diff --git a/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/__init__.py b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_argument_handling.py b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_argument_handling.py
new file mode 100644
index 000000000..727f62ff7
--- /dev/null
+++ b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_argument_handling.py
@@ -0,0 +1,230 @@
+"""Tests for whatsmyuri command argument handling.
+
+Validates that whatsmyuri accepts any BSON type as its argument value
+and ignores unrecognized fields.
+"""
+
+from datetime import datetime, timezone
+
+import pytest
+from bson import Binary, Code, Decimal128, Int64, MaxKey, MinKey, ObjectId, Regex, Timestamp
+
+from documentdb_tests.compatibility.tests.system.diagnostic.utils.diagnostic_test_case import (
+    DiagnosticTestCase,
+)
+from documentdb_tests.framework.assertions import assertProperties
+from documentdb_tests.framework.executor import execute_admin_command
+from documentdb_tests.framework.parametrize import pytest_params
+from documentdb_tests.framework.property_checks import Eq
+
+pytestmark = pytest.mark.admin
+
+
+# Property [Type Acceptance]: whatsmyuri accepts all BSON types as the command field value.
+ARGUMENT_TYPE_TESTS: list[DiagnosticTestCase] = [
+    DiagnosticTestCase(
+        "int_1",
+        command={"whatsmyuri": 1},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept int 1",
+    ),
+    DiagnosticTestCase(
+        "int_0",
+        command={"whatsmyuri": 0},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept int 0",
+    ),
+    DiagnosticTestCase(
+        "int_neg1",
+        command={"whatsmyuri": -1},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept int -1",
+    ),
+    DiagnosticTestCase(
+        "bool_true",
+        command={"whatsmyuri": True},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept true",
+    ),
+    DiagnosticTestCase(
+        "bool_false",
+        command={"whatsmyuri": False},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept false",
+    ),
+    DiagnosticTestCase(
+        "string",
+        command={"whatsmyuri": "hello"},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept string",
+    ),
+    DiagnosticTestCase(
+        "empty_string",
+        command={"whatsmyuri": ""},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept empty string",
+    ),
+    DiagnosticTestCase(
+        "null",
+        command={"whatsmyuri": None},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept null",
+    ),
+    DiagnosticTestCase(
+        "empty_object",
+        command={"whatsmyuri": {}},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept empty object",
+    ),
+    DiagnosticTestCase(
+        "nested_object",
+        command={"whatsmyuri": {"a": {"b": 1}}},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept nested object",
+    ),
+    DiagnosticTestCase(
+        "empty_array",
+        command={"whatsmyuri": []},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept empty array",
+    ),
+    DiagnosticTestCase(
+        "array_with_elements",
+        command={"whatsmyuri": [1, 2, 3]},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept array with elements",
+    ),
+    DiagnosticTestCase(
+        "double",
+        command={"whatsmyuri": 1.5},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept double",
+    ),
+    DiagnosticTestCase(
+        "negative_double",
+        command={"whatsmyuri": -1.5},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept negative double",
+    ),
+    DiagnosticTestCase(
+        "large_int",
+        command={"whatsmyuri": 999_999_999},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept large int",
+    ),
+    DiagnosticTestCase(
+        "int64",
+        command={"whatsmyuri": Int64(1)},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept int64",
+    ),
+    DiagnosticTestCase(
+        "decimal128",
+        command={"whatsmyuri": Decimal128("1")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept decimal128",
+    ),
+    DiagnosticTestCase(
+        "decimal128_nan",
+        command={"whatsmyuri": Decimal128("NaN")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept decimal128 NaN",
+    ),
+    DiagnosticTestCase(
+        "decimal128_infinity",
+        command={"whatsmyuri": Decimal128("Infinity")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept decimal128 Infinity",
+    ),
+    DiagnosticTestCase(
+        "decimal128_neg_zero",
+        command={"whatsmyuri": Decimal128("-0")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept decimal128 negative zero",
+    ),
+    DiagnosticTestCase(
+        "infinity",
+        command={"whatsmyuri": float("inf")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept infinity",
+    ),
+    DiagnosticTestCase(
+        "neg_infinity",
+        command={"whatsmyuri": float("-inf")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept negative infinity",
+    ),
+    DiagnosticTestCase(
+        "nan",
+        command={"whatsmyuri": float("nan")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept NaN",
+    ),
+    DiagnosticTestCase(
+        "date",
+        command={"whatsmyuri": datetime(2024, 1, 1, tzinfo=timezone.utc)},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept date",
+    ),
+    DiagnosticTestCase(
+        "binData",
+        command={"whatsmyuri": Binary(b"")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept binData",
+    ),
+    DiagnosticTestCase(
+        "objectId",
+        command={"whatsmyuri": ObjectId()},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept objectId",
+    ),
+    DiagnosticTestCase(
+        "regex",
+        command={"whatsmyuri": Regex("test")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept regex",
+    ),
+    DiagnosticTestCase(
+        "timestamp",
+        command={"whatsmyuri": Timestamp(0, 0)},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept timestamp",
+    ),
+    DiagnosticTestCase(
+        "minKey",
+        command={"whatsmyuri": MinKey()},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept minKey",
+    ),
+    DiagnosticTestCase(
+        "maxKey",
+        command={"whatsmyuri": MaxKey()},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept maxKey",
+    ),
+    DiagnosticTestCase(
+        "code",
+        command={"whatsmyuri": Code("function(){}")},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should accept JavaScript code",
+    ),
+]
+
+# Property [Extra Fields Ignored]: whatsmyuri ignores unrecognized fields.
+EXTRA_FIELD_TESTS: list[DiagnosticTestCase] = [
+    DiagnosticTestCase(
+        "extra_field_ignored",
+        command={"whatsmyuri": 1, "unknownField": 1},
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should succeed even with unrecognized fields",
+    ),
+]
+
+ALL_TESTS = ARGUMENT_TYPE_TESTS + EXTRA_FIELD_TESTS
+
+
+@pytest.mark.parametrize("test", pytest_params(ALL_TESTS))
+def test_whatsmyuri_argument_handling(collection, test):
+    """Test whatsmyuri argument handling."""
+    result = execute_admin_command(collection, test.command)
+    assertProperties(result, test.checks, msg=test.msg, raw_res=True)
diff --git a/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_consistency.py b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_consistency.py
new file mode 100644
index 000000000..f5dce61bc
--- /dev/null
+++ b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_consistency.py
@@ -0,0 +1,76 @@
+"""Tests for whatsmyuri command consistency and database independence.
+
+Validates that whatsmyuri returns consistent results across calls,
+databases, and is unaffected by server settings.
+"""
+
+import pytest
+
+from documentdb_tests.compatibility.tests.system.diagnostic.utils.diagnostic_test_case import (
+    DiagnosticTestCase,
+)
+from documentdb_tests.framework.assertions import (
+    assertProperties,
+    assertSuccess,
+    assertSuccessPartial,
+)
+from documentdb_tests.framework.executor import execute_admin_command, execute_command
+from documentdb_tests.framework.parametrize import pytest_params
+from documentdb_tests.framework.property_checks import Eq
+
+pytestmark = pytest.mark.admin
+
+
+# Property [Database Independence]: whatsmyuri succeeds on any database.
+DATABASE_INDEPENDENCE_TESTS: list[DiagnosticTestCase] = [
+    DiagnosticTestCase(
+        "any_database",
+        command={"whatsmyuri": 1},
+        use_admin=False,
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should succeed on non-admin database",
+    ),
+]
+
+
+@pytest.mark.parametrize("test", pytest_params(DATABASE_INDEPENDENCE_TESTS))
+def test_whatsmyuri_consistency(collection, test):
+    """Test whatsmyuri consistency."""
+    result = execute_command(collection, test.command)
+    assertProperties(result, test.checks, msg=test.msg, raw_res=True)
+
+
+def test_whatsmyuri_idempotent(collection):
+    """Test whatsmyuri idempotency."""
+    result1 = execute_admin_command(collection, {"whatsmyuri": 1})
+    result2 = execute_admin_command(collection, {"whatsmyuri": 1})
+    assertSuccess(
+        result2,
+        expected=result1,
+        msg="whatsmyuri should return identical results across calls",
+        raw_res=True,
+    )
+
+
+def test_whatsmyuri_same_result_any_database(collection):
+    """Test whatsmyuri returns same result from admin and non-admin database."""
+    admin_result = execute_admin_command(collection, {"whatsmyuri": 1})
+    db_result = execute_command(collection, {"whatsmyuri": 1})
+    assertSuccess(
+        db_result,
+        expected=admin_result,
+        msg="whatsmyuri should return same result from any database",
+        raw_res=True,
+    )
+
+
+def test_whatsmyuri_nonexistent_database(collection):
+    """Test whatsmyuri on a non-existent database."""
+    other_db = f"{collection.name}_nonexistent_db"
+    other_col = collection.database.client[other_db][collection.name]
+    result = execute_command(other_col, {"whatsmyuri": 1})
+    assertSuccessPartial(
+        result,
+        {"ok": 1.0},
+        msg="whatsmyuri should succeed on non-existent database",
+    )
diff --git a/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_error_conditions.py b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_error_conditions.py
new file mode 100644
index 000000000..1d22a4dee
--- /dev/null
+++ b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_error_conditions.py
@@ -0,0 +1,68 @@
+"""Tests for whatsmyuri command error conditions.
+
+Validates that invalid usages of whatsmyuri produce appropriate errors.
+Uses CommandTestCase because the aggregation stage test needs ctx.collection
+for the aggregate command.
+"""
+
+import pytest
+
+from documentdb_tests.compatibility.tests.core.utils.command_test_case import (
+    CommandContext,
+    CommandTestCase,
+)
+from documentdb_tests.framework.assertions import assertResult
+from documentdb_tests.framework.error_codes import (
+    COMMAND_NOT_FOUND_ERROR,
+    UNKNOWN_PIPELINE_STAGE_ERROR,
+)
+from documentdb_tests.framework.executor import execute_admin_command, execute_command
+from documentdb_tests.framework.parametrize import pytest_params
+
+pytestmark = pytest.mark.admin
+
+
+# Property [Case Sensitivity]: whatsmyuri is case-sensitive and rejects mismatched casing.
+CASE_SENSITIVITY_TESTS: list[CommandTestCase] = [
+    CommandTestCase(
+        "case_sensitive_capital_w",
+        command={"WhatsMyUri": 1},
+        error_code=COMMAND_NOT_FOUND_ERROR,
+        msg="whatsmyuri should reject camel-cased command name",
+    ),
+    CommandTestCase(
+        "case_sensitive_all_upper",
+        command={"WHATSMYURI": 1},
+        error_code=COMMAND_NOT_FOUND_ERROR,
+        msg="whatsmyuri should reject all-uppercase command name",
+    ),
+]
+
+# Property [Not a Pipeline Stage]: whatsmyuri is not usable as an aggregation stage.
+PIPELINE_STAGE_TESTS: list[CommandTestCase] = [
+    CommandTestCase(
+        "as_aggregation_stage",
+        command=lambda ctx: {
+            "aggregate": ctx.collection,
+            "pipeline": [{"$whatsmyuri": {}}],
+            "cursor": {},
+        },
+        error_code=UNKNOWN_PIPELINE_STAGE_ERROR,
+        msg="whatsmyuri should not be usable as an aggregation stage",
+    ),
+]
+
+ALL_TESTS = CASE_SENSITIVITY_TESTS + PIPELINE_STAGE_TESTS
+
+
+@pytest.mark.parametrize("test", pytest_params(ALL_TESTS))
+def test_whatsmyuri_error_conditions(collection, test):
+    """Test whatsmyuri error conditions."""
+    ctx = CommandContext.from_collection(collection)
+    cmd = test.build_command(ctx)
+    # Case sensitivity tests target the admin db; the aggregate test does not.
+    if next(iter(cmd)).lower() == "whatsmyuri":
+        result = execute_admin_command(collection, cmd)
+    else:
+        result = execute_command(collection, cmd)
+    assertResult(result, error_code=test.error_code, msg=test.msg)
diff --git a/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_response_structure.py b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_response_structure.py
new file mode 100644
index 000000000..0e754ac17
--- /dev/null
+++ b/documentdb_tests/compatibility/tests/system/diagnostic/commands/whatsmyuri/test_whatsmyuri_response_structure.py
@@ -0,0 +1,75 @@
+"""Tests for whatsmyuri command response structure.
+
+Validates presence, types, and values of response fields returned
+by whatsmyuri. The response contains a 'you' field with the client's
+connection URI (ip:port) and the standard 'ok' field.
+"""
+
+import pytest
+
+from documentdb_tests.compatibility.tests.system.diagnostic.utils.diagnostic_test_case import (
+    DiagnosticTestCase,
+)
+from documentdb_tests.framework.assertions import assertProperties
+from documentdb_tests.framework.executor import execute_admin_command
+from documentdb_tests.framework.parametrize import pytest_params
+from documentdb_tests.framework.property_checks import Eq, Exists, IsType, NonEmptyStr
+
+pytestmark = pytest.mark.admin
+
+
+# Property [Response Structure]: whatsmyuri returns ok and a non-empty you field.
+PROPERTY_TESTS: list[DiagnosticTestCase] = [
+    DiagnosticTestCase(
+        id="ok_is_1",
+        checks={"ok": Eq(1.0)},
+        msg="whatsmyuri should return ok equal to 1.0",
+    ),
+    DiagnosticTestCase(
+        id="ok_is_double",
+        checks={"ok": IsType("double")},
+        msg="whatsmyuri should return ok as a double",
+    ),
+    DiagnosticTestCase(
+        id="you_exists",
+        checks={"you": Exists()},
+        msg="whatsmyuri should return a you field",
+    ),
+    DiagnosticTestCase(
+        id="you_is_string",
+        checks={"you": IsType("string")},
+        msg="whatsmyuri should return you as a string",
+    ),
+    DiagnosticTestCase(
+        id="you_is_non_empty",
+        checks={"you": NonEmptyStr()},
+        msg="whatsmyuri should return a non-empty you field containing the client URI",
+    ),
+]
+
+
+@pytest.mark.parametrize("test", pytest_params(PROPERTY_TESTS))
+def test_whatsmyuri_response_properties(collection, test):
+    """Test whatsmyuri response structure."""
+    result = execute_admin_command(collection, {"whatsmyuri": 1})
+    assertProperties(result, test.checks, msg=test.msg, raw_res=True)
+
+
+# Property [URI Format]: the you field contains an ip:port pair with a colon separator.
+def test_whatsmyuri_you_contains_colon(collection):
+    """Test whatsmyuri you field contains ip:port separator."""
+    result = execute_admin_command(collection, {"whatsmyuri": 1})
+    you = result["you"]
+    if ":" not in you:
+        raise AssertionError(f"whatsmyuri you field should contain ':' (ip:port), got {you!r}")
+
+
+def test_whatsmyuri_you_port_is_numeric(collection):
+    """Test whatsmyuri you field has a numeric port."""
+    result = execute_admin_command(collection, {"whatsmyuri": 1})
+    you = result["you"]
+    port = you.rsplit(":", 1)[-1]
+    if not port.isdigit():
+        raise AssertionError(
+            f"whatsmyuri you field should have a numeric port after ':', got {you!r}"
+        )