diff --git a/agent.codefly.yaml b/agent.codefly.yaml
index 30e5f9b..35cb26c 100644
--- a/agent.codefly.yaml
+++ b/agent.codefly.yaml
@@ -5,3 +5,6 @@ version: 0.0.63
 release:
   owner: workflow
   workflow: releaser.yml
+conformance:
+  mode: attach-existing-source
+  fixture: testdata/conformance
diff --git a/conformance_test.go b/conformance_test.go
new file mode 100644
index 0000000..9dedd9b
--- /dev/null
+++ b/conformance_test.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+
+	"github.com/codefly-dev/core/resources"
+	"github.com/stretchr/testify/require"
+	"gopkg.in/yaml.v3"
+)
+
+func TestConformanceUsesExistingPythonSource(t *testing.T) {
+	data, err := os.ReadFile("agent.codefly.yaml")
+	require.NoError(t, err)
+	var manifest struct {
+		Conformance struct {
+			Mode    string `yaml:"mode"`
+			Fixture string `yaml:"fixture"`
+		} `yaml:"conformance"`
+	}
+	require.NoError(t, yaml.Unmarshal(data, &manifest))
+	require.Equal(t, "attach-existing-source", manifest.Conformance.Mode)
+	require.True(t, filepath.IsLocal(manifest.Conformance.Fixture))
+	workspace, err := resources.LoadWorkspaceFromDir(t.Context(), manifest.Conformance.Fixture)
+	require.NoError(t, err)
+	module, err := workspace.RootModule(t.Context())
+	require.NoError(t, err)
+	service, err := module.LoadServiceFromName(t.Context(), "subject")
+	require.NoError(t, err)
+	require.Equal(t, "codefly.dev", service.Agent.Publisher)
+	require.Equal(t, "python", service.Agent.Name)
+	require.Equal(t, "latest", service.Agent.Version, "the isolated release gate must exercise its candidate")
+	command := exec.CommandContext(t.Context(), "uv", "run", "--frozen", "python", "-m", "unittest", "discover")
+	command.Dir = filepath.Join(manifest.Conformance.Fixture, "services", "subject", "code")
+	command.Env = append(os.Environ(), "UV_PROJECT_ENVIRONMENT="+filepath.Join(t.TempDir(), "venv"), "PYTHONDONTWRITEBYTECODE=1")
+	output, err := command.CombinedOutput()
+	require.NoError(t, err, string(output))
+	require.Contains(t, string(output), "Ran 1 test")
+}
diff --git a/go.mod b/go.mod
index d75bb42..a644659 100644
--- a/go.mod
+++ b/go.mod
@@ -5,6 +5,7 @@ go 1.27.0
 require (
 	github.com/codefly-dev/core v0.4.0
 	github.com/scagogogo/python-requirements-parser v0.0.0-20250717025652-6ca77234c827
+	github.com/stretchr/testify v1.12.1
 	gopkg.in/yaml.v3 v3.0.1
 )
 
diff --git a/go.sum b/go.sum
index 211cb2b..b9fa985 100644
--- a/go.sum
+++ b/go.sum
@@ -250,8 +250,8 @@ github.com/sirupsen/logrus v1.9.4/go.mod h1:ftWc9WdOfJ0a92nsE2jF5u5ZwH8Bv2zdeOC4
 github.com/skeema/knownhosts v1.3.2 h1:EDL9mgf4NzwMXCTfaxSD/o/a5fxDw/xL9nkU28JjdBg=
 github.com/skeema/knownhosts v1.3.2/go.mod h1:bEg3iQAuw+jyiw+484wwFJoKSLwcfd7fqRy+N0QTiow=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.5.2 h1:xuMeJ0Sdp5ZMRXx/aWO6RZxdr3beISkG5/G/aIRr3pY=
-github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
+github.com/stretchr/objx v0.5.3 h1:jmXUvGomnU1o3W/V5h2VEradbpJDwGrzugQQvL0POH4=
+github.com/stretchr/objx v0.5.3/go.mod h1:rDQraq+vQZU7Fde9LOZLr8Tax6zZvy4kuNKF+QYS+U0=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
diff --git a/testdata/conformance/services/subject/code/.python-version b/testdata/conformance/services/subject/code/.python-version
new file mode 100644
index 0000000..e4fba21
--- /dev/null
+++ b/testdata/conformance/services/subject/code/.python-version
@@ -0,0 +1 @@
+3.12
diff --git a/testdata/conformance/services/subject/code/pyproject.toml b/testdata/conformance/services/subject/code/pyproject.toml
new file mode 100644
index 0000000..ba68352
--- /dev/null
+++ b/testdata/conformance/services/subject/code/pyproject.toml
@@ -0,0 +1,5 @@
+[project]
+name = "python-conformance"
+version = "0.0.0"
+requires-python = ">=3.12"
+dependencies = []
diff --git a/testdata/conformance/services/subject/code/test_calculation.py b/testdata/conformance/services/subject/code/test_calculation.py
new file mode 100644
index 0000000..f190eb4
--- /dev/null
+++ b/testdata/conformance/services/subject/code/test_calculation.py
@@ -0,0 +1,6 @@
+import unittest
+
+
+class CalculationTests(unittest.TestCase):
+    def test_calculation(self):
+        self.assertEqual(sum([1, 2, 3]), 6)
diff --git a/testdata/conformance/services/subject/code/uv.lock b/testdata/conformance/services/subject/code/uv.lock
new file mode 100644
index 0000000..ebabd62
--- /dev/null
+++ b/testdata/conformance/services/subject/code/uv.lock
@@ -0,0 +1,8 @@
+version = 1
+revision = 3
+requires-python = ">=3.12"
+
+[[package]]
+name = "python-conformance"
+version = "0.0.0"
+source = { virtual = "." }
diff --git a/testdata/conformance/services/subject/service.codefly.yaml b/testdata/conformance/services/subject/service.codefly.yaml
new file mode 100644
index 0000000..6737fff
--- /dev/null
+++ b/testdata/conformance/services/subject/service.codefly.yaml
@@ -0,0 +1,9 @@
+name: subject
+version: 0.0.0
+agent:
+  kind: codefly:service
+  publisher: codefly.dev
+  name: python
+  version: latest
+spec:
+  source-dir: code
diff --git a/testdata/conformance/workspace.codefly.yaml b/testdata/conformance/workspace.codefly.yaml
new file mode 100644
index 0000000..e814c85
--- /dev/null
+++ b/testdata/conformance/workspace.codefly.yaml
@@ -0,0 +1,4 @@
+name: python-conformance
+layout: flat
+services:
+  - name: subject