diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/create.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/create.md
new file mode 100644
index 0000000000..d3373e9bed
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/create.md
@@ -0,0 +1,24 @@
+# Create operational intent reference test step fragment
+
+This test step fragment validates that operational intent references can be created
+
+## 🛑 Create operational intent reference query succeeds check
+
+As per **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**, the DSS API must allow callers to create an operational intent reference with either one or both of the
+start and end time missing, provided all the required parameters are valid.
+
+## 🛑 Create operational intent reference response is correct check
+
+A successful operational intent reference creation query is expected to return a well-defined body, the content of which reflects the created operational intent reference.
+If the format and content of the response are not conforming, the DSS is failing to implement **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Create operational intent reference response format conforms to spec check
+
+The response to a successful operational intent reference creation query is expected to conform to the format defined by the OpenAPI specification under the `A3.1` Annex of ASTM F3548−21.
+
+If it does not, the DSS is failing to implement **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Response to operational intent reference creation contains correct body check
+
+As per **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**, upon creation of a operational intent reference,
+the newly created operational intent reference must be part of its response.
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/delete.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/delete.md
new file mode 100644
index 0000000000..d48632d021
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/delete.md
@@ -0,0 +1,18 @@
+# Delete operational intent reference test step fragment
+
+This test step fragment validates that operational intent references can be deleted
+
+## 🛑 Delete operational intent reference query succeeds check
+
+A query to delete an operational intent reference, by its owner and when the correct OVN is provided, should succeed, otherwise the DSS is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Delete operational intent reference response is correct check
+
+A successful operational intent reference deletion query is expected to return a well-defined body, the content of which reflects the operational intent reference at the moment of deletion.
+If the format and content of the response are not conforming, the DSS is failing to implement **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Delete operational intent reference response format conforms to spec check
+
+The response to a successful operational intent reference deletion query is expected to conform to the format defined by the OpenAPI specification under the `A3.1` Annex of ASTM F3548−21.
+
+If it does not, the DSS is failing to implement **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/read.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/read.md
new file mode 100644
index 0000000000..3d06d6f69a
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/read.md
@@ -0,0 +1,27 @@
+# Read operational intent reference test step fragment
+
+This test step fragment validates that operational intent references can be read
+
+## 🛑 Get operational intent reference by ID check
+
+If an operational intent reference cannot be queried using its ID, the DSS is failing to meet **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Get operational intent reference response format conforms to spec check
+
+The response to a successful get operational intent reference query is expected to conform to the format defined by the OpenAPI specification under the `A3.1` Annex of ASTM F3548−21.
+
+If it does not, the DSS is failing to implement **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Successful operational intent reference search query check
+
+If the DSS fails to let us search in the area for which the OIR was created, it is failing to meet **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Created operational intent reference is in search results check
+
+If the existing operational intent reference is not returned in a search that covers the area it was created for, the DSS is not properly implementing **[astm.f3548.v21.DSS0005,2](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Search operational intent reference response format conforms to spec check
+
+The response to a successful operational intent reference search query is expected to conform to the format defined by the OpenAPI specification under the `A3.1` Annex of ASTM F3548−21.
+
+If it does not, the DSS is failing to implement **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/update.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/update.md
new file mode 100644
index 0000000000..3360563830
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/crud/update.md
@@ -0,0 +1,18 @@
+# Update operational intent reference test step fragment
+
+This test step fragment validates that operational intent references can be updated.
+
+## 🛑 Mutate operational intent reference query succeeds check
+
+As per **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**, the DSS API must allow callers to mutate an operational intent reference.
+
+## 🛑 Mutate operational intent reference query succeeds check
+
+A successful operational intent reference mutation query is expected to return a well-defined body, the content of which reflects the updated operational intent reference.
+If the format and content of the response are not conforming, the DSS is failing to implement **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Mutate operational intent reference response format conforms to spec check
+
+The response to a successful operational intent reference mutation query is expected to conform to the format defined by the OpenAPI specification under the `A3.1` Annex of ASTM F3548−21.
+
+If it does not, the DSS is failing to implement **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/sync.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/sync.md
new file mode 100644
index 0000000000..131d0a28a1
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/sync.md
@@ -0,0 +1,33 @@
+# Synchronize operational intent reference test step fragment
+
+This test step fragment validates that operational intent references are properly synchronized across a set of DSS instances.
+
+## 🛑 Operational intent reference can be found at every DSS check
+
+If the previously created or mutated operational intent reference cannot be found at a DSS, either one of the instances at which the operational intent reference was created or the one that was queried,
+may be failing to implement **[astm.f3548.v21.DSS0210,2a](../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Propagated operational intent reference contains the correct manager check
+
+If the operational intent reference returned by a DSS to which the operational intent reference was synchronized to does not contain the correct manager,
+either one of the instances at which the operational intent reference was created or the one that was queried, may be failing to implement **[astm.f3548.v21.DSS0210,2b](../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Propagated operational intent reference contains the correct USS base URL check
+
+If the operational intent reference returned by a DSS to which the operational intent reference was synchronized to does not contain the correct USS base URL,
+either one of the instances at which the operational intent reference was created or the one that was queried, may be failing to implement **[astm.f3548.v21.DSS0210,2c](../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Propagated operational intent reference contains the correct state check
+
+If the operational intent reference returned by a DSS to which the operational intent reference was synchronized to does not contain the correct state,
+either one of the instances at which the operational intent reference was created or the one that was queried, may be failing to implement **[astm.f3548.v21.DSS0210,2d](../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Propagated operational intent reference contains the correct start time check
+
+If the operational intent reference returned by a DSS to which the operational intent reference was synchronized to does not contain the correct start time,
+either one of the instances at which the operational intent reference was created or the one that was queried, may be failing to implement **[astm.f3548.v21.DSS0210,2f](../../../../../../requirements/astm/f3548/v21.md)**.
+
+## 🛑 Propagated operational intent reference contains the correct end time check
+
+If the operational intent reference returned by a DSS to which the operational intent reference was synchronized to does not contain the correct end time,
+either one of the instances at which the operational intent reference was created or the one that was queried, may be failing to implement **[astm.f3548.v21.DSS0210,2f](../../../../../../requirements/astm/f3548/v21.md)**.
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/correctness.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/correctness.md
new file mode 100644
index 0000000000..597be17494
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/correctness.md
@@ -0,0 +1,53 @@
+# Validate the content of an operational intent reference test step fragment
+
+This test step fragment attempts to validate the content of a single operational intent reference returned by the DSS.
+
+Fields that require different handling based on if the operational intent reference was mutated or not are covered
+
+The code for these checks lives in the [oir_validator.py](../../../validators/oir_validator.py) class.
+
+## ⚠️ Returned operational intent reference ID is correct check
+
+If the returned operational intent reference ID does not correspond to the one specified in the creation parameters,
+**[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)** is not respected.
+
+## ⚠️ Returned operational intent reference has a manager check
+
+If the returned operational intent reference has no manager defined, **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)** is not respected.
+
+## ⚠️ Returned operational intent reference manager is correct check
+
+The returned manager must correspond to the identity of the client that created the operational intent at the DSS,
+otherwise the DSS is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Returned operational intent reference state is correct check
+
+The returned state must be the same as the provided one, otherwise the DSS is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Returned operational intent reference has an USS base URL check
+
+If the returned operational intent reference has no USS base URL defined, **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)** is not respected.
+
+## ⚠️ Returned operational intent reference base URL is correct check
+
+The returned USS base URL must be prefixed with the USS base URL that was provided at operational intent reference creation, otherwise the DSS is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Returned operational intent reference has a start time check
+
+If the returned operational intent reference has no start time defined, **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)** is not respected.
+
+## ⚠️ Returned start time is correct check
+
+The returned start time must be the same as the provided one, otherwise the DSS is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Returned operational intent reference has an end time check
+
+Operational intent references need a defined end time in order to limit their duration: if the DSS omits to set the end time, it will be in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Returned end time is correct check
+
+The returned end time must be the same as the provided one, otherwise the DSS is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Returned operational intent reference has a version check
+
+If the returned operational intent reference has no version defined, **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)** is not respected.
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/mutated.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/mutated.md
new file mode 100644
index 0000000000..635a01dcf7
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/mutated.md
@@ -0,0 +1,14 @@
+# Validate mutated operational intent reference test step fragment
+
+This test step fragment attempts to validate a single operational intent reference returned by the DSS,
+usually after it has been mutated.
+
+The code for these checks lives in the [oir_validator.py](../../../validators/oir_validator.py) class.
+
+## ⚠️ Mutated operational intent reference version is updated check
+
+Following a mutation, the DSS needs to update the operational intent reference version, otherwise it is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Mutated operational intent reference OVN is updated check
+
+Following a mutation, the DSS needs to update the operational intent reference OVN, otherwise it is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/non_mutated.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/non_mutated.md
new file mode 100644
index 0000000000..f0b4687501
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/fragments/oir/validate/non_mutated.md
@@ -0,0 +1,14 @@
+# Validate non-mutated operational intent reference test step fragment
+
+This test step fragment attempts to validate a single operational intent reference returned by the DSS,
+usually after it has been created or to confirm it has not been mutated by an action.
+
+The code for these checks lives in the [oir_validator.py](../../../validators/oir_validator.py) class.
+
+## ⚠️ Non-mutated operational intent reference keeps the same version check
+
+If the version of the operational intent reference is updated without there having been any mutation of the operational intent reference, the DSS is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
+
+## ⚠️ Non-mutated operational intent reference keeps the same OVN check
+
+If the OVN of the operational intent reference is updated without there having been any mutation of the operational intent reference, the DSS is in violation of **[astm.f3548.v21.DSS0005,1](../../../../../../../requirements/astm/f3548/v21.md)**.
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/test_step_fragments.py b/monitoring/uss_qualifier/scenarios/astm/utm/dss/test_step_fragments.py
index 1cf30767cf..8649925af9 100644
--- a/monitoring/uss_qualifier/scenarios/astm/utm/dss/test_step_fragments.py
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/test_step_fragments.py
@@ -2,6 +2,7 @@
 
 import loguru
 
+from monitoring.monitorlib.fetch import QueryError
 from monitoring.monitorlib.mutate.scd import MutatedSubscription
 from monitoring.monitorlib import fetch
 from monitoring.uss_qualifier.resources.astm.f3548.v21.dss import DSSInstance
@@ -92,3 +93,27 @@ def cleanup_active_subs(
 
     for sub_id in query.subscriptions.keys():
         cleanup_sub(scenario, dss, sub_id)
+
+
+def cleanup_active_oirs(
+    scenario: TestScenarioType,
+    dss: DSSInstance,
+    volume: Volume4D,
+    manager_identity: str,
+) -> None:
+    with scenario.check(
+        "Operational intent references can be searched for", [dss.participant_id]
+    ) as check:
+        try:
+            oirs, query = dss.find_op_intent(volume)
+        except QueryError as qe:
+            scenario.record_queries(qe.queries)
+            check.record_failed(
+                summary="Failed to query operational intent references",
+                details=f"Failed to query operational intent references: got response code {qe.queries[0].status_code}",
+                query_timestamps=[qe.queries[0].request.timestamp],
+            )
+
+        for oir in oirs:
+            if oir.manager == manager_identity:
+                remove_op_intent(scenario, dss, oir.id, oir.ovn)
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/validators/oir_validator.py b/monitoring/uss_qualifier/scenarios/astm/utm/dss/validators/oir_validator.py
new file mode 100644
index 0000000000..f6b1bfc7af
--- /dev/null
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/validators/oir_validator.py
@@ -0,0 +1,505 @@
+from datetime import datetime
+from typing import Optional, List
+
+from implicitdict import ImplicitDict
+from uas_standards.astm.f3548.v21.api import (
+    PutOperationalIntentReferenceParameters,
+    EntityID,
+    OperationalIntentReference,
+    ChangeOperationalIntentReferenceResponse,
+    EntityOVN,
+    GetOperationalIntentReferenceResponse,
+    QueryOperationalIntentReferenceResponse,
+)
+
+from monitoring.monitorlib import schema_validation, fetch
+from monitoring.monitorlib.schema_validation import F3548_21
+from monitoring.uss_qualifier.scenarios.scenario import PendingCheck, TestScenario
+
+TIME_TOLERANCE_SEC = 1
+"""tolerance when comparing created vs returned timestamps"""
+
+
+class OIRValidator:
+    """
+    Wraps the validation logic for an operational intent reference that was returned by a DSS
+
+    It will compare the provided OIR with the parameters specified at its creation.
+    """
+
+    _main_check: PendingCheck
+    """
+    The overarching check corresponding to the general validation of an OIR.
+    This check will be failed if any of the sub-checks carried out by this validator fail.
+    """
+
+    _scenario: TestScenario
+    """
+    Scenario in which this validator is being used. Will be used to register checks.
+    """
+
+    _oir_params: Optional[PutOperationalIntentReferenceParameters]
+    _pid: List[str]
+    """Participant ID(s) to use for the checks"""
+
+    def __init__(
+        self,
+        main_check: PendingCheck,
+        scenario: TestScenario,
+        expected_manager: str,
+        participant_id: List[str],
+        oir_params: Optional[PutOperationalIntentReferenceParameters],
+    ):
+        self._main_check = main_check
+        self._scenario = scenario
+        self._pid = participant_id
+        self._oir_params = oir_params
+        self._expected_manager = expected_manager
+        self._expected_start = oir_params.extents[0].time_start.value.datetime
+        self._expected_end = oir_params.extents[-1].time_end.value.datetime
+
+    def _fail_sub_check(
+        self, sub_check: PendingCheck, summary: str, details: str, t_dss: datetime
+    ) -> None:
+        """
+        Fail the passed sub check with the passed summary and details, and fail
+        the main check with the passed details.
+
+        The provided timestamp is forwarded into the query_timestamps of the check failure.
+        """
+        sub_check.record_failed(
+            summary=summary,
+            details=details,
+            query_timestamps=[t_dss],
+        )
+
+        self._main_check.record_failed(
+            summary=f"Invalid OIR returned by the DSS: {summary}",
+            details=details,
+            query_timestamps=[t_dss],
+        )
+
+    def _fail_with_schema_errors(
+        self,
+        check: PendingCheck,
+        errors: List[schema_validation.ValidationError],
+        t_dss: datetime,
+    ) -> None:
+        """Fail the passed check with the passed schema validation errors, and fail
+        the main check with the passed details."""
+        details = "\n".join(f"[{e.json_path}] {e.message}" for e in errors)
+        self._fail_sub_check(
+            check,
+            summary="Response format was invalid",
+            details="Found the following schema validation errors in the DSS response:\n"
+            + details,
+            t_dss=t_dss,
+        )
+
+    def _validate_oir(
+        self,
+        expected_entity_id: EntityID,
+        dss_oir: OperationalIntentReference,
+        t_dss: datetime,
+        previous_version: Optional[int],
+        expected_version: Optional[int],
+        previous_ovn: Optional[str],
+        expected_ovn: Optional[str],
+    ) -> None:
+        """
+        Args:
+            expected_entity_id: the ID we expect to find in the entity
+            dss_oir: the OIR returned by the DSS
+            t_dss: timestamp of the query to the DSS for failure reporting
+            previous_ovn: previous OVN of the entity, if we are verifying a mutation
+            expected_ovn: expected OVN of the entity, if we are verifying a read query
+            previous_version: previous version of the entity, if we are verifying a mutation
+            expected_version: expected version of the entity, if we are verifying a read query
+        """
+
+        with self._scenario.check(
+            "Returned operational intent reference ID is correct", self._pid
+        ) as check:
+            if dss_oir.id != expected_entity_id:
+                self._fail_sub_check(
+                    check,
+                    summary=f"Returned OIR ID is incorrect",
+                    details=f"Expected OIR ID {expected_entity_id}, got {dss_oir.id}",
+                    t_dss=t_dss,
+                )
+
+        with self._scenario.check(
+            "Returned operational intent reference has a manager", self._pid
+        ) as check:
+            # Check for empty string. None should have failed the schema check earlier
+            if not dss_oir.manager:
+                self._fail_sub_check(
+                    check,
+                    summary="No OIR manager was specified",
+                    details=f"Expected: {self._expected_manager}, got an empty or undefined string",
+                    t_dss=t_dss,
+                )
+
+        with self._scenario.check(
+            "Returned operational intent reference manager is correct", self._pid
+        ) as check:
+            if dss_oir.manager != self._expected_manager:
+                self._fail_sub_check(
+                    check,
+                    summary="Returned manager is incorrect",
+                    details=f"Expected. {self._expected_manager}, got {dss_oir.manager}",
+                    t_dss=t_dss,
+                )
+
+        with self._scenario.check(
+            "Returned operational intent reference has an USS base URL", self._pid
+        ) as check:
+            # If uss_base_url is not present, or it is None or Empty, we should fail:
+            if "uss_base_url" not in dss_oir or not dss_oir.uss_base_url:
+                self._fail_sub_check(
+                    check,
+                    summary="Returned OIR has no USS base URL",
+                    details="The OIR returned by the DSS has no USS base URL when it should have one",
+                    t_dss=t_dss,
+                )
+
+        with self._scenario.check(
+            "Returned operational intent reference base URL is correct", self._pid
+        ) as check:
+            if dss_oir.uss_base_url != self._oir_params.uss_base_url:
+                self._fail_sub_check(
+                    check,
+                    summary="Returned USS Base URL does not match provided one",
+                    details=f"Provided: {self._oir_params.uss_base_url}, Returned: {dss_oir.uss_base_url}",
+                    t_dss=t_dss,
+                )
+
+        with self._scenario.check(
+            "Returned operational intent reference has a start time", self._pid
+        ) as check:
+            if "time_start" not in dss_oir or dss_oir.time_start is None:
+                self._fail_sub_check(
+                    check,
+                    summary="Returned OIR has no start time",
+                    details="The operational intent reference returned by the DSS has no start time when it should have one",
+                    t_dss=t_dss,
+                )
+
+        with self._scenario.check(
+            "Returned operational intent reference has an end time", self._pid
+        ) as check:
+            if "time_end" not in dss_oir or dss_oir.time_end is None:
+                self._fail_sub_check(
+                    check,
+                    summary="Returned OIR has no end time",
+                    details="The operational intent reference returned by the DSS has no end time when it should have one",
+                    t_dss=t_dss,
+                )
+
+        with self._scenario.check("Returned start time is correct", self._pid) as check:
+            if (
+                abs(
+                    dss_oir.time_start.value.datetime - self._expected_start
+                ).total_seconds()
+                > TIME_TOLERANCE_SEC
+            ):
+                self._fail_sub_check(
+                    check,
+                    summary="Returned start time does not match provided one",
+                    details=f"Provided: {self._oir_params.start_time}, Returned: {dss_oir.time_start}",
+                    t_dss=t_dss,
+                )
+
+        with self._scenario.check("Returned end time is correct", self._pid) as check:
+            if (
+                abs(
+                    dss_oir.time_end.value.datetime - self._expected_end
+                ).total_seconds()
+                > TIME_TOLERANCE_SEC
+            ):
+                self._fail_sub_check(
+                    check,
+                    summary="Returned end time does not match provided one",
+                    details=f"Provided: {self._oir_params.end_time}, Returned: {dss_oir.time_end}",
+                    t_dss=t_dss,
+                )
+
+        # If the previous OVN is not None, we are dealing with a mutation:
+        if previous_ovn is not None:
+            with self._scenario.check(
+                "Mutated operational intent reference OVN is updated", self._pid
+            ) as check:
+                if dss_oir.ovn == previous_ovn:
+                    self._fail_sub_check(
+                        check,
+                        summary="Returned OIR OVN was not updated",
+                        details=f"Expected OVN to be different from {previous_ovn}, but it was not",
+                        t_dss=t_dss,
+                    )
+
+        if expected_ovn is not None:
+            with self._scenario.check(
+                "Non-mutated operational intent reference keeps the same OVN", self._pid
+            ) as check:
+                if dss_oir.ovn != expected_ovn:
+                    self._fail_sub_check(
+                        check,
+                        summary="Returned OIR OVN was updated",
+                        details=f"Expected OVN to be {expected_ovn}, Returned: {dss_oir.ovn}",
+                        t_dss=t_dss,
+                    )
+
+        # If the previous version is not None, we are dealing with a mutation:
+        if previous_version is not None:
+            with self._scenario.check(
+                "Mutated operational intent reference version is updated", self._pid
+            ) as check:
+                # TODO confirm that a mutation should imply a version update
+                if dss_oir.version == previous_version:
+                    self._fail_sub_check(
+                        check,
+                        summary="Returned OIR version was not updated",
+                        details=f"Expected version to be different from {previous_ovn}, but it was not",
+                        t_dss=t_dss,
+                    )
+
+        # TODO version _might_ get incremented due to changes caused outside of the uss_qualifier
+        #  and we should probably check if it is equal or higher.
+        if expected_version is not None:
+            with self._scenario.check(
+                "Non-mutated operational intent reference keeps the same version",
+                self._pid,
+            ) as check:
+                if dss_oir.version != expected_version:
+                    self._fail_sub_check(
+                        check,
+                        summary="Returned OIR version was updated",
+                        details=f"Expected version to be {expected_ovn}, Returned: {dss_oir.version}",
+                        t_dss=t_dss,
+                    )
+
+        # TODO add check for:
+        #  - state
+        #  - subscription ID of the OIR (based on passed parameters, if these were set)
+
+    def _validate_put_oir_response_schema(
+        self, oir_query: fetch.Query, t_dss: datetime, action: str
+    ):
+        """Validate response bodies for creation and mutation of OIRs."""
+
+        check_name = (
+            "Create operational intent reference response format conforms to spec"
+            if action == "create"
+            else "Mutate operational intent reference response format conforms to spec"
+        )
+
+        with self._scenario.check(check_name, self._pid) as check:
+            errors = schema_validation.validate(
+                F3548_21.OpenAPIPath,
+                F3548_21.ChangeOperationalIntentReferenceResponse,
+                oir_query.response.json,
+            )
+            if errors:
+                self._fail_with_schema_errors(check, errors, t_dss)
+
+    def validate_created_oir(
+        self, expected_oir_id: EntityID, new_oir: fetch.Query
+    ) -> None:
+        """Validate an OIR that was just explicitly created, meaning
+        we don't have a previous version to compare to, and we expect it to not be an implicit one."""
+
+        t_dss = new_oir.request.timestamp
+
+        # Validate the response schema
+        self._validate_put_oir_response_schema(new_oir, t_dss, "create")
+
+        # TODO do we want to add a wrapper type? We should check the schema before parsing?
+        #  Otherwise we run into exceptions before actually checking the schema?
+        # Expected to pass given that we validated the JSON against the schema
+        parsed_resp = ImplicitDict.parse(
+            new_oir.response.json, ChangeOperationalIntentReferenceResponse
+        )
+
+        oir: OperationalIntentReference = parsed_resp.operational_intent_reference
+
+        # Validate the OIR itself
+        self._validate_oir(
+            expected_entity_id=expected_oir_id,
+            dss_oir=oir,
+            t_dss=t_dss,
+            previous_version=None,
+            expected_version=None,
+            previous_ovn=None,
+            expected_ovn=None,
+        )
+
+    def validate_mutated_oir(
+        self,
+        expected_oir_id: EntityID,
+        mutated_oir: fetch.Query,
+        previous_ovn: str,
+        previous_version: int,
+    ) -> None:
+        """Validate an OIR that was just mutated, meaning we have a previous version and OVN to compare to.
+        Callers must specify if this is an implicit OIR or not."""
+        t_dss = mutated_oir.request.timestamp
+
+        # Validate the response schema
+        self._validate_put_oir_response_schema(mutated_oir, t_dss, "mutate")
+
+        oir = ImplicitDict.parse(
+            mutated_oir.response.json, ChangeOperationalIntentReferenceResponse
+        ).operational_intent_reference
+
+        # Validate the OIR itself
+        self._validate_oir(
+            expected_entity_id=expected_oir_id,
+            dss_oir=oir,
+            t_dss=t_dss,
+            previous_version=previous_version,
+            expected_version=None,
+            previous_ovn=previous_ovn,
+            expected_ovn=None,
+        )
+
+    def validate_fetched_oir(
+        self,
+        expected_oir_id: EntityID,
+        fetched_oir: fetch.Query,
+        expected_version: int,
+        expected_ovn: EntityOVN,
+    ) -> None:
+        """Validate an OIR that was directly queried by its ID."""
+
+        t_dss = fetched_oir.request.timestamp
+
+        # Validate the response schema
+        with self._scenario.check(
+            "Get operational intent reference response format conforms to spec",
+            self._pid,
+        ) as check:
+            errors = schema_validation.validate(
+                F3548_21.OpenAPIPath,
+                F3548_21.GetOperationalIntentReferenceResponse,
+                fetched_oir.response.json,
+            )
+            if errors:
+                self._fail_with_schema_errors(check, errors, t_dss)
+
+        parsed_resp = fetched_oir.parse_json_result(
+            GetOperationalIntentReferenceResponse
+        )
+        # Validate the OIR itself
+        self._validate_oir(
+            expected_entity_id=expected_oir_id,
+            dss_oir=parsed_resp.operational_intent_reference,
+            t_dss=t_dss,
+            previous_version=None,
+            expected_version=expected_version,
+            previous_ovn=None,
+            expected_ovn=expected_ovn,
+        )
+
+    def validate_searched_oir(
+        self,
+        expected_oir_id: EntityID,
+        search_response: fetch.Query,
+        expected_ovn: str,
+        expected_version: int,
+    ) -> None:
+        """Validate an OIR that was retrieved through search.
+        Note that the callers need to pass the entire response from the DSS, as the schema check
+        will be performed on the entire response, not just the OIR itself.
+        However, only the expected OIR is checked for the correctness of its contents."""
+
+        t_dss = search_response.request.timestamp
+
+        # Validate the response schema
+        self.validate_searched_oir_format(search_response, t_dss)
+
+        resp_parsed = search_response.parse_json_result(
+            QueryOperationalIntentReferenceResponse
+        )
+
+        by_id = {oir: oir.id for oir in resp_parsed.operational_intent_references}
+
+        with self._scenario.check(
+            "Created operational intent reference is in search results", self._pid
+        ) as check:
+            if expected_oir_id not in by_id:
+                self._fail_sub_check(
+                    check,
+                    summary="Created OIR is not present in search results",
+                    details=f"The OIR with ID {expected_oir_id} was expected to be found in the search results, but these only contained the following entities: {by_id.keys()}",
+                    t_dss=t_dss,
+                )
+                # Depending on the severity defined in the documentation, the above might not raise an exception,
+                # and we should still stop here if the check failed.
+                return
+
+        oir = by_id[expected_oir_id]
+
+        # Validate the OIR itself
+        self._validate_oir(
+            expected_entity_id=expected_oir_id,
+            dss_oir=oir,
+            t_dss=t_dss,
+            previous_ovn=None,
+            expected_ovn=expected_ovn,
+            previous_version=None,
+            expected_version=expected_version,
+        )
+
+    def validate_searched_oir_format(
+        self, search_response: fetch.Query, t_dss: datetime
+    ) -> None:
+        # Validate the response schema
+        with self._scenario.check(
+            "Search operational intent reference response format conforms to spec",
+            self._pid,
+        ) as check:
+            errors = schema_validation.validate(
+                F3548_21.OpenAPIPath,
+                F3548_21.QueryOperationalIntentReferenceResponse,
+                search_response.response.json,
+            )
+            if errors:
+                self._fail_with_schema_errors(check, errors, t_dss)
+
+    def validate_deleted_oir(
+        self,
+        expected_oir_id: EntityID,
+        deleted_oir: fetch.Query,
+        expected_ovn: str,
+        expected_version: int,
+    ) -> None:
+
+        t_dss = deleted_oir.request.timestamp
+
+        # Validate the response schema
+        with self._scenario.check(
+            "Delete operational intent reference response format conforms to spec",
+            self._pid,
+        ) as check:
+            errors = schema_validation.validate(
+                F3548_21.OpenAPIPath,
+                F3548_21.ChangeOperationalIntentReferenceResponse,
+                deleted_oir.response.json,
+            )
+            if errors:
+                self._fail_with_schema_errors(check, errors, t_dss)
+
+        oir_resp = deleted_oir.parse_json_result(
+            ChangeOperationalIntentReferenceResponse
+        )
+
+        # Validate the OIR itself
+        self._validate_oir(
+            expected_entity_id=expected_oir_id,
+            dss_oir=oir_resp.operational_intent_reference,
+            t_dss=t_dss,
+            previous_ovn=None,
+            expected_ovn=expected_ovn,
+            previous_version=None,
+            expected_version=expected_version,
+        )