From 5fe57f8afa39de947c957d7140d80ec01de314c3 Mon Sep 17 00:00:00 2001
From: 04cb <0x04cb@gmail.com>
Date: Fri, 29 May 2026 22:06:43 +0800
Subject: [PATCH] fix(providers): coerce typeless Anthropic content blocks to
 text (#3993)

---
 nanobot/providers/anthropic_provider.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/nanobot/providers/anthropic_provider.py b/nanobot/providers/anthropic_provider.py
index 31f2bc2f1..504c35ad0 100644
--- a/nanobot/providers/anthropic_provider.py
+++ b/nanobot/providers/anthropic_provider.py
@@ -228,6 +228,13 @@ class AnthropicProvider(LLMProvider):
                 if converted:
                     result.append(converted)
                 continue
+            if not item.get("type"):
+                # Anthropic requires every content block to declare a "type".
+                # A tool that returned a bare dict (or a list of dicts) lands
+                # here; coerce it to a text block instead of emitting a block
+                # the API rejects with "content.0.type: Field required".
+                result.append({"type": "text", "text": str(item)})
+                continue
             result.append(item)
         return result or "(empty)"