diff --git a/loopx/cli_commands/action_help.py b/loopx/cli_commands/action_help.py
index c714eda32d..f998b54efa 100644
--- a/loopx/cli_commands/action_help.py
+++ b/loopx/cli_commands/action_help.py
@@ -23,7 +23,12 @@ def __call__(self, parser, namespace, values, option_string=None):
             fields = set(allowed) | set(self.common_fields) | {self.dest}
             actions = [action for action in parser._actions if action.dest in fields]
             formatter = parser.formatter_class(prog=f"{parser.prog} {command}")
-            formatter.add_usage(None, actions, [])
+            # Option declarations below retain the complete action grammar.
+            # A second long list in usage only repeats it (and can itself be
+            # truncated before the descriptions). Keep parser-required inputs.
+            required = [action for action in actions if action.required]
+            optional = argparse.Action([], dest="options", metavar="options", nargs="?")
+            formatter.add_usage(None, [*required, optional], [])
             formatter.add_text("Options for this action. Conditional requirements and "
                                "state/authority checks still apply. Global --registry "
                                "and --runtime-root go before the command.")
diff --git a/loopx/cli_commands/todo_argument_validation.py b/loopx/cli_commands/todo_argument_validation.py
index 969994b3b7..b72756a4f1 100644
--- a/loopx/cli_commands/todo_argument_validation.py
+++ b/loopx/cli_commands/todo_argument_validation.py
@@ -139,8 +139,8 @@
 )
 _TODO_OPTION_FLAGS = {field: flag for flag, field in TODO_OPTION_FIELDS}
 
-# The same strict subset drives validation and action help. Complex lifecycle
-# commands retain full help until their conditional grammar is centralized.
+# Read/claim subsets share validation and help. Update help reuses the mutable
+# field owner; other lifecycle commands retain full help until centralized.
 TODO_ACTION_FIELDS = {
     "list": frozenset({"role", "todo_id", "status", "agent_id", "todo_limit", "todo_thin", "state_file", "project", "dry_run"}),
     "receipt": frozenset({"operation_id"}),
@@ -149,6 +149,10 @@
     "project-markdown": frozenset({"state_file", "execute", "provider_revision", "project"}),
     "claim": frozenset({"role", "todo_id", "claimed_by", "agent_id", "state_file",
                         "claim_operation_id", "task_lease_idempotency_key", "task_lease_expected_version", "project", "dry_run"}),
+    "update": frozenset(_TODO_UPDATE_MUTABLE_FIELDS) | frozenset({
+        "role", "todo_id", "agent_id", "state_file", "project", "dry_run", "authority_reason",
+        "claim_operation_id", "update_operation_id", "update_expected_provider_revision",
+    }),
 }
 
 
diff --git a/tests/control_plane/test_cli_action_help.py b/tests/control_plane/test_cli_action_help.py
index 5982ef727c..e39e2c23a6 100644
--- a/tests/control_plane/test_cli_action_help.py
+++ b/tests/control_plane/test_cli_action_help.py
@@ -19,6 +19,8 @@
     (["todo", "list"], ["--todo-id", "--thin", "--limit"], ["--claimed-by", "--next-agent-todo"]),
     (["todo", "claim"], ["--claimed-by", "--claim-operation-id"],
      ["--note", "--next-agent-todo", "--task-lease-expected-version", "--task-lease-idempotency-key"]),
+    (["todo", "update"], ["--note", "--update-operation-id", "--validation-command", "--resume-when"],
+     ["--next-agent-todo", "--decision-outcome", "--result-file", "--task-lease-expected-version"]),
     (["todo", "receipt"], ["--operation-id"], ["--todo-id", "--claimed-by"]),
     (["todo", "result-read"], ["--todo-id"], ["--text", "--claimed-by"]),
     (["todo", "plan"], ["--agent-id", "--text"], ["--claimed-by", "--todo-id"]),
@@ -38,6 +40,20 @@ def test_action_help_from_real_cli_with_unavailable_registry(tmp_path, command,
     assert not registry.exists()
 
 
+def test_action_help_keeps_required_usage_and_lists_optional_grammar_once(capsys):
+    parser = build_parser()
+    command = ["todo", "update", "--goal-id", "fixture", "--todo-id", "todo_a", "--note", "progress"]
+    before = vars(parser.parse_args(command))
+    with pytest.raises(SystemExit) as exited:
+        parser.parse_args(["todo", "update", "--help"])
+    assert exited.value.code == 0
+    output = capsys.readouterr().out
+    usage = output.split("\n\n", 1)[0]
+    assert "--goal-id" in usage and "[options]" in usage
+    assert "--note" not in usage and "--note NOTE" in output
+    assert vars(parser.parse_args(command)) == before
+
+
 def test_help_does_not_mutate_reused_parser_or_change_claim_input(capsys):
     parser = build_parser()
     command = ["todo", "claim", "--goal-id", "fixture", "--todo-id", "todo_a",