diff --git a/.changeset/major-bats-refuse.md b/.changeset/major-bats-refuse.md
new file mode 100644
index 00000000..611d228e
--- /dev/null
+++ b/.changeset/major-bats-refuse.md
@@ -0,0 +1,5 @@
+---
+"apollo": patch
+---
+
+add langfuse tag for job code generation
diff --git a/services/job_chat/job_chat.py b/services/job_chat/job_chat.py
index 6e8d111b..288dabcf 100644
--- a/services/job_chat/job_chat.py
+++ b/services/job_chat/job_chat.py
@@ -668,6 +668,11 @@ def main(data_dict: dict) -> dict:
                 current_page=current_page
             )
 
+            # Tag the trace when code was generated, so we can filter for it.
+            if tracking and result.suggested_code:
+                with propagate_attributes(tags=["has_code_attachment"]):
+                    pass
+
             response_dict = {
                 "response": result.response,
                 "suggested_code": result.suggested_code,
diff --git a/services/job_chat/tests/unit/test_has_code_tag.py b/services/job_chat/tests/unit/test_has_code_tag.py
new file mode 100644
index 00000000..2113497c
--- /dev/null
+++ b/services/job_chat/tests/unit/test_has_code_tag.py
@@ -0,0 +1,68 @@
+"""Unit test for the `has_code_attachment` Langfuse tag (no LLM, no keys).
+
+job_chat.main() should tag the trace with `has_code_attachment` ONLY when the
+model actually produced code edits (result.suggested_code is truthy) AND
+tracking is on. We mock the LLM seam (AnthropicClient.generate) and spy on
+propagate_attributes to capture the tags it is called with.
+"""
+
+from contextlib import contextmanager
+from unittest.mock import MagicMock, patch
+
+from job_chat.job_chat import ChatResponse, main
+
+
+def _fake_response(suggested_code):
+    return ChatResponse(
+        response="ok",
+        suggested_code=suggested_code,
+        history=[],
+        usage={},
+        rag={},
+        diff=None,
+    )
+
+
+def _payload(metrics_opt_in=True):
+    return {
+        "content": "add error handling",
+        "context": {"expression": "get('x');", "adaptor": "@openfn/language-http@6.5.1"},
+        "suggest_code": True,
+        "metrics_opt_in": metrics_opt_in,
+        "meta": {"session_id": "s1", "user": {"id": "u1", "persona": "core-contributor"}},
+    }
+
+
+def _run_capturing_tags(suggested_code, metrics_opt_in=True):
+    """Run main() with mocked seams; return every `tags` value passed to propagate_attributes."""
+    captured = []
+
+    @contextmanager
+    def fake_propagate(**kwargs):
+        captured.append(kwargs.get("tags"))
+        yield
+
+    fake_client = MagicMock()
+    fake_client.generate.return_value = _fake_response(suggested_code)
+
+    with patch("job_chat.job_chat.propagate_attributes", side_effect=fake_propagate), \
+         patch("job_chat.job_chat.AnthropicClient", return_value=fake_client), \
+         patch("job_chat.job_chat.get_langfuse_client", return_value=MagicMock()):
+        main(_payload(metrics_opt_in=metrics_opt_in))
+
+    return captured
+
+
+def test_tag_applied_when_code_generated():
+    captured = _run_capturing_tags(suggested_code="newCode();")
+    assert ["has_code_attachment"] in captured
+
+
+def test_tag_absent_when_no_code():
+    captured = _run_capturing_tags(suggested_code=None)
+    assert ["has_code_attachment"] not in captured
+
+
+def test_tag_absent_when_not_tracking():
+    captured = _run_capturing_tags(suggested_code="newCode();", metrics_opt_in=False)
+    assert ["has_code_attachment"] not in captured