": "prod"}
+
+
+@conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+def test_get_running_dag_runs_to_examine_eager_loads_dag_tags(dag_maker, session):
+    """With the flag on, the scheduler query eager-loads dag_model.tags so stats_tags fires no lazy load."""
+    from sqlalchemy import inspect as sa_inspect
+
+    with dag_maker("eager_tag_dag", tags=["env:prod"], session=session):
+        pass
+    dag_maker.create_dagrun(state=DagRunState.RUNNING)
+    session.commit()
+
+    dr = next(
+        r for r in DagRun.get_running_dag_runs_to_examine(session=session) if r.dag_id == "eager_tag_dag"
+    )
+    # dag_model and its tags are already populated — no lazy load needed at metric-emission time.
+    assert "dag_model" not in sa_inspect(dr).unloaded
+    assert "tags" not in sa_inspect(dr.dag_model).unloaded
+    assert dr.stats_tags == {"dag_id": "eager_tag_dag", "run_type": dr.run_type, "env": "prod"}
 
 
 class TestClearPartitionRuns:
diff --git a/airflow-core/tests/unit/models/test_taskinstance.py b/airflow-core/tests/unit/models/test_taskinstance.py
index 7f1a193d96380..029764e9a942d 100644
--- a/airflow-core/tests/unit/models/test_taskinstance.py
+++ b/airflow-core/tests/unit/models/test_taskinstance.py
@@ -2431,7 +2431,7 @@ def test_handle_failure_no_task(self, mock_get_backend, dag_maker):
         ti.task = None
         ti.state = State.QUEUED
         session.flush()
-        expected_stats_tags = {"dag_id": ti.dag_id, "task_id": ti.task_id}
+        expected_stats_tags = {"dag_id": ti.dag_id, "task_id": ti.task_id, "run_type": dr.run_type}
 
         assert ti.task is None, "Check critical pre-condition"
 
@@ -4381,7 +4381,7 @@ def test_stats_tags_without_team_name(self, dag_maker, session):
         ti = dr.get_task_instance("my_task", session=session)
         tags = ti.stats_tags
         assert "team_name" not in tags
-        assert tags == {"dag_id": "test_dag", "task_id": "my_task"}
+        assert tags == {"dag_id": "test_dag", "task_id": "my_task", "run_type": dr.run_type}
 
     def test_stats_tags_with_team_name(self, dag_maker, session):
         """stats_tags should include team_name when _team_name is set."""
@@ -4392,7 +4392,12 @@ def test_stats_tags_with_team_name(self, dag_maker, session):
         ti._team_name = "my_team"
         tags = ti.stats_tags
         assert tags["team_name"] == "my_team"
-        assert tags == {"dag_id": "test_dag", "task_id": "my_task", "team_name": "my_team"}
+        assert tags == {
+            "dag_id": "test_dag",
+            "task_id": "my_task",
+            "team_name": "my_team",
+            "run_type": dr.run_type,
+        }
 
     def test_stats_tags_with_none_team_name(self, dag_maker, session):
         """stats_tags should not include team_name when _team_name is None."""
@@ -4404,17 +4409,47 @@ def test_stats_tags_with_none_team_name(self, dag_maker, session):
         tags = ti.stats_tags
         assert "team_name" not in tags
 
+    @conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+    def test_stats_tags_match_worker_tag_set(self, dag_maker, session):
+        """ti_failures (and other ti.* metrics) are emitted from both the worker
+        (RuntimeTaskInstance.stats_tags) and the scheduler (TaskInstance.stats_tags); both must produce
+        the same tag set. The worker side is asserted in test_task_runner.py
+        (test_stats_tags_with_standalone_and_key_value_tags); this guards the scheduler side against drift:
+        dag tags + dag_id + task_id + run_type.
+        """
+        with dag_maker("parity_dag", tags=["env:prod", "production"], session=session):
+            EmptyOperator(task_id="t1")
+        dr = dag_maker.create_dagrun()
+        ti = dr.get_task_instance("t1", session=session)
+        tags = ti.stats_tags
+        assert tags == {
+            "dag_id": "parity_dag",
+            "task_id": "t1",
+            "run_type": "manual",
+            "env": "prod",
+            "production": "",
+        }
+        # run_type must be the bare value (not a DagRunType enum) so it serializes identically to
+        # the worker side, e.g. "manual" not "dagruntype.manual".
+        assert type(tags["run_type"]) is str
+
     @pytest.mark.parametrize(
         ("team_name", "expected_tags"),
         [
             pytest.param(
                 "my_team",
-                {"dag_id": "test_dag", "task_id": "my_task", "team_name": "my_team", "queue": "default"},
+                {
+                    "dag_id": "test_dag",
+                    "task_id": "my_task",
+                    "team_name": "my_team",
+                    "queue": "default",
+                    "run_type": "manual",
+                },
                 id="with_team",
             ),
             pytest.param(
                 None,
-                {"dag_id": "test_dag", "task_id": "my_task", "queue": "default"},
+                {"dag_id": "test_dag", "task_id": "my_task", "queue": "default", "run_type": "manual"},
                 id="without_team",
             ),
         ],
diff --git a/shared/observability/src/airflow_shared/observability/metrics/datadog_logger.py b/shared/observability/src/airflow_shared/observability/metrics/datadog_logger.py
index 129354c3a4381..4a22c9b6c3666 100644
--- a/shared/observability/src/airflow_shared/observability/metrics/datadog_logger.py
+++ b/shared/observability/src/airflow_shared/observability/metrics/datadog_logger.py
@@ -58,6 +58,17 @@ def __init__(
         self.stat_name_handler = stat_name_handler
         self.statsd_influxdb_enabled = statsd_influxdb_enabled
 
+    @staticmethod
+    def _build_tags_list(
+        tags: dict[str, str],
+        metric_tags_validator: Any,
+    ) -> list[str]:
+        return [
+            (f"{key}:{value}" if value != "" else key)
+            for key, value in tags.items()
+            if metric_tags_validator.test(key)
+        ]
+
     @validate_stat
     def incr(
         self,
@@ -68,12 +79,11 @@ def incr(
         tags: dict[str, str] | None = None,
     ) -> None:
         """Increment stat."""
-        if self.metrics_tags and isinstance(tags, dict):
-            tags_list = [
-                f"{key}:{value}" for key, value in tags.items() if self.metric_tags_validator.test(key)
-            ]
-        else:
-            tags_list = []
+        tags_list = (
+            self._build_tags_list(tags, self.metric_tags_validator)
+            if self.metrics_tags and isinstance(tags, dict)
+            else []
+        )
         if self.metrics_validator.test(stat):
             return self.dogstatsd.increment(metric=stat, value=count, tags=tags_list, sample_rate=rate)
         return None
@@ -88,12 +98,11 @@ def decr(
         tags: dict[str, str] | None = None,
     ) -> None:
         """Decrement stat."""
-        if self.metrics_tags and isinstance(tags, dict):
-            tags_list = [
-                f"{key}:{value}" for key, value in tags.items() if self.metric_tags_validator.test(key)
-            ]
-        else:
-            tags_list = []
+        tags_list = (
+            self._build_tags_list(tags, self.metric_tags_validator)
+            if self.metrics_tags and isinstance(tags, dict)
+            else []
+        )
         if self.metrics_validator.test(stat):
             return self.dogstatsd.decrement(metric=stat, value=count, tags=tags_list, sample_rate=rate)
         return None
@@ -109,12 +118,11 @@ def gauge(
         tags: dict[str, str] | None = None,
     ) -> None:
         """Gauge stat."""
-        if self.metrics_tags and isinstance(tags, dict):
-            tags_list = [
-                f"{key}:{value}" for key, value in tags.items() if self.metric_tags_validator.test(key)
-            ]
-        else:
-            tags_list = []
+        tags_list = (
+            self._build_tags_list(tags, self.metric_tags_validator)
+            if self.metrics_tags and isinstance(tags, dict)
+            else []
+        )
         if self.metrics_validator.test(stat):
             return self.dogstatsd.gauge(metric=stat, value=value, tags=tags_list, sample_rate=rate)
         return None
@@ -128,12 +136,11 @@ def timing(
         tags: dict[str, str] | None = None,
     ) -> None:
         """Stats timing."""
-        if self.metrics_tags and isinstance(tags, dict):
-            tags_list = [
-                f"{key}:{value}" for key, value in tags.items() if self.metric_tags_validator.test(key)
-            ]
-        else:
-            tags_list = []
+        tags_list = (
+            self._build_tags_list(tags, self.metric_tags_validator)
+            if self.metrics_tags and isinstance(tags, dict)
+            else []
+        )
         if self.metrics_validator.test(stat):
             if isinstance(dt, datetime.timedelta):
                 dt = dt.total_seconds() * 1000.0
@@ -148,12 +155,11 @@ def timer(
         **kwargs,
     ) -> Timer:
         """Timer metric that can be cancelled."""
-        if self.metrics_tags and isinstance(tags, dict):
-            tags_list = [
-                f"{key}:{value}" for key, value in tags.items() if self.metric_tags_validator.test(key)
-            ]
-        else:
-            tags_list = []
+        tags_list = (
+            self._build_tags_list(tags, self.metric_tags_validator)
+            if self.metrics_tags and isinstance(tags, dict)
+            else []
+        )
         if stat and self.metrics_validator.test(stat):
             return Timer(self.dogstatsd.timed(stat, tags=tags_list, **kwargs))
         return Timer()
diff --git a/shared/observability/src/airflow_shared/observability/metrics/stats.py b/shared/observability/src/airflow_shared/observability/metrics/stats.py
index 5140314922a67..7b51e580cd036 100644
--- a/shared/observability/src/airflow_shared/observability/metrics/stats.py
+++ b/shared/observability/src/airflow_shared/observability/metrics/stats.py
@@ -20,7 +20,7 @@
 import os
 import re
 import socket
-from collections.abc import Callable
+from collections.abc import Callable, Iterable
 from typing import TYPE_CHECKING, Any
 
 from .base_stats_logger import NoStatsLogger
@@ -35,6 +35,23 @@
 _VALID_STAT_NAME_CHARS_RE = re.compile(r"^[a-zA-Z0-9_.-]+$")
 _INVALID_STAT_NAME_CHARS_RE = re.compile(r"[^a-zA-Z0-9_.-]")
 
+
+def build_dag_metric_tags(tag_names: Iterable[str]) -> dict[str, str]:
+    """
+    Convert Dag tag strings into metric tags.
+
+    Tags with a non-empty value after a ``:`` (e.g. ``env:prod``) split into a
+    ``key: value`` pair. Plain tags (e.g. ``production``) and tags with no value
+    after the colon (e.g. ``env:``) map to an empty string, emitted as a standalone
+    DogStatsd tag or as ``tag=true`` in InfluxDB line protocol.
+    """
+    result: dict[str, str] = {}
+    for name in tag_names:
+        key, _, value = name.partition(":")
+        result[key] = value
+    return result
+
+
 # Module-level singleton state.
 _factory: Callable[[], StatsLogger | NoStatsLogger] | None = None
 _backend: StatsLogger | NoStatsLogger | None = None
diff --git a/shared/observability/src/airflow_shared/observability/metrics/statsd_logger.py b/shared/observability/src/airflow_shared/observability/metrics/statsd_logger.py
index 3500a04dc7be3..547f680db50f0 100644
--- a/shared/observability/src/airflow_shared/observability/metrics/statsd_logger.py
+++ b/shared/observability/src/airflow_shared/observability/metrics/statsd_logger.py
@@ -52,8 +52,9 @@ def wrapper(
             if stat is not None and tags is not None:
                 for k, v in tags.items():
                     if self.metric_tags_validator.test(k):
-                        if all(c not in [",", "="] for c in f"{v}{k}"):
-                            stat += f",{k}={v}"
+                        v_str = "true" if v == "" else v
+                        if all(c not in [",", "="] for c in f"{v_str}{k}"):
+                            stat += f",{k}={v_str}"
                         else:
                             log.error("Dropping invalid tag: %s=%s.", k, v)
         return fn(self, stat, *args, tags=tags, **kwargs)
diff --git a/shared/observability/tests/observability/metrics/test_stats.py b/shared/observability/tests/observability/metrics/test_stats.py
index 4121ffe9eee85..ffef79108dc1a 100644
--- a/shared/observability/tests/observability/metrics/test_stats.py
+++ b/shared/observability/tests/observability/metrics/test_stats.py
@@ -34,6 +34,7 @@
 from airflow_shared.observability.metrics import datadog_logger, statsd_logger
 from airflow_shared.observability.metrics.base_stats_logger import StatsLogger
 from airflow_shared.observability.metrics.datadog_logger import SafeDogStatsdLogger
+from airflow_shared.observability.metrics.stats import build_dag_metric_tags
 from airflow_shared.observability.metrics.statsd_logger import SafeStatsdLogger
 from airflow_shared.observability.metrics.validators import (
     PatternAllowListValidator,
@@ -259,6 +260,26 @@ def test_decr(self):
             metric="empty", sample_rate=1, value=1, tags=[]
         )
 
+    def test_key_value_tag_emitted_with_colon(self):
+        dogstatsd = SafeDogStatsdLogger(self.dogstatsd_client, metrics_tags=True)
+        dogstatsd.incr("my_metric", tags={"env": "prod"})
+        self.dogstatsd_client.increment.assert_called_once_with(
+            metric="my_metric", sample_rate=1, value=1, tags=["env:prod"]
+        )
+
+    def test_standalone_tag_empty_value_emitted_without_colon(self):
+        dogstatsd = SafeDogStatsdLogger(self.dogstatsd_client, metrics_tags=True)
+        dogstatsd.incr("my_metric", tags={"production": ""})
+        self.dogstatsd_client.increment.assert_called_once_with(
+            metric="my_metric", sample_rate=1, value=1, tags=["production"]
+        )
+
+    def test_mixed_tags_standalone_and_key_value(self):
+        dogstatsd = SafeDogStatsdLogger(self.dogstatsd_client, metrics_tags=True)
+        dogstatsd.incr("my_metric", tags={"production": "", "env": "staging"})
+        call_kwargs = self.dogstatsd_client.increment.call_args
+        assert set(call_kwargs.kwargs["tags"]) == {"production", "env:staging"}
+
 
 class TestStatsAllowAndBlockLists:
     @pytest.mark.parametrize(
@@ -475,6 +496,12 @@ def test_does_not_increment_counter_drops_invalid_tags(self):
         )
         self.statsd_client.incr.assert_called_once_with("test_stats_run.delay,key1=val1", 1, 1)
 
+    def test_standalone_tag_empty_value_emitted_as_true(self):
+        self.stats.incr("test_stats_run.delay", tags={"production": "", "key1": "val1"})
+        self.statsd_client.incr.assert_called_once_with(
+            "test_stats_run.delay,production=true,key1=val1", 1, 1
+        )
+
 
 def always_invalid(stat_name):
     raise InvalidStatsNameException(f"Invalid name: {stat_name}")
@@ -769,3 +796,26 @@ def test_does_send_stats_using_dogstatsd_when_the_name_is_valid(self):
     def teardown_method(self) -> None:
         # To avoid side-effect
         importlib.reload(airflow_shared.observability.metrics.stats)
+
+
+@pytest.mark.parametrize(
+    ("tag_names", "expected"),
+    [
+        pytest.param([], {}, id="empty"),
+        pytest.param(["production"], {"production": ""}, id="standalone"),
+        pytest.param(["env:prod"], {"env": "prod"}, id="key-value"),
+        pytest.param(
+            ["production", "env:prod", "team:data"],
+            {"production": "", "env": "prod", "team": "data"},
+            id="mixed",
+        ),
+        pytest.param(["a:b:c"], {"a": "b:c"}, id="value-with-colon"),
+        pytest.param(["env:"], {"env": ""}, id="trailing-colon-is-standalone"),
+    ],
+)
+def test_build_dag_metric_tags(tag_names: list[str], expected: dict[str, str]) -> None:
+    assert build_dag_metric_tags(tag_names) == expected
+
+
+def test_build_dag_metric_tags_accepts_generator() -> None:
+    assert build_dag_metric_tags(name for name in ["env:prod"]) == {"env": "prod"}
diff --git a/task-sdk/src/airflow/sdk/execution_time/task_runner.py b/task-sdk/src/airflow/sdk/execution_time/task_runner.py
index 94363b984b7f6..2e892812188d1 100644
--- a/task-sdk/src/airflow/sdk/execution_time/task_runner.py
+++ b/task-sdk/src/airflow/sdk/execution_time/task_runner.py
@@ -45,6 +45,7 @@
 from airflow.dag_processing.bundles.base import BaseDagBundle, BundleVersionLock
 from airflow.dag_processing.bundles.manager import DagBundlesManager
 from airflow.sdk._shared.observability.metrics import stats
+from airflow.sdk._shared.observability.metrics.stats import build_dag_metric_tags
 from airflow.sdk._shared.observability.traces import get_task_span_detail_level
 from airflow.sdk._shared.template_rendering import truncate_rendered_value
 from airflow.sdk.api.client import get_hostname, getuser
@@ -254,10 +255,21 @@ class RuntimeTaskInstance(TaskInstance):
 
     @property
     def stats_tags(self) -> dict[str, str]:
-        """Metric tags for this task instance, including team_name when available."""
-        tags: dict[str, str] = {"dag_id": self.dag_id, "task_id": self.task_id}
-        if self._ti_context_from_server and self._ti_context_from_server.dag_run.team_name:
-            tags["team_name"] = self._ti_context_from_server.dag_run.team_name
+        """Metric tags for this task instance, including dag tags and team_name when available."""
+        tags: dict[str, str] = {}
+        if conf.getboolean("metrics", "dag_tags_in_metrics", fallback=False):
+            tags.update(build_dag_metric_tags(self.task.dag.tags))
+        # Built-in keys always win on collision.
+        tags["dag_id"] = self.dag_id
+        tags["task_id"] = self.task_id
+        if self._ti_context_from_server:
+            # run_type keeps the tag set consistent with the scheduler-side TaskInstance.stats_tags.
+            # Coerce the DagRunType enum to its bare value so it serializes as e.g. "scheduled" rather
+            # than "dagruntype.scheduled" (matching the scheduler, which emits the plain string).
+            run_type = self._ti_context_from_server.dag_run.run_type
+            tags["run_type"] = getattr(run_type, "value", run_type)
+            if self._ti_context_from_server.dag_run.team_name:
+                tags["team_name"] = self._ti_context_from_server.dag_run.team_name
         return tags
 
     def __rich_repr__(self):
diff --git a/task-sdk/tests/task_sdk/execution_time/test_task_runner.py b/task-sdk/tests/task_sdk/execution_time/test_task_runner.py
index 9d15ac40c6967..fae8b9eb1f776 100644
--- a/task-sdk/tests/task_sdk/execution_time/test_task_runner.py
+++ b/task-sdk/tests/task_sdk/execution_time/test_task_runner.py
@@ -5434,11 +5434,11 @@ def test_ti_start_metric_emitted(self, create_runtime_ti, mock_supervisor_comms)
             run(ti, context=ti.get_template_context(), log=mock.MagicMock())
 
             # verify ti.start was called in legacy format
-            backend.incr.assert_any_call(f"ti.start.{ti.dag_id}.{ti.task_id}")
+            backend.incr.assert_any_call(f"ti.start.{ti.dag_id}.{ti.task_id}", tags={"run_type": "manual"})
             # verify ti.start was called in tagged format
             backend.incr.assert_any_call(
                 "ti.start",
-                tags={"dag_id": ti.dag_id, "task_id": ti.task_id},
+                tags={"dag_id": ti.dag_id, "task_id": ti.task_id, "run_type": "manual"},
             )
 
     @pytest.mark.parametrize(
@@ -5463,11 +5463,18 @@ def test_ti_finish_metric_emitted_for_terminal_states(
             run(ti, context=ti.get_template_context(), log=mock.MagicMock())
 
             # verify ti.finish was called in legacy format
-            backend.incr.assert_any_call(f"ti.finish.{ti.dag_id}.{ti.task_id}.{expected_state}")
+            backend.incr.assert_any_call(
+                f"ti.finish.{ti.dag_id}.{ti.task_id}.{expected_state}", tags={"run_type": "manual"}
+            )
             # verify ti.finish was called in tagged format
             backend.incr.assert_any_call(
                 "ti.finish",
-                tags={"dag_id": ti.dag_id, "task_id": ti.task_id, "state": expected_state},
+                tags={
+                    "dag_id": ti.dag_id,
+                    "task_id": ti.task_id,
+                    "run_type": "manual",
+                    "state": expected_state,
+                },
             )
 
     def test_operator_successes_metrics_emitted(self, create_runtime_ti, mock_supervisor_comms):
@@ -5480,7 +5487,7 @@ def test_operator_successes_metrics_emitted(self, create_runtime_ti, mock_superv
             mock_get_backend.return_value = backend
             run(ti, context=ti.get_template_context(), log=mock.MagicMock())
 
-            stats_tags = {"dag_id": ti.dag_id, "task_id": ti.task_id}
+            stats_tags = {"dag_id": ti.dag_id, "task_id": ti.task_id, "run_type": "manual"}
 
             # verify operator_successes in legacy format
             backend.incr.assert_any_call("operator_successes_PythonOperator", tags=stats_tags)
@@ -5501,7 +5508,7 @@ def test_operator_failures_metrics_emitted(self, create_runtime_ti, mock_supervi
             mock_get_backend.return_value = backend
             run(ti, context=ti.get_template_context(), log=mock.MagicMock())
 
-            stats_tags = {"dag_id": ti.dag_id, "task_id": ti.task_id}
+            stats_tags = {"dag_id": ti.dag_id, "task_id": ti.task_id, "run_type": "manual"}
 
             # verify operator_failures in legacy format
             backend.incr.assert_any_call("operator_failures_PythonOperator", tags=stats_tags)
@@ -5532,7 +5539,12 @@ def test_ti_start_metric_respects_team_name(
             mock_get_backend.return_value = backend
             run(ti, context=ti.get_template_context(), log=mock.MagicMock())
 
-            expected = {"dag_id": ti.dag_id, "task_id": ti.task_id, **expected_tags_extra}
+            expected = {
+                "dag_id": ti.dag_id,
+                "task_id": ti.task_id,
+                "run_type": "manual",
+                **expected_tags_extra,
+            }
             backend.incr.assert_any_call("ti.start", tags=expected)
 
     @pytest.mark.parametrize(
@@ -5554,7 +5566,12 @@ def test_operator_metrics_respect_team_name(
             mock_get_backend.return_value = backend
             run(ti, context=ti.get_template_context(), log=mock.MagicMock())
 
-            stats_tags = {"dag_id": ti.dag_id, "task_id": ti.task_id, "team_name": "team_a"}
+            stats_tags = {
+                "dag_id": ti.dag_id,
+                "task_id": ti.task_id,
+                "run_type": "manual",
+                "team_name": "team_a",
+            }
             backend.incr.assert_any_call(
                 operator_metric,
                 tags={**stats_tags, "operator_name": "PythonOperator"},
@@ -6343,3 +6360,49 @@ def test_bad_declaration_is_skipped_not_fatal(self):
         with patch("airflow.sdk.execution_time.task_runner.allow_class", side_effect=ValueError("nope")):
             # Must not raise -- the walk swallows per-class registration errors.
             _register_deserialization_allowed_classes(dag, structlog.get_logger())
+
+
+def _make_dag_tagged_ti(create_runtime_ti, tags):
+    """Build a RuntimeTaskInstance whose in-memory Dag carries the given tags."""
+    from airflow.sdk import DAG
+    from airflow.sdk.bases.operator import BaseOperator
+
+    class _NoopOperator(BaseOperator):
+        def execute(self, context):
+            return None
+
+    with DAG("tagged_dag", tags=tags):
+        task = _NoopOperator(task_id="t")
+    return create_runtime_ti(task=task)
+
+
+def test_stats_tags_dag_tags_disabled_by_default(create_runtime_ti):
+    """With the flag off (the default), dag tags must not leak into metrics."""
+    ti = _make_dag_tagged_ti(create_runtime_ti, ["env:prod", "validation"])
+    assert ti.stats_tags == {"dag_id": "tagged_dag", "task_id": "t", "run_type": "manual"}
+
+
+@conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+def test_stats_tags_without_dag_tags(create_runtime_ti):
+    ti = _make_dag_tagged_ti(create_runtime_ti, [])
+    assert ti.stats_tags == {"dag_id": "tagged_dag", "task_id": "t", "run_type": "manual"}
+
+
+@conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
+def test_stats_tags_with_standalone_and_key_value_tags(create_runtime_ti):
+    ti = _make_dag_tagged_ti(create_runtime_ti, ["env:prod", "validation"])
+    assert ti.stats_tags == {
+        "env": "prod",
+        "validation": "",
+        "dag_id": "tagged_dag",
+        "task_id": "t",
+        "run_type": "manual",
+    }
+
+
+def test_stats_tags_run_type_is_bare_string(create_runtime_ti):
+    """run_type must be the bare DagRunType value (e.g. 'manual'), not the enum — otherwise it
+    serializes as 'dagruntype.manual' on the wire and disagrees with the scheduler-side tag."""
+    run_type = _make_dag_tagged_ti(create_runtime_ti, []).stats_tags["run_type"]
+    assert run_type == "manual"
+    assert type(run_type) is str  # plain str, not a DagRunType enum member

From f7bd9bc9a59a56fb57736dcdb5e2d0f21e9aa643 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastia=CC=81n=20Ortega?=
 <sebastian.ortegatorres@datadoghq.com>
Date: Thu, 9 Jul 2026 12:10:48 +0200
Subject: [PATCH 2/4] Address review feedback on Dag tags metric emission

Keep the scheduler hot path free of per-task conf reads. Warm the dag tags via the existing
TaskInstance -> DagModel join rather than an extra dag_run hop, since the
DagModel is shared in the identity map. Fold the repeated dogstatsd tag-list
guard into a single helper, and consolidate the tag-formatting tests.
---
 .../src/airflow/jobs/scheduler_job_runner.py  | 26 ++++--
 airflow-core/src/airflow/models/dagrun.py     | 12 +--
 airflow-core/tests/unit/models/test_dagrun.py | 14 ++--
 .../observability/metrics/datadog_logger.py   | 40 +++-------
 .../tests/observability/metrics/test_stats.py | 80 +++++++++----------
 .../airflow/sdk/execution_time/task_runner.py |  3 +-
 .../execution_time/test_task_runner.py        | 21 ++---
 7 files changed, 91 insertions(+), 105 deletions(-)

diff --git a/airflow-core/src/airflow/jobs/scheduler_job_runner.py b/airflow-core/src/airflow/jobs/scheduler_job_runner.py
index 96710b81cc4e2..27b07ac5bbd42 100644
--- a/airflow-core/src/airflow/jobs/scheduler_job_runner.py
+++ b/airflow-core/src/airflow/jobs/scheduler_job_runner.py
@@ -334,6 +334,7 @@ def __init__(
         self._scheduler_use_job_schedule = conf.getboolean("scheduler", "use_job_schedule", fallback=True)
         self._parallelism = conf.getint("core", "parallelism")
         self._multi_team = conf.getboolean("core", "multi_team")
+        self._dag_tags_in_metrics = conf.getboolean("metrics", "dag_tags_in_metrics", fallback=False)
         self._max_partition_dag_runs_per_loop = MAX_PARTITION_DAG_RUNS_PER_LOOP
         self._dag_id_to_team_name: dict[str, str | None] = {}
 
@@ -1260,6 +1261,7 @@ def _process_executor_events(self, executor: BaseExecutor, session: Session) ->
                 job_id=self.job.id,
                 scheduler_dag_bag=self.scheduler_dag_bag,
                 session=session,
+                eagerly_load_dag_tags=self._dag_tags_in_metrics,
             )
         except Exception as exc:
             stats.incr("scheduler.executor_events.failed", tags={"exception_class": type(exc).__name__})
@@ -1272,7 +1274,12 @@ def _emit_executor_events_batch_metrics(num_events: int) -> None:
 
     @classmethod
     def process_executor_events(
-        cls, executor: BaseExecutor, job_id: int | None, scheduler_dag_bag: DBDagBag, session: Session
+        cls,
+        executor: BaseExecutor,
+        job_id: int | None,
+        scheduler_dag_bag: DBDagBag,
+        session: Session,
+        eagerly_load_dag_tags: bool = False,
     ) -> int:
         """
         Process task completion events from the executor and update task instance states.
@@ -1295,6 +1302,9 @@ def process_executor_events(
         :param job_id: The scheduler job ID, used to detect task requeuing by other schedulers
         :param scheduler_dag_bag: Serialized DAG bag for retrieving task definitions
         :param session: Database session for task instance updates
+        :param eagerly_load_dag_tags: When True, eager-load dag_model.tags so the per-finished-task
+            metrics carry Dag tags without a per-TI lazy load. The scheduler passes its cached flag so
+            the hot path never reads conf; other callers (e.g. ``dag.test()``) leave it at the default.
 
         :return: Number of events processed from the executor event buffer
 
@@ -1388,10 +1398,10 @@ def process_executor_events(
         )
         # When emitting Dag tags as metric tags, eager-load dag_model.tags so the per-finished-task
         # ti_failures / operator_failures / task.*_duration metrics carry them without a per-TI lazy load.
-        if conf.getboolean("metrics", "dag_tags_in_metrics", fallback=False):
-            query = query.options(
-                joinedload(TI.dag_run).joinedload(DagRun.dag_model).selectinload(DagModel.tags)
-            )
+        # TI already joins DagModel by dag_id, so warm tags off that relationship directly rather than
+        # via the dag_run hop; the DagModel is shared in the identity map, so dag_run.dag_model.tags is free.
+        if eagerly_load_dag_tags:
+            query = query.options(selectinload(TI.dag_model).selectinload(DagModel.tags))
         # row lock this entire set of taskinstances to make sure the scheduler doesn't fail when we have
         # multi-schedulers
         locked_query = with_row_locks(query, of=TI, session=session, skip_locked=True)
@@ -1928,7 +1938,11 @@ def _do_scheduling(self, session: Session) -> int:
             # examining, rather than making one query per DagRun.
             # Materialize into a list because the multi-team block below iterates
             # the result and ScalarResult is a one-pass iterator.
-            dag_runs = list(DagRun.get_running_dag_runs_to_examine(session=session))
+            dag_runs = list(
+                DagRun.get_running_dag_runs_to_examine(
+                    session=session, eagerly_load_dag_tags=self._dag_tags_in_metrics
+                )
+            )
 
             if self._multi_team and dag_runs:
                 unique_dag_ids = {dr.dag_id for dr in dag_runs}
diff --git a/airflow-core/src/airflow/models/dagrun.py b/airflow-core/src/airflow/models/dagrun.py
index b61dfdc425e40..d16998bcc048b 100644
--- a/airflow-core/src/airflow/models/dagrun.py
+++ b/airflow-core/src/airflow/models/dagrun.py
@@ -736,7 +736,9 @@ def active_runs_of_dags(
 
     @classmethod
     @retry_db_transaction
-    def get_running_dag_runs_to_examine(cls, session: Session) -> ScalarResult[DagRun]:
+    def get_running_dag_runs_to_examine(
+        cls, session: Session, *, eagerly_load_dag_tags: bool
+    ) -> ScalarResult[DagRun]:
         """
         Return the next DagRuns that the scheduler should attempt to schedule.
 
@@ -767,10 +769,10 @@ def get_running_dag_runs_to_examine(cls, session: Session) -> ScalarResult[DagRu
             .limit(cls.DEFAULT_DAGRUNS_TO_EXAMINE)
         )
 
-        # When dag tags are emitted as metric tags, eagerly load dag_model.tags so stats_tags
-        # does not fire a per-DagRun N+1 lazy load in the scheduler loop. Off by default, so the
-        # extra load is only paid when the feature is enabled.
-        if airflow_conf.getboolean("metrics", "dag_tags_in_metrics", fallback=False):
+        # When dag tags are emitted as metric tags, eagerly load dag_model.tags so stats_tags does not
+        # fire a per-DagRun N+1 lazy load in the scheduler loop. The caller owns the feature decision;
+        # the scheduler passes its cached flag so the loop never reads conf.
+        if eagerly_load_dag_tags:
             query = query.options(joinedload(cls.dag_model).selectinload(DagModel.tags))
 
         query = query.where(DagRun.run_after <= func.now())
diff --git a/airflow-core/tests/unit/models/test_dagrun.py b/airflow-core/tests/unit/models/test_dagrun.py
index 5e0d517de625c..c4e179afc9960 100644
--- a/airflow-core/tests/unit/models/test_dagrun.py
+++ b/airflow-core/tests/unit/models/test_dagrun.py
@@ -21,7 +21,7 @@
 from collections import defaultdict
 from collections.abc import Mapping
 from contextlib import contextmanager
-from functools import reduce
+from functools import partial, reduce
 from typing import TYPE_CHECKING
 from unittest import mock
 from unittest.mock import ANY, call
@@ -1086,10 +1086,10 @@ def test_next_dagruns_to_examine_only_unpaused(self, session, state, testing_dag
         )
 
         if state == DagRunState.RUNNING:
-            func = DagRun.get_running_dag_runs_to_examine
+            fetch = partial(DagRun.get_running_dag_runs_to_examine, session, eagerly_load_dag_tags=False)
         else:
-            func = DagRun.get_queued_dag_runs_to_set_running
-        runs = func(session).all()
+            fetch = partial(DagRun.get_queued_dag_runs_to_set_running, session)
+        runs = fetch().all()
 
         assert runs == [dr]
 
@@ -1097,7 +1097,7 @@ def test_next_dagruns_to_examine_only_unpaused(self, session, state, testing_dag
         session.merge(orm_dag)
         session.commit()
 
-        runs = func(session).all()
+        runs = fetch().all()
         assert runs == []
 
     @mock.patch("airflow._shared.observability.metrics.stats.timing")
@@ -4664,7 +4664,9 @@ def test_get_running_dag_runs_to_examine_eager_loads_dag_tags(dag_maker, session
     session.commit()
 
     dr = next(
-        r for r in DagRun.get_running_dag_runs_to_examine(session=session) if r.dag_id == "eager_tag_dag"
+        r
+        for r in DagRun.get_running_dag_runs_to_examine(session=session, eagerly_load_dag_tags=True)
+        if r.dag_id == "eager_tag_dag"
     )
     # dag_model and its tags are already populated — no lazy load needed at metric-emission time.
     assert "dag_model" not in sa_inspect(dr).unloaded
diff --git a/shared/observability/src/airflow_shared/observability/metrics/datadog_logger.py b/shared/observability/src/airflow_shared/observability/metrics/datadog_logger.py
index 4a22c9b6c3666..b1fda8208aa5b 100644
--- a/shared/observability/src/airflow_shared/observability/metrics/datadog_logger.py
+++ b/shared/observability/src/airflow_shared/observability/metrics/datadog_logger.py
@@ -58,15 +58,13 @@ def __init__(
         self.stat_name_handler = stat_name_handler
         self.statsd_influxdb_enabled = statsd_influxdb_enabled
 
-    @staticmethod
-    def _build_tags_list(
-        tags: dict[str, str],
-        metric_tags_validator: Any,
-    ) -> list[str]:
+    def _build_tags_list(self, tags: dict[str, str] | None) -> list[str]:
+        if not (self.metrics_tags and isinstance(tags, dict)):
+            return []
         return [
             (f"{key}:{value}" if value != "" else key)
             for key, value in tags.items()
-            if metric_tags_validator.test(key)
+            if self.metric_tags_validator.test(key)
         ]
 
     @validate_stat
@@ -79,11 +77,7 @@ def incr(
         tags: dict[str, str] | None = None,
     ) -> None:
         """Increment stat."""
-        tags_list = (
-            self._build_tags_list(tags, self.metric_tags_validator)
-            if self.metrics_tags and isinstance(tags, dict)
-            else []
-        )
+        tags_list = self._build_tags_list(tags)
         if self.metrics_validator.test(stat):
             return self.dogstatsd.increment(metric=stat, value=count, tags=tags_list, sample_rate=rate)
         return None
@@ -98,11 +92,7 @@ def decr(
         tags: dict[str, str] | None = None,
     ) -> None:
         """Decrement stat."""
-        tags_list = (
-            self._build_tags_list(tags, self.metric_tags_validator)
-            if self.metrics_tags and isinstance(tags, dict)
-            else []
-        )
+        tags_list = self._build_tags_list(tags)
         if self.metrics_validator.test(stat):
             return self.dogstatsd.decrement(metric=stat, value=count, tags=tags_list, sample_rate=rate)
         return None
@@ -118,11 +108,7 @@ def gauge(
         tags: dict[str, str] | None = None,
     ) -> None:
         """Gauge stat."""
-        tags_list = (
-            self._build_tags_list(tags, self.metric_tags_validator)
-            if self.metrics_tags and isinstance(tags, dict)
-            else []
-        )
+        tags_list = self._build_tags_list(tags)
         if self.metrics_validator.test(stat):
             return self.dogstatsd.gauge(metric=stat, value=value, tags=tags_list, sample_rate=rate)
         return None
@@ -136,11 +122,7 @@ def timing(
         tags: dict[str, str] | None = None,
     ) -> None:
         """Stats timing."""
-        tags_list = (
-            self._build_tags_list(tags, self.metric_tags_validator)
-            if self.metrics_tags and isinstance(tags, dict)
-            else []
-        )
+        tags_list = self._build_tags_list(tags)
         if self.metrics_validator.test(stat):
             if isinstance(dt, datetime.timedelta):
                 dt = dt.total_seconds() * 1000.0
@@ -155,11 +137,7 @@ def timer(
         **kwargs,
     ) -> Timer:
         """Timer metric that can be cancelled."""
-        tags_list = (
-            self._build_tags_list(tags, self.metric_tags_validator)
-            if self.metrics_tags and isinstance(tags, dict)
-            else []
-        )
+        tags_list = self._build_tags_list(tags)
         if stat and self.metrics_validator.test(stat):
             return Timer(self.dogstatsd.timed(stat, tags=tags_list, **kwargs))
         return Timer()
diff --git a/shared/observability/tests/observability/metrics/test_stats.py b/shared/observability/tests/observability/metrics/test_stats.py
index ffef79108dc1a..25deeb114e03a 100644
--- a/shared/observability/tests/observability/metrics/test_stats.py
+++ b/shared/observability/tests/observability/metrics/test_stats.py
@@ -260,25 +260,19 @@ def test_decr(self):
             metric="empty", sample_rate=1, value=1, tags=[]
         )
 
-    def test_key_value_tag_emitted_with_colon(self):
-        dogstatsd = SafeDogStatsdLogger(self.dogstatsd_client, metrics_tags=True)
-        dogstatsd.incr("my_metric", tags={"env": "prod"})
-        self.dogstatsd_client.increment.assert_called_once_with(
-            metric="my_metric", sample_rate=1, value=1, tags=["env:prod"]
-        )
-
-    def test_standalone_tag_empty_value_emitted_without_colon(self):
-        dogstatsd = SafeDogStatsdLogger(self.dogstatsd_client, metrics_tags=True)
-        dogstatsd.incr("my_metric", tags={"production": ""})
-        self.dogstatsd_client.increment.assert_called_once_with(
-            metric="my_metric", sample_rate=1, value=1, tags=["production"]
-        )
-
-    def test_mixed_tags_standalone_and_key_value(self):
+    @pytest.mark.parametrize(
+        ("tags", "expected"),
+        [
+            ({"env": "prod"}, {"env:prod"}),
+            ({"production": ""}, {"production"}),
+            ({"production": "", "env": "staging"}, {"production", "env:staging"}),
+        ],
+    )
+    def test_key_value_and_standalone_tags(self, tags, expected):
         dogstatsd = SafeDogStatsdLogger(self.dogstatsd_client, metrics_tags=True)
-        dogstatsd.incr("my_metric", tags={"production": "", "env": "staging"})
+        dogstatsd.incr("my_metric", tags=tags)
         call_kwargs = self.dogstatsd_client.increment.call_args
-        assert set(call_kwargs.kwargs["tags"]) == {"production", "env:staging"}
+        assert set(call_kwargs.kwargs["tags"]) == expected
 
 
 class TestStatsAllowAndBlockLists:
@@ -478,29 +472,35 @@ def test_increment_counter(self):
         )
         self.statsd_client.incr.assert_called_once_with("test_stats_run.delay", 1, 1)
 
-    def test_increment_counter_with_tags(self):
-        self.stats.incr(
-            "test_stats_run.delay",
-            tags={"key0": 0, "key1": "val1", "key2": "val2"},
-        )
-        self.statsd_client.incr.assert_called_once_with("test_stats_run.delay,key0=0,key1=val1", 1, 1)
-
-    def test_increment_counter_with_tags_and_forward_slash(self):
-        self.stats.incr("test_stats_run.dag", tags={"path": "/some/path/dag.py"})
-        self.statsd_client.incr.assert_called_once_with("test_stats_run.dag,path=/some/path/dag.py", 1, 1)
-
-    def test_does_not_increment_counter_drops_invalid_tags(self):
-        self.stats.incr(
-            "test_stats_run.delay",
-            tags={"key0,": "val0", "key1": "val1", "key2": "val2", "key3": "val3"},
-        )
-        self.statsd_client.incr.assert_called_once_with("test_stats_run.delay,key1=val1", 1, 1)
-
-    def test_standalone_tag_empty_value_emitted_as_true(self):
-        self.stats.incr("test_stats_run.delay", tags={"production": "", "key1": "val1"})
-        self.statsd_client.incr.assert_called_once_with(
-            "test_stats_run.delay,production=true,key1=val1", 1, 1
-        )
+    @pytest.mark.parametrize(
+        ("stat", "tags", "expected"),
+        [
+            (
+                "test_stats_run.delay",
+                {"key0": 0, "key1": "val1", "key2": "val2"},
+                "test_stats_run.delay,key0=0,key1=val1",
+            ),
+            (
+                "test_stats_run.dag",
+                {"path": "/some/path/dag.py"},
+                "test_stats_run.dag,path=/some/path/dag.py",
+            ),
+            (
+                "test_stats_run.delay",
+                {"key0,": "val0", "key1": "val1", "key2": "val2", "key3": "val3"},
+                "test_stats_run.delay,key1=val1",
+            ),
+            # Empty value renders as `=true` in influxdb line protocol.
+            (
+                "test_stats_run.delay",
+                {"production": "", "key1": "val1"},
+                "test_stats_run.delay,production=true,key1=val1",
+            ),
+        ],
+    )
+    def test_increment_counter_with_tags(self, stat, tags, expected):
+        self.stats.incr(stat, tags=tags)
+        self.statsd_client.incr.assert_called_once_with(expected, 1, 1)
 
 
 def always_invalid(stat_name):
diff --git a/task-sdk/src/airflow/sdk/execution_time/task_runner.py b/task-sdk/src/airflow/sdk/execution_time/task_runner.py
index 2e892812188d1..7fb29e37a2728 100644
--- a/task-sdk/src/airflow/sdk/execution_time/task_runner.py
+++ b/task-sdk/src/airflow/sdk/execution_time/task_runner.py
@@ -260,8 +260,7 @@ def stats_tags(self) -> dict[str, str]:
         if conf.getboolean("metrics", "dag_tags_in_metrics", fallback=False):
             tags.update(build_dag_metric_tags(self.task.dag.tags))
         # Built-in keys always win on collision.
-        tags["dag_id"] = self.dag_id
-        tags["task_id"] = self.task_id
+        tags.update(dag_id=self.dag_id, task_id=self.task_id)
         if self._ti_context_from_server:
             # run_type keeps the tag set consistent with the scheduler-side TaskInstance.stats_tags.
             # Coerce the DagRunType enum to its bare value so it serializes as e.g. "scheduled" rather
diff --git a/task-sdk/tests/task_sdk/execution_time/test_task_runner.py b/task-sdk/tests/task_sdk/execution_time/test_task_runner.py
index fae8b9eb1f776..ce70760f83396 100644
--- a/task-sdk/tests/task_sdk/execution_time/test_task_runner.py
+++ b/task-sdk/tests/task_sdk/execution_time/test_task_runner.py
@@ -6367,12 +6367,8 @@ def _make_dag_tagged_ti(create_runtime_ti, tags):
     from airflow.sdk import DAG
     from airflow.sdk.bases.operator import BaseOperator
 
-    class _NoopOperator(BaseOperator):
-        def execute(self, context):
-            return None
-
     with DAG("tagged_dag", tags=tags):
-        task = _NoopOperator(task_id="t")
+        task = BaseOperator(task_id="t")
     return create_runtime_ti(task=task)
 
 
@@ -6384,8 +6380,11 @@ def test_stats_tags_dag_tags_disabled_by_default(create_runtime_ti):
 
 @conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
 def test_stats_tags_without_dag_tags(create_runtime_ti):
-    ti = _make_dag_tagged_ti(create_runtime_ti, [])
-    assert ti.stats_tags == {"dag_id": "tagged_dag", "task_id": "t", "run_type": "manual"}
+    tags = _make_dag_tagged_ti(create_runtime_ti, []).stats_tags
+    assert tags == {"dag_id": "tagged_dag", "task_id": "t", "run_type": "manual"}
+    # run_type must be a plain str, not a DagRunType enum member: DagRunType is a str-enum, so the
+    # dict equality above passes either way, but the enum serializes as "dagruntype.manual" on the wire.
+    assert type(tags["run_type"]) is str
 
 
 @conf_vars({("metrics", "dag_tags_in_metrics"): "True"})
@@ -6398,11 +6397,3 @@ def test_stats_tags_with_standalone_and_key_value_tags(create_runtime_ti):
         "task_id": "t",
         "run_type": "manual",
     }
-
-
-def test_stats_tags_run_type_is_bare_string(create_runtime_ti):
-    """run_type must be the bare DagRunType value (e.g. 'manual'), not the enum — otherwise it
-    serializes as 'dagruntype.manual' on the wire and disagrees with the scheduler-side tag."""
-    run_type = _make_dag_tagged_ti(create_runtime_ti, []).stats_tags["run_type"]
-    assert run_type == "manual"
-    assert type(run_type) is str  # plain str, not a DagRunType enum member

From e864f59acad8cc27a240ab2886c96b25f9d187d3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastia=CC=81n=20Ortega?=
 <sebastian.ortegatorres@datadoghq.com>
Date: Tue, 14 Jul 2026 17:45:42 +0200
Subject: [PATCH 3/4] Address further review nits on Dag tags metric emission

Make session a keyword-only argument on get_running_dag_runs_to_examine, in
line with the convention for session parameters. Reduce TaskInstance.stats_tags
to the dag run's tags plus the task-level ones, keeping the TI's transiently
resolved team_name when present.
---
 airflow-core/src/airflow/models/dagrun.py     |  2 +-
 .../src/airflow/models/taskinstance.py        | 21 +++++++------------
 airflow-core/tests/unit/models/test_dagrun.py |  4 +++-
 3 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/airflow-core/src/airflow/models/dagrun.py b/airflow-core/src/airflow/models/dagrun.py
index d16998bcc048b..d6610b3663e7e 100644
--- a/airflow-core/src/airflow/models/dagrun.py
+++ b/airflow-core/src/airflow/models/dagrun.py
@@ -737,7 +737,7 @@ def active_runs_of_dags(
     @classmethod
     @retry_db_transaction
     def get_running_dag_runs_to_examine(
-        cls, session: Session, *, eagerly_load_dag_tags: bool
+        cls, *, session: Session, eagerly_load_dag_tags: bool
     ) -> ScalarResult[DagRun]:
         """
         Return the next DagRuns that the scheduler should attempt to schedule.
diff --git a/airflow-core/src/airflow/models/taskinstance.py b/airflow-core/src/airflow/models/taskinstance.py
index 6a277e2710d2b..465df5fa62a36 100644
--- a/airflow-core/src/airflow/models/taskinstance.py
+++ b/airflow-core/src/airflow/models/taskinstance.py
@@ -100,7 +100,6 @@
 from airflow.ti_deps.dep_context import DepContext
 from airflow.ti_deps.dependencies_deps import REQUEUEABLE_DEPS, RUNNING_DEPS
 from airflow.ti_deps.deps.ready_to_reschedule import ReadyToRescheduleDep
-from airflow.utils.helpers import prune_dict
 from airflow.utils.log.logging_mixin import LoggingMixin
 from airflow.utils.net import get_hostname
 from airflow.utils.platform import getuser
@@ -757,19 +756,13 @@ def __hash__(self):
     @property
     def stats_tags(self) -> dict[str, str]:
         """Returns task instance tags."""
-        run_type = self.dag_run.run_type
-        base = prune_dict(
-            {
-                "dag_id": self.dag_id,
-                "task_id": self.task_id,
-                # bare value so it serializes as e.g. "scheduled", not "dagruntype.scheduled"
-                "run_type": getattr(run_type, "value", run_type),
-                "team_name": getattr(self, "_team_name", None),
-            }
-        )
-        dag_tags = self.dag_run.dag_tags_for_stats()
-        # Built-in keys win on collision; dag tags fill in everything else.
-        return {**dag_tags, **base}
+        # Reuse the dag run's tags (dag_id, run_type, dag tags) and add the task-level ones.
+        # team_name is a transient attribute resolved per-object at scheduling time, so it may be set
+        # on the TI even when the dag run has not seen it — carry the TI's own value when present.
+        tags = {**self.dag_run.stats_tags, "task_id": self.task_id}
+        if team_name := getattr(self, "_team_name", None):
+            tags["team_name"] = team_name
+        return tags
 
     @staticmethod
     def insert_mapping(
diff --git a/airflow-core/tests/unit/models/test_dagrun.py b/airflow-core/tests/unit/models/test_dagrun.py
index c4e179afc9960..c46c30d1194e6 100644
--- a/airflow-core/tests/unit/models/test_dagrun.py
+++ b/airflow-core/tests/unit/models/test_dagrun.py
@@ -1086,7 +1086,9 @@ def test_next_dagruns_to_examine_only_unpaused(self, session, state, testing_dag
         )
 
         if state == DagRunState.RUNNING:
-            fetch = partial(DagRun.get_running_dag_runs_to_examine, session, eagerly_load_dag_tags=False)
+            fetch = partial(
+                DagRun.get_running_dag_runs_to_examine, session=session, eagerly_load_dag_tags=False
+            )
         else:
             fetch = partial(DagRun.get_queued_dag_runs_to_set_running, session)
         runs = fetch().all()

From f8908a87a60a2527b8109854052fe61c2d767c37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastia=CC=81n=20Ortega?=
 <sebastian.ortegatorres@datadoghq.com>
Date: Fri, 17 Jul 2026 14:00:57 +0200
Subject: [PATCH 4/4] Source task instance team_name metric tag from the dag
 run

TaskInstance.stats_tags already reuses the dag run's stats tags, so take
team_name from there too rather than from a separate per-task transient
attribute, keeping a single source of truth for the tag.

The scheduling loop now stashes the resolved team on the dag run so
task-instance metrics still carry it. The heartbeat-purge path already tags
team inline, so its now-redundant per-task assignment is dropped.
---
 .../src/airflow/jobs/scheduler_job_runner.py  |  9 ++----
 .../src/airflow/models/taskinstance.py        |  9 ++----
 .../tests/unit/jobs/test_scheduler_job.py     | 31 +++++++++----------
 .../tests/unit/models/test_taskinstance.py    | 12 +++----
 4 files changed, 26 insertions(+), 35 deletions(-)

diff --git a/airflow-core/src/airflow/jobs/scheduler_job_runner.py b/airflow-core/src/airflow/jobs/scheduler_job_runner.py
index 27b07ac5bbd42..cf7c952075ac6 100644
--- a/airflow-core/src/airflow/jobs/scheduler_job_runner.py
+++ b/airflow-core/src/airflow/jobs/scheduler_job_runner.py
@@ -737,10 +737,10 @@ def _executable_task_instances_to_queued(self, max_tis: int, session: Session) -
                     list(unique_dag_ids),
                 )
                 for ti in task_instances_to_examine:
-                    # Set team as a transient attribute; team lives on the Bundle, not
-                    # on the TI/DagRun schema, so we resolve it at scheduling time.
+                    # Team lives on the Bundle, not the TI/DagRun schema, so resolve it at scheduling
+                    # time and stash it on the dag run, where stats_tags reads it for metric tagging.
                     if team := dag_id_to_team_name.get(ti.dag_id):
-                        ti._team_name = team
+                        ti.dag_run._team_name = team
 
             executor_slots_available: dict[ExecutorName, int] = {}
             # First get a mapping of executor names to slots they have available
@@ -3573,9 +3573,6 @@ def _purge_task_instances_without_heartbeats(
         if self._multi_team:
             unique_dag_ids = {ti.dag_id for ti in task_instances_without_heartbeats}
             dag_id_to_team_name = self._get_team_names_for_dag_ids(unique_dag_ids, session)
-            for ti in task_instances_without_heartbeats:
-                if team := dag_id_to_team_name.get(ti.dag_id):
-                    ti._team_name = team
         else:
             dag_id_to_team_name = {}
 
diff --git a/airflow-core/src/airflow/models/taskinstance.py b/airflow-core/src/airflow/models/taskinstance.py
index 465df5fa62a36..0dd10507fc863 100644
--- a/airflow-core/src/airflow/models/taskinstance.py
+++ b/airflow-core/src/airflow/models/taskinstance.py
@@ -756,13 +756,8 @@ def __hash__(self):
     @property
     def stats_tags(self) -> dict[str, str]:
         """Returns task instance tags."""
-        # Reuse the dag run's tags (dag_id, run_type, dag tags) and add the task-level ones.
-        # team_name is a transient attribute resolved per-object at scheduling time, so it may be set
-        # on the TI even when the dag run has not seen it — carry the TI's own value when present.
-        tags = {**self.dag_run.stats_tags, "task_id": self.task_id}
-        if team_name := getattr(self, "_team_name", None):
-            tags["team_name"] = team_name
-        return tags
+        # Reuse the dag run's tags and add the task-level ones.
+        return {**self.dag_run.stats_tags, "task_id": self.task_id}
 
     @staticmethod
     def insert_mapping(
diff --git a/airflow-core/tests/unit/jobs/test_scheduler_job.py b/airflow-core/tests/unit/jobs/test_scheduler_job.py
index 2e89843c7fa62..3c0664db66aa6 100644
--- a/airflow-core/tests/unit/jobs/test_scheduler_job.py
+++ b/airflow-core/tests/unit/jobs/test_scheduler_job.py
@@ -9801,8 +9801,10 @@ def test_multi_team_config_disabled_uses_legacy_behavior(self, dag_maker, mock_e
             assert result2 == mock_executors[1]  # Matched by executor name
 
     @conf_vars({("core", "multi_team"): "true"})
-    def test_multi_team_sets_team_name_on_task_instances(self, dag_maker, mock_executors, session):
-        """Test that _team_name is set on TaskInstance objects during the scheduling loop."""
+    @mock.patch("airflow._shared.observability.metrics.stats.timing")
+    def test_multi_team_sets_team_name_on_task_instances(self, mock_timing, dag_maker, session):
+        """The scheduling loop resolves the bundle's team onto the dag run, so the QUEUED
+        state-change metric (emitted via TaskInstance.stats_tags) carries team_name."""
         clear_db_teams()
         clear_db_dag_bundles()
 
@@ -9821,24 +9823,21 @@ def test_multi_team_sets_team_name_on_task_instances(self, dag_maker, mock_execu
         dr = dag_maker.create_dagrun()
         ti = dr.get_task_instance("task_a", session=session)
         ti.state = State.SCHEDULED
+        ti.scheduled_dttm = timezone.utcnow()
+        session.merge(ti)
         session.flush()
 
         scheduler_job = Job()
         self.job_runner = SchedulerJobRunner(job=scheduler_job)
-        self.job_runner._multi_team = True
-
-        # Simulate what _executable_task_instances_to_queued does
-        dag_id_to_team_name = self.job_runner._get_team_names_for_dag_ids(["dag_a"], session)
-        if team_name := dag_id_to_team_name.get(ti.dag_id):
-            ti._team_name = team_name
-
-        assert ti._team_name == "team_a"
-        assert ti.stats_tags == {
-            "dag_id": "dag_a",
-            "task_id": "task_a",
-            "team_name": "team_a",
-            "run_type": dr.run_type,
-        }
+
+        queued_tis = self.job_runner._executable_task_instances_to_queued(max_tis=32, session=session)
+
+        assert {t.key for t in queued_tis} == {ti.key}
+        scheduled_calls = [
+            c for c in mock_timing.call_args_list if c.args and c.args[0] == "task.scheduled_duration"
+        ]
+        assert scheduled_calls, "expected a task.scheduled_duration metric on QUEUED transition"
+        assert scheduled_calls[0].kwargs["tags"]["team_name"] == "team_a"
 
     @conf_vars({("core", "multi_team"): "true"})
     def test_do_scheduling_multi_team_schedules_task_instances(self, dag_maker, session):
diff --git a/airflow-core/tests/unit/models/test_taskinstance.py b/airflow-core/tests/unit/models/test_taskinstance.py
index 029764e9a942d..e0d4a1063e935 100644
--- a/airflow-core/tests/unit/models/test_taskinstance.py
+++ b/airflow-core/tests/unit/models/test_taskinstance.py
@@ -4374,7 +4374,7 @@ def test_task_instance_repr_does_not_raise_for_deferred_columns(dag_maker, sessi
 
 class TestTaskInstanceStatsTagsTeamName:
     def test_stats_tags_without_team_name(self, dag_maker, session):
-        """stats_tags should not include team_name when _team_name is not set."""
+        """stats_tags should not include team_name when the dag run has no team_name."""
         with dag_maker("test_dag"):
             EmptyOperator(task_id="my_task")
         dr = dag_maker.create_dagrun()
@@ -4384,12 +4384,12 @@ def test_stats_tags_without_team_name(self, dag_maker, session):
         assert tags == {"dag_id": "test_dag", "task_id": "my_task", "run_type": dr.run_type}
 
     def test_stats_tags_with_team_name(self, dag_maker, session):
-        """stats_tags should include team_name when _team_name is set."""
+        """stats_tags takes team_name from the dag run's stats_tags."""
         with dag_maker("test_dag"):
             EmptyOperator(task_id="my_task")
         dr = dag_maker.create_dagrun()
+        dr._team_name = "my_team"
         ti = dr.get_task_instance("my_task", session=session)
-        ti._team_name = "my_team"
         tags = ti.stats_tags
         assert tags["team_name"] == "my_team"
         assert tags == {
@@ -4400,12 +4400,12 @@ def test_stats_tags_with_team_name(self, dag_maker, session):
         }
 
     def test_stats_tags_with_none_team_name(self, dag_maker, session):
-        """stats_tags should not include team_name when _team_name is None."""
+        """stats_tags should not include team_name when the dag run's team_name is None."""
         with dag_maker("test_dag"):
             EmptyOperator(task_id="my_task")
         dr = dag_maker.create_dagrun()
+        dr._team_name = None
         ti = dr.get_task_instance("my_task", session=session)
-        ti._team_name = None
         tags = ti.stats_tags
         assert "team_name" not in tags
 
@@ -4465,7 +4465,7 @@ def test_emit_state_change_metric_includes_team_name(
         ti.state = TaskInstanceState.SCHEDULED
         ti.scheduled_dttm = timezone.utcnow()
         if team_name:
-            ti._team_name = team_name
+            dr._team_name = team_name
         session.merge(ti)
         session.flush()