diff --git a/agents/test-bot/config.yaml b/agents/test-bot/config.yaml
index 827bca2..cc4ad7e 100644
--- a/agents/test-bot/config.yaml
+++ b/agents/test-bot/config.yaml
@@ -43,7 +43,7 @@ matrix:
     admin: []
 
   filters:
-    command_prefix: "!"
+    command_prefix: ""          # sin prefijo — todo mensaje es un posible comando
     mention_respond: false
     dm_respond: false
     ignore_bots: true
diff --git a/internal/config/loader.go b/internal/config/loader.go
index 0f2275a..4bf891f 100644
--- a/internal/config/loader.go
+++ b/internal/config/loader.go
@@ -94,7 +94,7 @@ func validate(cfg *AgentConfig) error {
 	if cfg.Matrix.UserID == "" {
 		return fmt.Errorf("matrix.user_id is required")
 	}
-	if cfg.LLM.Primary.Provider == "" {
+	if cfg.Agent.Type != "robot" && cfg.LLM.Primary.Provider == "" {
 		return fmt.Errorf("llm.primary.provider is required")
 	}
 	return nil