diff --git a/editor/CMakeLists.txt b/editor/CMakeLists.txt
index 4a3755f..63fa75c 100644
--- a/editor/CMakeLists.txt
+++ b/editor/CMakeLists.txt
@@ -4792,4 +4792,13 @@ target_link_libraries(step656_test PRIVATE
     tree_sitter_javascript tree_sitter_typescript
     tree_sitter_java tree_sitter_rust tree_sitter_go)
 
+add_executable(step657_test tests/step657_test.cpp)
+target_include_directories(step657_test PRIVATE src)
+target_link_libraries(step657_test PRIVATE
+    nlohmann_json::nlohmann_json
+    unofficial::tree-sitter::tree-sitter
+    tree_sitter_python tree_sitter_cpp tree_sitter_elisp
+    tree_sitter_javascript tree_sitter_typescript
+    tree_sitter_java tree_sitter_rust tree_sitter_go)
+
 # Step 12: Dear ImGui shell scaffolding created (main.cpp exists but not built due to dependencies)
diff --git a/editor/src/EnergyContextStatusModel.h b/editor/src/EnergyContextStatusModel.h
new file mode 100644
index 0000000..cb490dc
--- /dev/null
+++ b/editor/src/EnergyContextStatusModel.h
@@ -0,0 +1,28 @@
+#pragma once
+// Step 657: Energy context status bar model
+
+#include <string>
+
+struct EnergyContextState {
+    std::string mode = "Normal";
+    int watts = 0;
+    int batteryPercent = 100;
+};
+
+class EnergyContextStatusModel {
+public:
+    static std::string statusLabel(const EnergyContextState& e) {
+        if (e.mode == "Conservation") {
+            return "Conservation " + std::to_string(e.batteryPercent) + "%";
+        }
+        return e.mode + " " + std::to_string(e.watts) + "W";
+    }
+
+    static bool shouldFlashOrange(const EnergyContextState& e) {
+        return e.mode == "Conservation" || e.batteryPercent < 30;
+    }
+
+    static std::string promptContextLine(const EnergyContextState& e) {
+        return "energyState: " + statusLabel(e);
+    }
+};
diff --git a/editor/tests/step657_test.cpp b/editor/tests/step657_test.cpp
new file mode 100644
index 0000000..0acdbc5
--- /dev/null
+++ b/editor/tests/step657_test.cpp
@@ -0,0 +1,24 @@
+// Step 657: Energy context status bar (12 tests)
+
+#include "EnergyContextStatusModel.h"
+#include <iostream>
+static int p=0,f=0;
+#define T(n) { std::cout<<"  "<<#n<<"... "; }
+#define P() { std::cout<<"PASS\n"; ++p; }
+#define F(m) { std::cout<<"FAIL: "<<m<<"\n"; ++f; }
+#define C(c,m) if(!(c)){F(m);return;}
+
+void t1(){T(label_for_high_solar_uses_watts);EnergyContextState e{"HighSolar",450,80};C(EnergyContextStatusModel::statusLabel(e)=="HighSolar 450W","label");P();}
+void t2(){T(label_for_conservation_uses_percent);EnergyContextState e{"Conservation",120,28};C(EnergyContextStatusModel::statusLabel(e)=="Conservation 28%","label");P();}
+void t3(){T(flash_true_for_conservation);EnergyContextState e{"Conservation",120,50};C(EnergyContextStatusModel::shouldFlashOrange(e),"flash");P();}
+void t4(){T(flash_true_for_low_battery);EnergyContextState e{"Normal",120,20};C(EnergyContextStatusModel::shouldFlashOrange(e),"flash");P();}
+void t5(){T(flash_false_for_normal_high_battery);EnergyContextState e{"Normal",120,80};C(!EnergyContextStatusModel::shouldFlashOrange(e),"no flash");P();}
+void t6(){T(prompt_context_line_prefix);EnergyContextState e{"Normal",100,70};C(EnergyContextStatusModel::promptContextLine(e).find("energyState:")==0,"prefix");P();}
+void t7(){T(prompt_context_includes_label);EnergyContextState e{"HighSolar",450,80};C(EnergyContextStatusModel::promptContextLine(e).find("HighSolar 450W")!=std::string::npos,"content");P();}
+void t8(){T(default_state_label);EnergyContextState e;C(EnergyContextStatusModel::statusLabel(e)=="Normal 0W","default");P();}
+void t9(){T(conservation_low_battery_still_percent_label);EnergyContextState e{"Conservation",10,5};C(EnergyContextStatusModel::statusLabel(e)=="Conservation 5%","label");P();}
+void t10(){T(battery_threshold_30_not_flashing);EnergyContextState e{"Normal",100,30};C(!EnergyContextStatusModel::shouldFlashOrange(e),"threshold");P();}
+void t11(){T(battery_threshold_29_flashing);EnergyContextState e{"Normal",100,29};C(EnergyContextStatusModel::shouldFlashOrange(e),"threshold");P();}
+void t12(){T(prompt_context_for_conservation);EnergyContextState e{"Conservation",120,28};C(EnergyContextStatusModel::promptContextLine(e).find("Conservation 28%")!=std::string::npos,"prompt");P();}
+
+int main(){std::cout<<"Step 657: Energy context status model\n";t1();t2();t3();t4();t5();t6();t7();t8();t9();t10();t11();t12();std::cout<<"\nResults: "<<p<<"/"<<(p+f)<<" passed\n";return f?1:0;}
diff --git a/progress.md b/progress.md
index f5567d2..72734ef 100644
--- a/progress.md
+++ b/progress.md
@@ -13528,3 +13528,27 @@ tool title/source metadata presentation.
 - `editor/src/ApiaryBrowserPanelModel.h` (`36` <= `600`)
 - `editor/tests/step656_test.cpp` within test-file size guidance (`29` lines)
 - Header-only architecture and naming conventions remain aligned with `ARCHITECTURE.md`
+
+### Step 657: Energy context status bar
+**Status:** PASS (12/12 tests)
+
+Adds energy-context status modeling for status-bar label generation, conservation
+flash signaling, and agent prompt-context line composition.
+
+**Files added:**
+- `editor/src/EnergyContextStatusModel.h` - energy status/prompt model
+- `editor/tests/step657_test.cpp` - 12 tests for label/flash/prompt behavior
+
+**Files modified:**
+- `editor/CMakeLists.txt` - `step657_test` target
+
+**Verification run:**
+- `cmake -S editor -B editor/build-native` - PASS
+- `cmake --build editor/build-native --target step657_test step656_test` - PASS
+- `./editor/build-native/step657_test` - PASS (12/12)
+- `./editor/build-native/step656_test` - PASS (12/12) regression coverage
+
+**Architecture gate check:**
+- `editor/src/EnergyContextStatusModel.h` (`28` <= `600`)
+- `editor/tests/step657_test.cpp` within test-file size guidance (`24` lines)
+- Header-only architecture and naming conventions remain aligned with `ARCHITECTURE.md`