diff --git a/esphome/components/mdns/__init__.py b/esphome/components/mdns/__init__.py
index 7625b28408..6e148092fe 100644
--- a/esphome/components/mdns/__init__.py
+++ b/esphome/components/mdns/__init__.py
@@ -126,9 +126,11 @@ async def to_code(config):
             if cg.is_template(txt_value):
                 # It's a lambda - evaluate and store using helper
                 templated_value = await cg.templatable(txt_value, [], cg.std_string)
+                safe_key = cg.safe_exp(txt_key)
+                dynamic_call = f"{var}->add_dynamic_txt_value(({templated_value})())"
                 txt_records.append(
                     cg.RawExpression(
-                        f"{{MDNS_STR({cg.safe_exp(txt_key)}), MDNS_STR({var}->add_dynamic_txt_value(({templated_value})()))}}"
+                        f"{{MDNS_STR({safe_key}), MDNS_STR({dynamic_call})}}"
                     )
                 )
             else:
diff --git a/esphome/components/mdns/mdns_component.cpp b/esphome/components/mdns/mdns_component.cpp
index d1fc28eee6..8ab14fa935 100644
--- a/esphome/components/mdns/mdns_component.cpp
+++ b/esphome/components/mdns/mdns_component.cpp
@@ -132,9 +132,9 @@ void MDNSComponent::compile_records_() {
 
 #ifdef USE_API_NOISE
     MDNS_STATIC_CONST_CHAR(NOISE_ENCRYPTION, "Noise_NNpsk0_25519_ChaChaPoly_SHA256");
-    txt_records.push_back({MDNS_STR(api::global_api_server->get_noise_ctx()->has_psk() ? TXT_API_ENCRYPTION
-                                                                                       : TXT_API_ENCRYPTION_SUPPORTED),
-                           MDNS_STR(NOISE_ENCRYPTION)});
+    bool has_psk = api::global_api_server->get_noise_ctx()->has_psk();
+    const char *encryption_key = has_psk ? TXT_API_ENCRYPTION : TXT_API_ENCRYPTION_SUPPORTED;
+    txt_records.push_back({MDNS_STR(encryption_key), MDNS_STR(NOISE_ENCRYPTION)});
 #endif
 
 #ifdef ESPHOME_PROJECT_NAME
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 2317c0ed32..0f1d1bcf28 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -84,6 +84,7 @@
 #define USE_LVGL_TOUCHSCREEN
 #define USE_MDNS
 #define MDNS_SERVICE_COUNT 3
+#define MDNS_DYNAMIC_TXT_COUNT 3
 #define USE_MEDIA_PLAYER
 #define USE_NEXTION_TFT_UPLOAD
 #define USE_NUMBER
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index cbb71134fd..c36ecf6f5d 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -149,8 +149,14 @@ template<typename T, size_t N> class StaticVector {
   T &operator[](size_t i) { return data_[i]; }
   const T &operator[](size_t i) const { return data_[i]; }
 
-  T &back() { return data_[count_ - 1]; }
-  const T &back() const { return data_[count_ - 1]; }
+  T &back() {
+    assert(count_ > 0 && "back() called on empty StaticVector");
+    return data_[count_ - 1];
+  }
+  const T &back() const {
+    assert(count_ > 0 && "back() called on empty StaticVector");
+    return data_[count_ - 1];
+  }
 
   // For range-based for loops
   iterator begin() { return data_.begin(); }