diff --git a/supabase/functions/cnpj-lookup/index.ts b/supabase/functions/cnpj-lookup/index.ts
index ac19add6d..439156133 100644
--- a/supabase/functions/cnpj-lookup/index.ts
+++ b/supabase/functions/cnpj-lookup/index.ts
@@ -48,6 +48,13 @@ Deno.serve(async (req) => {
     }
 
     const apiKey = Deno.env.get("CNPJA_API_KEY");
+    if (!apiKey) {
+      console.error("[cnpj-lookup] CNPJA_API_KEY não configurada");
+      return new Response(
+        JSON.stringify({ error: "Serviço de consulta CNPJ não configurado" }),
+        { status: 503, headers: { ...corsHeaders, "Content-Type": "application/json" } },
+      );
+    }
 
     // CNPJá Commercial API
     const response = await fetchWithBreaker(
diff --git a/supabase/functions/simulation-orchestrator/index.ts b/supabase/functions/simulation-orchestrator/index.ts
index 752dc2a05..7e5f16cac 100644
--- a/supabase/functions/simulation-orchestrator/index.ts
+++ b/supabase/functions/simulation-orchestrator/index.ts
@@ -218,7 +218,8 @@ serve(async (req) => {
       status: 200,
     });
   } catch (error) {
-    return new Response(JSON.stringify({ error: error.message }), {
+    const errorMessage = error instanceof Error ? error.message : String(error);
+    return new Response(JSON.stringify({ error: errorMessage }), {
       headers: { ...corsHeaders, "Content-Type": "application/json" },
       status: 400,
     });
diff --git a/supabase/functions/sync-external-db/index.ts b/supabase/functions/sync-external-db/index.ts
index 8a779ff75..47652293f 100644
--- a/supabase/functions/sync-external-db/index.ts
+++ b/supabase/functions/sync-external-db/index.ts
@@ -80,7 +80,8 @@ serve(async (req) => {
 
   } catch (error) {
     console.error("Sync error:", error);
-    return new Response(JSON.stringify({ error: error.message }), {
+    const errorMessage = error instanceof Error ? error.message : String(error);
+    return new Response(JSON.stringify({ error: errorMessage }), {
       status: 500,
       headers: { ...corsHeaders, "Content-Type": "application/json" },
     });