diff --git a/editor/CMakeLists.txt b/editor/CMakeLists.txt
index 8f7d718..96cf8e4 100644
--- a/editor/CMakeLists.txt
+++ b/editor/CMakeLists.txt
@@ -4729,4 +4729,13 @@ target_link_libraries(step649_test PRIVATE
     tree_sitter_javascript tree_sitter_typescript
     tree_sitter_java tree_sitter_rust tree_sitter_go)
 
+add_executable(step650_test tests/step650_test.cpp)
+target_include_directories(step650_test PRIVATE src)
+target_link_libraries(step650_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/HiveMindAutoUpdateModel.h b/editor/src/HiveMindAutoUpdateModel.h
new file mode 100644
index 0000000..fcfa17c
--- /dev/null
+++ b/editor/src/HiveMindAutoUpdateModel.h
@@ -0,0 +1,41 @@
+#pragma once
+// Step 650: HiveMind-push auto-update mechanism model
+
+#include <string>
+
+struct UpdateJob {
+    std::string version;
+    std::string downloadUrl;
+    std::string expectedSha256;
+};
+
+struct UpdateExecutionResult {
+    bool accepted = false;
+    bool hashVerified = false;
+    bool binaryReplaced = false;
+    bool restartScheduled = false;
+};
+
+class HiveMindAutoUpdateModel {
+public:
+    static bool isValidJob(const UpdateJob& job) {
+        return !job.version.empty() && !job.downloadUrl.empty() && !job.expectedSha256.empty();
+    }
+
+    static bool verifyHash(const std::string& actualSha256,
+                           const std::string& expectedSha256) {
+        return !actualSha256.empty() && actualSha256 == expectedSha256;
+    }
+
+    static UpdateExecutionResult execute(const UpdateJob& job,
+                                         const std::string& downloadedSha256) {
+        UpdateExecutionResult out;
+        out.accepted = isValidJob(job);
+        if (!out.accepted) return out;
+        out.hashVerified = verifyHash(downloadedSha256, job.expectedSha256);
+        if (!out.hashVerified) return out;
+        out.binaryReplaced = true;
+        out.restartScheduled = true;
+        return out;
+    }
+};
diff --git a/editor/tests/step650_test.cpp b/editor/tests/step650_test.cpp
new file mode 100644
index 0000000..93e0489
--- /dev/null
+++ b/editor/tests/step650_test.cpp
@@ -0,0 +1,26 @@
+// Step 650: HiveMind-push auto-update mechanism (12 tests)
+
+#include "HiveMindAutoUpdateModel.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;}
+
+static UpdateJob job(){return {"1.2.3","https://apiary/whetstone.AppImage","abc123"};}
+
+void t1(){T(valid_job_true);C(HiveMindAutoUpdateModel::isValidJob(job()),"valid expected");P();}
+void t2(){T(invalid_job_missing_version);auto j=job();j.version="";C(!HiveMindAutoUpdateModel::isValidJob(j),"invalid expected");P();}
+void t3(){T(invalid_job_missing_url);auto j=job();j.downloadUrl="";C(!HiveMindAutoUpdateModel::isValidJob(j),"invalid expected");P();}
+void t4(){T(invalid_job_missing_hash);auto j=job();j.expectedSha256="";C(!HiveMindAutoUpdateModel::isValidJob(j),"invalid expected");P();}
+void t5(){T(hash_verify_true_for_match);C(HiveMindAutoUpdateModel::verifyHash("abc123","abc123"),"hash match");P();}
+void t6(){T(hash_verify_false_for_mismatch);C(!HiveMindAutoUpdateModel::verifyHash("abc124","abc123"),"hash mismatch");P();}
+void t7(){T(execute_rejects_invalid_job);auto j=job();j.version="";auto r=HiveMindAutoUpdateModel::execute(j,"abc123");C(!r.accepted,"should reject");P();}
+void t8(){T(execute_accepts_valid_job);auto r=HiveMindAutoUpdateModel::execute(job(),"abc123");C(r.accepted,"should accept");P();}
+void t9(){T(execute_sets_hash_verified_on_match);auto r=HiveMindAutoUpdateModel::execute(job(),"abc123");C(r.hashVerified,"hash verified");P();}
+void t10(){T(execute_blocks_replace_on_hash_mismatch);auto r=HiveMindAutoUpdateModel::execute(job(),"zzz");C(!r.binaryReplaced,"replace blocked");P();}
+void t11(){T(execute_replaces_binary_on_verified_hash);auto r=HiveMindAutoUpdateModel::execute(job(),"abc123");C(r.binaryReplaced,"replace expected");P();}
+void t12(){T(execute_schedules_restart_on_success);auto r=HiveMindAutoUpdateModel::execute(job(),"abc123");C(r.restartScheduled,"restart expected");P();}
+
+int main(){std::cout<<"Step 650: HiveMind auto-update mechanism\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 04b7f76..59d889d 100644
--- a/progress.md
+++ b/progress.md
@@ -13325,3 +13325,27 @@ project release attributes.
 - `editor/src/PackageScriptGenerator.h` (`29` <= `600`)
 - `editor/tests/step649_test.cpp` within test-file size guidance (`24` lines)
 - Header-only architecture and naming conventions remain aligned with `ARCHITECTURE.md`
+
+### Step 650: HiveMind-push auto-update mechanism
+**Status:** PASS (12/12 tests)
+
+Adds an auto-update execution model for `update_editor` jobs with job-shape
+validation, hash verification, binary replace gating, and restart scheduling.
+
+**Files added:**
+- `editor/src/HiveMindAutoUpdateModel.h` - update execution model
+- `editor/tests/step650_test.cpp` - 12 tests for validation, hash checks, and apply flow
+
+**Files modified:**
+- `editor/CMakeLists.txt` - `step650_test` target
+
+**Verification run:**
+- `cmake -S editor -B editor/build-native` - PASS
+- `cmake --build editor/build-native --target step650_test step649_test` - PASS
+- `./editor/build-native/step650_test` - PASS (12/12)
+- `./editor/build-native/step649_test` - PASS (12/12) regression coverage
+
+**Architecture gate check:**
+- `editor/src/HiveMindAutoUpdateModel.h` (`41` <= `600`)
+- `editor/tests/step650_test.cpp` within test-file size guidance (`26` lines)
+- Header-only architecture and naming conventions remain aligned with `ARCHITECTURE.md`