feat(weave): add provider name to turns

AGENTS.md

@@ -425,6 +425,9 @@ pnpm exec tsx examples/claudeAgents.ts
 - `Turn.messages` stores input messages, while `Turn.output_messages` stores
   the terminal agent response. `Turn.record(messages=..., output_messages=...)`
   replaces the two lists independently.
+- `Turn.provider_name` is the typed source for `gen_ai.provider.name` on the
+  root `invoke_agent` span. Pass it through `start_turn`, `Turn.record`, or
+  `log_turn` instead of setting that semantic attribute with `set_attributes`.
 - Keep streaming and batch paths aligned: `Turn._build_attrs()` must apply
   content gating and PII redaction to both lists before passing them to
   `invoke_agent_attributes()`, and `log_turn()` must accept both fields.
@@ -512,9 +515,9 @@ If there is something that doesn't make sense architecturally, devex-wise, or pr
 Think of this as the reverse-task assignment - a place where you can communicate back to us.
 
 - [ ] Add TypeScript testing guidelines
-- [ ] Add `output_messages` to Python `Turn.record()` for parity with
-      TypeScript `Turn.record({outputMessages: ...})`; the lower-level Python
-      `invoke_agent_attributes()` builder already supports agent output.
+- [ ] Reconcile Ruff 0.16's `RUF105` requirement to use `ruff: ignore` with
+      this file's instruction to use spot-level `# noqa` for intentional
+      `PLW` suppressions.
 - [ ] Repair the existing `pnpm run typecheck:examples` failures caused by
       OpenAI type drift in `examples/agent.ts`, `classesWithOps.ts`,
       `imageGeneration.ts`, `quickstart*.ts`, and `streamFunctionCalls.ts`.

tests/conversation/test_conversation_otel.py

@@ -963,12 +963,29 @@ def test_start_turn_system_instructions_param_emitted_on_span(
             {"type": "text", "content": "You are a weather bot"},
         ]
 
+    def test_start_turn_provider_name_param_emitted_on_span(
+        self, otel_spans: InMemorySpanExporter
+    ) -> None:
+        with Conversation(agent_name="bot", conversation_id="convo-provider") as s:
+            with s.start_turn(provider_name="anthropic"):
+                pass
+
+        spans = otel_spans.get_finished_spans()
+        turn_spans = [sp for sp in spans if sp.name == "invoke_agent bot"]
+        assert len(turn_spans) == 1
+        attrs = dict(turn_spans[0].attributes or {})
+        assert attrs["gen_ai.provider.name"] == "anthropic"
+
     def test_module_start_turn_system_instructions_param(self) -> None:
         # weave.start_turn(...) wires the field onto the returned Turn whether
         # or not a conversation is active (delegates to Conversation.start_turn when one is).
         turn = start_turn(system_instructions=["You are a weather bot"])
         assert turn.system_instructions == ["You are a weather bot"]
 
+    def test_module_start_turn_provider_name_param(self) -> None:
+        turn = start_turn(provider_name="anthropic")
+        assert turn.provider_name == "anthropic"
+
     def test_conversation_agent_identity_propagates_to_turn_span(
         self, otel_spans: InMemorySpanExporter
     ) -> None:
@@ -1549,6 +1566,20 @@ def test_agent_identity_fields_emitted(
         assert attrs["gen_ai.agent.description"] == "A helpful bot"
         assert attrs["gen_ai.agent.version"] == "v3"
 
+    def test_provider_name_emitted(self, otel_spans: InMemorySpanExporter) -> None:
+        log_turn(
+            conversation_id="convo-provider",
+            agent_name="bot",
+            provider_name="anthropic",
+            started_at=_ts(0),
+            ended_at=_ts(1),
+        )
+        spans = otel_spans.get_finished_spans()
+        turn_spans = [sp for sp in spans if sp.name == "invoke_agent bot"]
+        assert len(turn_spans) == 1
+        attrs = dict(turn_spans[0].attributes or {})
+        assert attrs["gen_ai.provider.name"] == "anthropic"
+
     def test_subagent_system_instructions_emitted(
         self, otel_spans: InMemorySpanExporter
     ) -> None:
@@ -1862,6 +1893,7 @@ def test_forwards_all_turn_fields(self, otel_spans: InMemorySpanExporter) -> Non
             turns=[
                 Turn(
                     agent_name="bot",
+                    provider_name="anthropic",
                     agent_id="agent-123",
                     agent_description="A helpful bot",
                     agent_version="v2",
@@ -1895,6 +1927,7 @@ def test_forwards_all_turn_fields(self, otel_spans: InMemorySpanExporter) -> Non
         assert attrs["gen_ai.agent.id"] == "agent-123"
         assert attrs["gen_ai.agent.description"] == "A helpful bot"
         assert attrs["gen_ai.agent.version"] == "v2"
+        assert attrs["gen_ai.provider.name"] == "anthropic"
 
     def test_agent_identity_defaults_applied(
         self, otel_spans: InMemorySpanExporter
@@ -2243,6 +2276,7 @@ def test_sets_all_fields(self) -> None:
             output_messages=[Message.assistant("hello")],
             system_instructions=["sys"],
             agent_name="bot",
+            provider_name="openai",
             model="gpt-4o",
             agent_id="id-1",
             agent_description="desc",
@@ -2252,6 +2286,7 @@ def test_sets_all_fields(self) -> None:
         assert turn.output_messages == [Message.assistant("hello")]
         assert turn.system_instructions == ["sys"]
         assert turn.agent_name == "bot"
+        assert turn.provider_name == "openai"
         assert turn.model == "gpt-4o"
         assert turn.agent_id == "id-1"
         assert turn.agent_description == "desc"

weave/conversation/conversation.py

@@ -961,6 +961,7 @@ class Turn(_SpanBase):
     """
 
     agent_name: str = ""
+    provider_name: str = ""
     model: str = ""
     agent_id: str = ""
     agent_description: str = ""
@@ -1078,6 +1079,7 @@ def record(
         output_messages: list[Message] | None = None,
         system_instructions: list[str] | None = None,
         agent_name: str | None = None,
+        provider_name: str | None = None,
         model: str | None = None,
         agent_id: str | None = None,
         agent_description: str | None = None,
@@ -1108,6 +1110,8 @@ def record(
             self.system_instructions = system_instructions
         if agent_name is not None:
             self.agent_name = agent_name
+        if provider_name is not None:
+            self.provider_name = provider_name
         if model is not None:
             self.model = model
         if agent_id is not None:
@@ -1148,6 +1152,7 @@ def _build_attrs(
             agent_name=self.agent_name,
             conversation_id=conversation_id,
             conversation_name=conversation_name,
+            provider_name=self.provider_name,
             model=self.model,
             input_messages=messages,
             output_messages=output_messages,
@@ -1251,6 +1256,7 @@ def start_turn(
         user_message: str = "",
         model: str = "",
         agent_name: str = "",
+        provider_name: str = "",
         agent_id: str = "",
         agent_description: str = "",
         agent_version: str = "",
@@ -1262,8 +1268,9 @@ def start_turn(
         ``get_current_turn()`` regardless of whether a context manager is used.
         Each of ``agent_name`` / ``model`` / ``agent_id`` / ``agent_description``
         / ``agent_version`` falls back to the conversation's default when left
-        empty; ``continue_parent_trace`` is inherited. Override any of them later
-        via ``turn.record(...)``.
+        empty; ``provider_name`` is specific to this turn and
+        ``continue_parent_trace`` is inherited. Override any typed turn field
+        later via ``turn.record(...)``.
 
         ``system_instructions`` (the agent's system prompt) is carried on the
         turn's invoke_agent span; it can also be set later via attribute
@@ -1273,6 +1280,7 @@ def start_turn(
             self._current_turn.end()
         turn = Turn(
             agent_name=agent_name or self.agent_name,
+            provider_name=provider_name,
             model=model or self.model,
             agent_id=agent_id or self.agent_id,
             agent_description=agent_description or self.agent_description,
@@ -1367,6 +1375,7 @@ def start_turn(
     user_message: str = "",
     model: str = "",
     agent_name: str = "",
+    provider_name: str = "",
     system_instructions: list[str] | None = None,
 ) -> Turn:
     """Create and activate a turn. Uses the current conversation if available.
@@ -1382,10 +1391,12 @@ def start_turn(
             user_message=user_message,
             model=model,
             agent_name=agent_name,
+            provider_name=provider_name,
             system_instructions=system_instructions,
         )
     turn = Turn(
         agent_name=agent_name,
+        provider_name=provider_name,
         model=model,
         system_instructions=system_instructions or [],
     )
@@ -1655,6 +1666,7 @@ def log_turn(
     conversation_id: str,
     agent_name: str = "",
     conversation_name: str = "",
+    provider_name: str = "",
     model: str = "",
     agent_id: str = "",
     agent_description: str = "",
@@ -1676,7 +1688,7 @@ def log_turn(
     ``ended_at`` set; the emitted OTel span timestamps come from those fields.
     Falls back to the earliest/latest child timestamp, then ``now()``, when
     the turn doesn't supply its own. ``agent_id`` / ``agent_description`` /
-    ``agent_version`` mirror the streaming path.
+    ``agent_version`` and ``provider_name`` mirror the streaming path.
 
     ``attributes`` are stamped on every emitted span; the streaming path reads
     these from the active conversation instead. Use custom, non-semconv keys: a
@@ -1700,6 +1712,7 @@ def log_turn(
     )
     turn = Turn(
         agent_name=agent_name,
+        provider_name=provider_name,
         model=model,
         agent_id=agent_id,
         agent_description=agent_description,