diff --git a/pkg/agent/loop.go b/pkg/agent/loop.go
index 235d42fcc..249d1fc3e 100644
--- a/pkg/agent/loop.go
+++ b/pkg/agent/loop.go
@@ -1091,9 +1091,10 @@ func (al *AgentLoop) runLLMIteration(
 			return "", iteration, fmt.Errorf("LLM call failed after retries: %w", err)
 		}
 
+		effectiveReasoning := response.EffectiveReasoning()
 		go al.handleReasoning(
 			ctx,
-			response.Reasoning,
+			effectiveReasoning,
 			opts.Channel,
 			al.targetReasoningChannelID(opts.Channel),
 		)
@@ -1104,7 +1105,7 @@ func (al *AgentLoop) runLLMIteration(
 				"iteration":      iteration,
 				"content_chars":  len(response.Content),
 				"tool_calls":     len(response.ToolCalls),
-				"reasoning":      response.Reasoning,
+				"reasoning":      effectiveReasoning,
 				"target_channel": al.targetReasoningChannelID(opts.Channel),
 				"channel":        opts.Channel,
 			})
diff --git a/pkg/providers/protocoltypes/types.go b/pkg/providers/protocoltypes/types.go
index 194c1aa6f..d83657ba9 100644
--- a/pkg/providers/protocoltypes/types.go
+++ b/pkg/providers/protocoltypes/types.go
@@ -34,6 +34,14 @@ type LLMResponse struct {
 	ReasoningDetails []ReasoningDetail `json:"reasoning_details"`
 }
 
+// EffectiveReasoning returns Reasoning if non-empty, otherwise ReasoningContent.
+func (r *LLMResponse) EffectiveReasoning() string {
+	if r.Reasoning != "" {
+		return r.Reasoning
+	}
+	return r.ReasoningContent
+}
+
 type ReasoningDetail struct {
 	Format string `json:"format"`
 	Index  int    `json:"index"`