fix(anthropic): echo thinking-bearing assistant turns verbatim in tool loops

With adaptive thinking, the Messages API rejects tool-loop follow-ups
whose latest assistant message differs from the original response
(thinking signatures bind block positions; text/tool_use siblings were
rebuilt and thinking blocks hoisted). The signature payload now carries
the full native content array when thinking blocks are present — both
parse paths — and _init_request re-emits it unchanged. Thinking-only
signature payloads (from older versions) keep the rebuild path.

Author: Kamilbenkirane

src/celeste/modalities/text/providers/anthropic/client.py

@@ -92,9 +92,10 @@ def _aggregate_signature(
     ) -> list[dict[str, Any]]:
         """Return the full native content array when the turn carries thinking blocks."""
         blocks = self._aggregate_content_blocks()
-        if any(b.get("type") in {"thinking", "redacted_thinking"} for b in blocks):
-            return blocks
-        return []
+        has_thinking = any(
+            b.get("type") in {"thinking", "redacted_thinking"} for b in blocks
+        )
+        return blocks if has_thinking else []
 
     def _aggregate_grounding(
         self, chunks: list[TextChunk], raw_events: list[dict[str, Any]]
@@ -272,17 +273,14 @@ def _parse_reasoning(
     ) -> tuple[str | None, list[dict[str, Any]]]:
         """Parse thinking from Anthropic response (signature = full content array)."""
         blocks = response_data.get("content", [])
-        reasoning_parts: list[str] = []
-        has_thinking = False
-        for block in blocks:
-            block_type = block.get("type")
-            if block_type == "thinking":
-                has_thinking = True
-                thinking_text = block.get("thinking", "")
-                if thinking_text:
-                    reasoning_parts.append(thinking_text)
-            elif block_type == "redacted_thinking":
-                has_thinking = True
+        reasoning_parts = [
+            b["thinking"]
+            for b in blocks
+            if b.get("type") == "thinking" and b.get("thinking")
+        ]
+        has_thinking = any(
+            b.get("type") in {"thinking", "redacted_thinking"} for b in blocks
+        )
         text = "\n".join(reasoning_parts) if reasoning_parts else None
         return text, list(blocks) if has_thinking else []
 

src/celeste/providers/anthropic/messages/streaming.py

@@ -61,12 +61,10 @@ def _parse_chunk(self, event_data: dict[str, Any]) -> Any:  # noqa: ANN401
             if delta_type == "input_json_delta":
                 if block and block.get("type") in {"server_tool_use", "tool_use"}:
                     block["input_json"] += delta.get("partial_json", "")
-            elif delta_type == "thinking_delta":
+            elif delta_type in {"thinking_delta", "signature_delta"}:
+                key = delta_type.removesuffix("_delta")
                 if block and block.get("type") == "thinking":
-                    block["thinking"] += delta.get("thinking", "")
-            elif delta_type == "signature_delta":
-                if block and block.get("type") == "thinking":
-                    block["signature"] += delta.get("signature", "")
+                    block[key] += delta.get(key, "")
             elif delta_type in {"text_delta", "citations_delta"}:
                 block = self._content_blocks.setdefault(
                     idx, {"type": "text", "text": "", "citations": []}