diff --git a/presets/lean/commands/speckit.constitution.md b/presets/lean/commands/speckit.constitution.md
index 920337003e..32dcd6b3df 100644
--- a/presets/lean/commands/speckit.constitution.md
+++ b/presets/lean/commands/speckit.constitution.md
@@ -8,6 +8,24 @@ description: Create or update the project constitution.
 $ARGUMENTS
 ```
 
+## Scope Guard
+
+This command's own work is limited to creating or updating the project constitution and
+propagating constitution-driven changes to dependent Spec Kit artifacts.
+
+- Classify every part of the user input as constitution content or a separate non-governance
+  intent. Feature implementation, code generation, refactoring, build, and deployment requests
+  are examples of non-governance intents.
+- You **MUST NOT** execute any non-governance intent. Defer each one to `Next Actions`.
+- You **MUST NOT** create, modify, or delete application source files or other artifacts
+  unrelated to the constitution workflow.
+- If an instruction could be either constitution content or a non-governance intent, ask for
+  clarification before making changes.
+- After updating the constitution, list each deferred intent in a `Next Actions` section with an
+  appropriate follow-up Spec Kit command, such as `__SPECKIT_COMMAND_SPECIFY__`, but do not
+  invoke it.
+- Omit `Next Actions` when there are no non-governance intents.
+
 ## Outline
 
 1. Create or update the project constitution and store it in `.specify/memory/constitution.md`.
diff --git a/templates/commands/constitution.md b/templates/commands/constitution.md
index 9d2d4ccc1a..f4f549043e 100644
--- a/templates/commands/constitution.md
+++ b/templates/commands/constitution.md
@@ -14,6 +14,25 @@ $ARGUMENTS
 
 You **MUST** consider the user input before proceeding (if not empty).
 
+## Scope Guard
+
+This command's own work is limited to updating the project constitution and propagating
+constitution-driven changes to the dependent artifacts identified in this command.
+
+- Classify every part of the user input as either constitution content or a separate,
+  non-governance intent.
+- If the input includes feature implementation, code generation, refactoring, building, or
+  deployment requests, you **MUST NOT** execute them. Extract them as deferred intents instead.
+- You **MUST NOT** create, modify, or delete application source files, feature routes,
+  components, tests, deployment files, or other artifacts unrelated to the constitution
+  workflow and its required propagation.
+- If it is unclear whether an instruction is constitution content, ask for clarification before
+  making changes.
+- After completing the constitution update, include a `Next Actions` section for each deferred
+  intent. List the original intent and suggest the appropriate follow-up Spec Kit command, such
+  as `__SPECKIT_COMMAND_SPECIFY__`, without invoking it.
+- If there are no non-governance intents, omit the `Next Actions` section.
+
 ## Pre-Execution Checks
 
 **Check for extension hooks (before constitution update)**:
@@ -104,6 +123,7 @@ Follow this execution flow:
    - New version and bump rationale.
    - Any files flagged for manual follow-up.
    - Suggested commit message (e.g., `docs: amend constitution to vX.Y.Z (principle additions + governance update)`).
+   - A `Next Actions` section for any deferred non-governance intents.
 
 Formatting & Style Requirements:
 
diff --git a/tests/test_presets.py b/tests/test_presets.py
index aeceaf6a8b..314524e265 100644
--- a/tests/test_presets.py
+++ b/tests/test_presets.py
@@ -5381,6 +5381,9 @@ def test_disable_corrupted_registry_entry(self, project_dir, pack_dir):
 
 
 LEAN_PRESET_DIR = Path(__file__).parent.parent / "presets" / "lean"
+CORE_CONSTITUTION_COMMAND = (
+    Path(__file__).parent.parent / "templates" / "commands" / "constitution.md"
+)
 
 LEAN_COMMAND_NAMES = [
     "speckit.specify",
@@ -5391,6 +5394,31 @@ def test_disable_corrupted_registry_entry(self, project_dir, pack_dir):
 ]
 
 
+@pytest.mark.parametrize(
+    "command_path",
+    [
+        CORE_CONSTITUTION_COMMAND,
+        LEAN_PRESET_DIR / "commands" / "speckit.constitution.md",
+    ],
+    ids=["core", "lean"],
+)
+def test_constitution_commands_guard_against_non_governance_work(command_path):
+    """Constitution commands defer non-governance work instead of executing it."""
+    content = command_path.read_text()
+    lower_content = content.lower()
+    normalized_content = " ".join(lower_content.split())
+
+    assert "## Scope Guard" in content
+    assert "**MUST NOT**" in content
+    assert "Classify every part" in content
+    assert "application source files" in content
+    assert "non-governance intent" in content
+    assert "`Next Actions`" in content
+    assert "__SPECKIT_COMMAND_SPECIFY__" in content
+    assert "omit" in lower_content
+    assert "do not invoke it" in normalized_content or "without invoking it" in normalized_content
+
+
 class TestLeanPreset:
     """Tests for the lean preset that ships with the repo."""