test: add prompt building, routing, and JSON parsing tests

28 tests covering parse_mentions, route_by_keywords,
parse_orchestrator_response, build_orchestrator_system_prompt,
and build_chat_messages.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_prompts.py

@@ -0,0 +1,181 @@
+"""Tests for agents/prompts.py — prompt building, routing, parsing."""
+
+from agents.prompts import (
+    parse_mentions,
+    route_by_keywords,
+    parse_orchestrator_response,
+    build_orchestrator_system_prompt,
+    build_chat_messages,
+    CAD_TRIGGER_KEYWORDS,
+)
+
+
+class TestParseMentions:
+    def test_no_mentions(self):
+        cleaned, mentions = parse_mentions("I need a bracket")
+        assert cleaned == "I need a bracket"
+        assert mentions == []
+
+    def test_single_mention(self):
+        cleaned, mentions = parse_mentions("@design what shape?")
+        assert "design" in mentions
+        assert "@design" not in cleaned
+
+    def test_multiple_mentions(self):
+        cleaned, mentions = parse_mentions("@design @engineering check this")
+        assert "design" in mentions
+        assert "engineering" in mentions
+        assert "@design" not in cleaned
+        assert "@engineering" not in cleaned
+
+    def test_cad_mention(self):
+        cleaned, mentions = parse_mentions("@cad generate a preview")
+        assert "cad" in mentions
+
+    def test_case_insensitive(self):
+        cleaned, mentions = parse_mentions("@Design what do you think?")
+        assert "design" in mentions
+
+    def test_mention_mid_sentence(self):
+        cleaned, mentions = parse_mentions("Can @engineering check the wall thickness?")
+        assert "engineering" in mentions
+        assert "Can" in cleaned
+        assert "check the wall thickness?" in cleaned
+
+
+class TestRouteByKeywords:
+    def test_design_keywords(self):
+        agents = route_by_keywords("I want a sleek design with smooth shape")
+        assert "design" in agents
+
+    def test_engineering_keywords(self):
+        agents = route_by_keywords("Use M6 bolts with 3mm wall thickness in aluminum")
+        assert "engineering" in agents
+
+    def test_cnc_keywords(self):
+        agents = route_by_keywords("Can this be machined on a 3-axis CNC mill?")
+        assert "cnc" in agents
+
+    def test_cad_trigger(self):
+        agents = route_by_keywords("Generate a preview of the part")
+        assert "cad" in agents
+
+    def test_default_when_no_match(self):
+        agents = route_by_keywords("hello there")
+        assert agents == ["design", "engineering"]
+
+    def test_max_three_agents(self):
+        agents = route_by_keywords(
+            "design shape in aluminum for CNC machining, generate preview"
+        )
+        assert len(agents) <= 3
+
+    def test_sorted_by_relevance(self):
+        agents = route_by_keywords("M4 M6 tolerance clearance aluminum steel wall")
+        assert agents[0] == "engineering"
+
+
+class TestParseOrchestratorResponse:
+    def test_valid_json(self):
+        resp = '{"agents": [{"id": "design", "message": "Nice bracket."}]}'
+        parsed = parse_orchestrator_response(resp)
+        assert len(parsed) == 1
+        assert parsed[0]["id"] == "design"
+        assert parsed[0]["message"] == "Nice bracket."
+        assert parsed[0]["code"] is None
+
+    def test_json_with_code(self):
+        resp = '{"agents": [{"id": "cad", "message": "Done.", "code": "result = cq.Workplane().box(10,10,10)"}]}'
+        parsed = parse_orchestrator_response(resp)
+        assert parsed[0]["code"] == "result = cq.Workplane().box(10,10,10)"
+
+    def test_json_in_markdown_fence(self):
+        resp = '```json\n{"agents": [{"id": "engineering", "message": "Use 3mm walls."}]}\n```'
+        parsed = parse_orchestrator_response(resp)
+        assert len(parsed) == 1
+        assert parsed[0]["id"] == "engineering"
+
+    def test_multiple_agents(self):
+        resp = '{"agents": [{"id": "design", "message": "A"}, {"id": "cnc", "message": "B"}]}'
+        parsed = parse_orchestrator_response(resp)
+        assert len(parsed) == 2
+        assert parsed[0]["id"] == "design"
+        assert parsed[1]["id"] == "cnc"
+
+    def test_invalid_json_fallback(self):
+        resp = "I think you should use aluminum."
+        parsed = parse_orchestrator_response(resp)
+        assert len(parsed) == 1
+        assert parsed[0]["id"] == "design"
+        assert parsed[0]["message"] == resp
+
+    def test_empty_agents_fallback(self):
+        resp = '{"agents": []}'
+        parsed = parse_orchestrator_response(resp)
+        assert len(parsed) == 1
+        assert parsed[0]["id"] == "design"
+
+    def test_missing_fields_skipped(self):
+        resp = '{"agents": [{"id": "design"}, {"id": "cnc", "message": "OK"}]}'
+        parsed = parse_orchestrator_response(resp)
+        assert len(parsed) == 1
+        assert parsed[0]["id"] == "cnc"
+
+
+class TestBuildOrchestratorSystemPrompt:
+    def test_default_agents(self):
+        prompt = build_orchestrator_system_prompt()
+        assert "Design Agent" in prompt
+        assert "Engineering Agent" in prompt
+        assert "CNC Agent" in prompt
+        assert '### CAD Coder' not in prompt  # persona block excluded
+
+    def test_specific_agents(self):
+        prompt = build_orchestrator_system_prompt(active_agents=["cad"])
+        assert "CAD Coder" in prompt
+        assert "Design Agent" not in prompt
+
+    def test_includes_json_format(self):
+        prompt = build_orchestrator_system_prompt()
+        assert '"agents"' in prompt
+        assert "JSON" in prompt
+
+    def test_cad_context_included(self):
+        prompt = build_orchestrator_system_prompt(
+            active_agents=["cad"], include_cad_context=True
+        )
+        assert "CadQuery" in prompt
+
+
+class TestBuildChatMessages:
+    def test_returns_system_and_user(self):
+        msgs = build_chat_messages("hello", [], "You are a bot.")
+        assert len(msgs) == 2
+        assert msgs[0]["role"] == "system"
+        assert msgs[0]["content"] == "You are a bot."
+        assert msgs[1]["role"] == "user"
+
+    def test_history_included_in_user_message(self, sample_history):
+        msgs = build_chat_messages("new msg", sample_history, "system prompt")
+        user_content = msgs[1]["content"]
+        assert "servo bracket" in user_content
+        assert "new msg" in user_content
+
+    def test_design_state_included(self):
+        msgs = build_chat_messages(
+            "make it wider", [], "system prompt",
+            design_state_text="Part: bracket\nMaterial: aluminum"
+        )
+        user_content = msgs[1]["content"]
+        assert "bracket" in user_content
+        assert "aluminum" in user_content
+
+    def test_history_truncation(self):
+        long_history = [
+            {"role": "user", "content": f"msg {i}"}
+            for i in range(50)
+        ]
+        msgs = build_chat_messages("latest", long_history, "sys", max_history=5)
+        user_content = msgs[1]["content"]
+        assert "msg 49" in user_content
+        assert "msg 0" not in user_content