feat: add step cutoff and mid-session export support

- max_step_index slices decisions in all 4 export formats
- Only set exported=True when session is completed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/api/endpoints/sessions.py

@@ -314,9 +314,10 @@ async def export_session(
         from app.services.variable_service import resolve_variables
         content = resolve_variables(content, session_vars)
 
-    # Mark as exported
-    session.exported = True
-    await db.commit()
+    # Only mark as exported if session is completed
+    if session.completed_at:
+        session.exported = True
+        await db.commit()
 
     return PlainTextResponse(content=content, media_type=media_type)
 

backend/app/services/export_service.py

@@ -150,7 +150,11 @@ def generate_markdown_export(session: Session, options: SessionExport) -> str:
     lines.append("## Troubleshooting Steps")
     lines.append("")
 
-    for i, decision in enumerate(session.decisions, 1):
+    decisions = session.decisions
+    if options.max_step_index is not None:
+        decisions = decisions[:options.max_step_index]
+
+    for i, decision in enumerate(decisions, 1):
         question = decision.get("question") or decision.get("action_performed", "Step")
         answer = decision.get("answer", "")
         notes = decision.get("notes", "")
@@ -233,7 +237,11 @@ def generate_text_export(session: Session, options: SessionExport) -> str:
     lines.append("TROUBLESHOOTING STEPS")
     lines.append("-" * 20)
 
-    for i, decision in enumerate(session.decisions, 1):
+    decisions = session.decisions
+    if options.max_step_index is not None:
+        decisions = decisions[:options.max_step_index]
+
+    for i, decision in enumerate(decisions, 1):
         question = decision.get("question") or decision.get("action_performed", "Step")
         answer = decision.get("answer", "")
         notes = decision.get("notes", "")
@@ -320,7 +328,11 @@ def generate_html_export(session: Session, options: SessionExport) -> str:
 
     html_parts.append('<h2>Troubleshooting Steps</h2>')
 
-    for i, decision in enumerate(session.decisions, 1):
+    decisions = session.decisions
+    if options.max_step_index is not None:
+        decisions = decisions[:options.max_step_index]
+
+    for i, decision in enumerate(decisions, 1):
         question = html.escape(decision.get("question") or decision.get("action_performed", "Step"))
         answer = html.escape(decision.get("answer", ""))
         notes = html.escape(decision.get("notes", ""))
@@ -388,8 +400,11 @@ def generate_psa_export(session: Session, options: SessionExport) -> str:
 
     # Steps taken
     lines.append("--- STEPS TAKEN ---")
-    if session.decisions:
-        for i, decision in enumerate(session.decisions, 1):
+    decisions = session.decisions
+    if options.max_step_index is not None:
+        decisions = decisions[:options.max_step_index]
+    if decisions:
+        for i, decision in enumerate(decisions, 1):
             question = decision.get("question") or decision.get("action_performed", "Step")
             answer = decision.get("answer", "")
             notes = decision.get("notes", "")

backend/tests/test_sessions.py

@@ -1184,3 +1184,138 @@ class TestSessions:
         content = response.text
         assert "## Resolution" not in content
         assert "Should not appear" not in content
+
+    @pytest.mark.asyncio
+    async def test_export_max_step_index(
+        self, client: AsyncClient, auth_headers: dict, test_tree: dict
+    ):
+        """Test max_step_index limits exported steps."""
+        create_response = await client.post(
+            "/api/v1/sessions",
+            json={"tree_id": test_tree["id"]},
+            headers=auth_headers
+        )
+        session_id = create_response.json()["id"]
+
+        decisions = [
+            {"node_id": "n1", "question": "Step one?", "answer": "Yes", "timestamp": "2026-02-13T10:00:00Z", "attachments": []},
+            {"node_id": "n2", "question": "Step two?", "answer": "No", "timestamp": "2026-02-13T10:01:00Z", "attachments": []},
+            {"node_id": "n3", "question": "Step three?", "answer": "Maybe", "timestamp": "2026-02-13T10:02:00Z", "attachments": []},
+        ]
+        await client.put(
+            f"/api/v1/sessions/{session_id}",
+            json={"decisions": decisions},
+            headers=auth_headers
+        )
+
+        response = await client.post(
+            f"/api/v1/sessions/{session_id}/export",
+            json={"format": "markdown", "max_step_index": 2},
+            headers=auth_headers
+        )
+        content = response.text
+        assert "Step one?" in content
+        assert "Step two?" in content
+        assert "Step three?" not in content
+
+    @pytest.mark.asyncio
+    async def test_export_max_step_index_exceeds_count(
+        self, client: AsyncClient, auth_headers: dict, test_tree: dict
+    ):
+        """Test max_step_index larger than decision count returns all steps."""
+        create_response = await client.post(
+            "/api/v1/sessions",
+            json={"tree_id": test_tree["id"]},
+            headers=auth_headers
+        )
+        session_id = create_response.json()["id"]
+
+        decisions = [
+            {"node_id": "n1", "question": "Only step", "answer": "Done", "timestamp": "2026-02-13T10:00:00Z", "attachments": []},
+        ]
+        await client.put(
+            f"/api/v1/sessions/{session_id}",
+            json={"decisions": decisions},
+            headers=auth_headers
+        )
+
+        response = await client.post(
+            f"/api/v1/sessions/{session_id}/export",
+            json={"format": "markdown", "max_step_index": 100},
+            headers=auth_headers
+        )
+        assert response.status_code == 200
+        assert "Only step" in response.text
+
+    @pytest.mark.asyncio
+    async def test_export_max_step_index_zero_returns_422(
+        self, client: AsyncClient, auth_headers: dict, test_tree: dict
+    ):
+        """Test max_step_index=0 returns validation error."""
+        create_response = await client.post(
+            "/api/v1/sessions",
+            json={"tree_id": test_tree["id"]},
+            headers=auth_headers
+        )
+        session_id = create_response.json()["id"]
+
+        response = await client.post(
+            f"/api/v1/sessions/{session_id}/export",
+            json={"format": "markdown", "max_step_index": 0},
+            headers=auth_headers
+        )
+        assert response.status_code == 422
+
+    @pytest.mark.asyncio
+    async def test_export_in_progress_session_does_not_mark_exported(
+        self, client: AsyncClient, auth_headers: dict, test_tree: dict
+    ):
+        """Test that exporting an in-progress session does NOT set exported=True."""
+        create_response = await client.post(
+            "/api/v1/sessions",
+            json={"tree_id": test_tree["id"]},
+            headers=auth_headers
+        )
+        session_id = create_response.json()["id"]
+
+        await client.post(
+            f"/api/v1/sessions/{session_id}/export",
+            json={"format": "markdown"},
+            headers=auth_headers
+        )
+
+        response = await client.get(
+            f"/api/v1/sessions/{session_id}",
+            headers=auth_headers
+        )
+        assert response.json()["exported"] is False
+
+    @pytest.mark.asyncio
+    async def test_export_completed_session_marks_exported(
+        self, client: AsyncClient, auth_headers: dict, test_tree: dict
+    ):
+        """Test that exporting a completed session sets exported=True."""
+        create_response = await client.post(
+            "/api/v1/sessions",
+            json={"tree_id": test_tree["id"]},
+            headers=auth_headers
+        )
+        session_id = create_response.json()["id"]
+
+        await client.post(
+            f"/api/v1/sessions/{session_id}/complete",
+            json={"outcome": "resolved"},
+            headers=auth_headers
+        )
+
+        await client.post(
+            f"/api/v1/sessions/{session_id}/export",
+            json={"format": "markdown"},
+            headers=auth_headers
+        )
+
+        response = await client.get(
+            f"/api/v1/sessions/{session_id}",
+            headers=auth_headers
+        )
+        assert response.json()["exported"] is True