feat: Explicitly reject string values for "enable_thinking"

There are too many possible "truthy" / "falsy" strings and too many
ambiguous strings that don't have a clear truthy/falsy value, so the
simplest thing to do here is to reject the request. Ideally, this would be
a 422 (Unprocessable Entity), but right now it's coming back as a 500.

Branch: gabe-l-hart/thinking-model-disabled-agent-prefill

Signed-off-by: Gabe Goodhart <[email protected]>

Author: gabe-l-hart

tools/server/utils.hpp

@@ -772,6 +772,8 @@ static json oaicompat_chat_params_parse(
         inputs.enable_thinking = true;
     } else if (enable_thinking_kwarg == "false") {
         inputs.enable_thinking = false;
+    } else if (!enable_thinking_kwarg.empty() && enable_thinking_kwarg[0] == '"') {
+        throw std::runtime_error("invalid type for \"enable_thinking\" (expected boolean, got string)");
     }
 
     // if the assistant message appears at the end of list, we do not add end-of-turn token