feat: add Cmd/Ctrl+Enter send setting (#25062)

Adds an Agents General setting to require Cmd/Ctrl+Enter before sending
chat messages. When enabled, plain Enter inserts a newline in agent chat
inputs while the send button remains available.

The preference is now persisted server-side through
`/api/v2/users/{user}/preferences`, alongside the existing user
preference settings, and is applied to both the create-agent input and
existing chat composer. Storybook and API coverage verify the setting,
keyboard behavior, validation, and persistence.

<details>
<summary>Coder Agents notes</summary>

Generated by Coder Agents from a Slack request. Dogfooded with
agent-browser against the Storybook settings and chat input stories.

</details>

coderd/apidoc/docs.go

@@ -14909,6 +14909,17 @@ const docTemplate = `{
                 }
             }
         },
+        "codersdk.AgentChatSendShortcut": {
+            "type": "string",
+            "enum": [
+                "enter",
+                "modifier_enter"
+            ],
+            "x-enum-varnames": [
+                "AgentChatSendShortcutEnter",
+                "AgentChatSendShortcutModifierEnter"
+            ]
+        },
         "codersdk.AgentConnectionTiming": {
             "type": "object",
             "properties": {
@@ -23426,6 +23437,9 @@ const docTemplate = `{
         "codersdk.UpdateUserPreferenceSettingsRequest": {
             "type": "object",
             "properties": {
+                "agent_chat_send_shortcut": {
+                    "$ref": "#/definitions/codersdk.AgentChatSendShortcut"
+                },
                 "code_diff_display_mode": {
                     "$ref": "#/definitions/codersdk.AgentDisplayMode"
                 },
@@ -23899,6 +23913,9 @@ const docTemplate = `{
         "codersdk.UserPreferenceSettings": {
             "type": "object",
             "properties": {
+                "agent_chat_send_shortcut": {
+                    "$ref": "#/definitions/codersdk.AgentChatSendShortcut"
+                },
                 "code_diff_display_mode": {
                     "$ref": "#/definitions/codersdk.AgentDisplayMode"
                 },

coderd/apidoc/swagger.json

@@ -13375,6 +13375,14 @@
 				}
 			}
 		},
+		"codersdk.AgentChatSendShortcut": {
+			"type": "string",
+			"enum": ["enter", "modifier_enter"],
+			"x-enum-varnames": [
+				"AgentChatSendShortcutEnter",
+				"AgentChatSendShortcutModifierEnter"
+			]
+		},
 		"codersdk.AgentConnectionTiming": {
 			"type": "object",
 			"properties": {
@@ -21566,6 +21574,9 @@
 		"codersdk.UpdateUserPreferenceSettingsRequest": {
 			"type": "object",
 			"properties": {
+				"agent_chat_send_shortcut": {
+					"$ref": "#/definitions/codersdk.AgentChatSendShortcut"
+				},
 				"code_diff_display_mode": {
 					"$ref": "#/definitions/codersdk.AgentDisplayMode"
 				},
@@ -22010,6 +22021,9 @@
 		"codersdk.UserPreferenceSettings": {
 			"type": "object",
 			"properties": {
+				"agent_chat_send_shortcut": {
+					"$ref": "#/definitions/codersdk.AgentChatSendShortcut"
+				},
 				"code_diff_display_mode": {
 					"$ref": "#/definitions/codersdk.AgentDisplayMode"
 				},

coderd/database/dbauthz/dbauthz.go

@@ -4346,6 +4346,17 @@ func (q *querier) GetUserActivityInsights(ctx context.Context, arg database.GetU
 	return q.db.GetUserActivityInsights(ctx, arg)
 }
 
+func (q *querier) GetUserAgentChatSendShortcut(ctx context.Context, userID uuid.UUID) (string, error) {
+	user, err := q.db.GetUserByID(ctx, userID)
+	if err != nil {
+		return "", err
+	}
+	if err := q.authorizeContext(ctx, policy.ActionReadPersonal, user); err != nil {
+		return "", err
+	}
+	return q.db.GetUserAgentChatSendShortcut(ctx, userID)
+}
+
 func (q *querier) GetUserByEmailOrUsername(ctx context.Context, arg database.GetUserByEmailOrUsernameParams) (database.User, error) {
 	return fetch(q.log, q.auth, q.db.GetUserByEmailOrUsername)(ctx, arg)
 }
@@ -7010,6 +7021,17 @@ func (q *querier) UpdateUsageEventsPostPublish(ctx context.Context, arg database
 	return q.db.UpdateUsageEventsPostPublish(ctx, arg)
 }
 
+func (q *querier) UpdateUserAgentChatSendShortcut(ctx context.Context, arg database.UpdateUserAgentChatSendShortcutParams) (string, error) {
+	user, err := q.db.GetUserByID(ctx, arg.UserID)
+	if err != nil {
+		return "", err
+	}
+	if err := q.authorizeContext(ctx, policy.ActionUpdatePersonal, user); err != nil {
+		return "", err
+	}
+	return q.db.UpdateUserAgentChatSendShortcut(ctx, arg)
+}
+
 func (q *querier) UpdateUserChatCompactionThreshold(ctx context.Context, arg database.UpdateUserChatCompactionThresholdParams) (database.UserConfig, error) {
 	u, err := q.db.GetUserByID(ctx, arg.UserID)
 	if err != nil {

coderd/database/dbauthz/dbauthz_test.go

@@ -2842,6 +2842,19 @@ func (s *MethodTestSuite) TestUser() {
 		dbm.EXPECT().UpdateUserCodeDiffDisplayMode(gomock.Any(), arg).Return("always_collapsed", nil).AnyTimes()
 		check.Args(arg).Asserts(u, policy.ActionUpdatePersonal).Returns("always_collapsed")
 	}))
+	s.Run("GetUserAgentChatSendShortcut", s.Mocked(func(dbm *dbmock.MockStore, faker *gofakeit.Faker, check *expects) {
+		u := testutil.Fake(s.T(), faker, database.User{})
+		dbm.EXPECT().GetUserByID(gomock.Any(), u.ID).Return(u, nil).AnyTimes()
+		dbm.EXPECT().GetUserAgentChatSendShortcut(gomock.Any(), u.ID).Return("modifier_enter", nil).AnyTimes()
+		check.Args(u.ID).Asserts(u, policy.ActionReadPersonal).Returns("modifier_enter")
+	}))
+	s.Run("UpdateUserAgentChatSendShortcut", s.Mocked(func(dbm *dbmock.MockStore, faker *gofakeit.Faker, check *expects) {
+		u := testutil.Fake(s.T(), faker, database.User{})
+		arg := database.UpdateUserAgentChatSendShortcutParams{UserID: u.ID, AgentChatSendShortcut: "modifier_enter"}
+		dbm.EXPECT().GetUserByID(gomock.Any(), u.ID).Return(u, nil).AnyTimes()
+		dbm.EXPECT().UpdateUserAgentChatSendShortcut(gomock.Any(), arg).Return("modifier_enter", nil).AnyTimes()
+		check.Args(arg).Asserts(u, policy.ActionUpdatePersonal).Returns("modifier_enter")
+	}))
 	s.Run("ListUserChatCompactionThresholds", s.Mocked(func(dbm *dbmock.MockStore, faker *gofakeit.Faker, check *expects) {
 		u := testutil.Fake(s.T(), faker, database.User{})
 		uc := database.UserConfig{UserID: u.ID, Key: codersdk.ChatCompactionThresholdKeyPrefix + "00000000-0000-0000-0000-000000000001", Value: "75"}

coderd/database/dbmetrics/querymetrics.go

@@ -2793,6 +2793,14 @@ func (m queryMetricsStore) GetUserActivityInsights(ctx context.Context, arg data
 	return r0, r1
 }
 
+func (m queryMetricsStore) GetUserAgentChatSendShortcut(ctx context.Context, userID uuid.UUID) (string, error) {
+	start := time.Now()
+	r0, r1 := m.s.GetUserAgentChatSendShortcut(ctx, userID)
+	m.queryLatencies.WithLabelValues("GetUserAgentChatSendShortcut").Observe(time.Since(start).Seconds())
+	m.queryCounts.WithLabelValues(httpmw.ExtractHTTPRoute(ctx), httpmw.ExtractHTTPMethod(ctx), "GetUserAgentChatSendShortcut").Inc()
+	return r0, r1
+}
+
 func (m queryMetricsStore) GetUserByEmailOrUsername(ctx context.Context, arg database.GetUserByEmailOrUsernameParams) (database.User, error) {
 	start := time.Now()
 	r0, r1 := m.s.GetUserByEmailOrUsername(ctx, arg)
@@ -5001,6 +5009,14 @@ func (m queryMetricsStore) UpdateUsageEventsPostPublish(ctx context.Context, arg
 	return r0
 }
 
+func (m queryMetricsStore) UpdateUserAgentChatSendShortcut(ctx context.Context, arg database.UpdateUserAgentChatSendShortcutParams) (string, error) {
+	start := time.Now()
+	r0, r1 := m.s.UpdateUserAgentChatSendShortcut(ctx, arg)
+	m.queryLatencies.WithLabelValues("UpdateUserAgentChatSendShortcut").Observe(time.Since(start).Seconds())
+	m.queryCounts.WithLabelValues(httpmw.ExtractHTTPRoute(ctx), httpmw.ExtractHTTPMethod(ctx), "UpdateUserAgentChatSendShortcut").Inc()
+	return r0, r1
+}
+
 func (m queryMetricsStore) UpdateUserChatCompactionThreshold(ctx context.Context, arg database.UpdateUserChatCompactionThresholdParams) (database.UserConfig, error) {
 	start := time.Now()
 	r0, r1 := m.s.UpdateUserChatCompactionThreshold(ctx, arg)

coderd/database/dbmock/dbmock.go

@@ -5223,6 +5223,21 @@ func (mr *MockStoreMockRecorder) GetUserActivityInsights(ctx, arg any) *gomock.C
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetUserActivityInsights", reflect.TypeOf((*MockStore)(nil).GetUserActivityInsights), ctx, arg)
 }
 
+// GetUserAgentChatSendShortcut mocks base method.
+func (m *MockStore) GetUserAgentChatSendShortcut(ctx context.Context, userID uuid.UUID) (string, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "GetUserAgentChatSendShortcut", ctx, userID)
+	ret0, _ := ret[0].(string)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// GetUserAgentChatSendShortcut indicates an expected call of GetUserAgentChatSendShortcut.
+func (mr *MockStoreMockRecorder) GetUserAgentChatSendShortcut(ctx, userID any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetUserAgentChatSendShortcut", reflect.TypeOf((*MockStore)(nil).GetUserAgentChatSendShortcut), ctx, userID)
+}
+
 // GetUserByEmailOrUsername mocks base method.
 func (m *MockStore) GetUserByEmailOrUsername(ctx context.Context, arg database.GetUserByEmailOrUsernameParams) (database.User, error) {
 	m.ctrl.T.Helper()
@@ -9427,6 +9442,21 @@ func (mr *MockStoreMockRecorder) UpdateUsageEventsPostPublish(ctx, arg any) *gom
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "UpdateUsageEventsPostPublish", reflect.TypeOf((*MockStore)(nil).UpdateUsageEventsPostPublish), ctx, arg)
 }
 
+// UpdateUserAgentChatSendShortcut mocks base method.
+func (m *MockStore) UpdateUserAgentChatSendShortcut(ctx context.Context, arg database.UpdateUserAgentChatSendShortcutParams) (string, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "UpdateUserAgentChatSendShortcut", ctx, arg)
+	ret0, _ := ret[0].(string)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// UpdateUserAgentChatSendShortcut indicates an expected call of UpdateUserAgentChatSendShortcut.
+func (mr *MockStoreMockRecorder) UpdateUserAgentChatSendShortcut(ctx, arg any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "UpdateUserAgentChatSendShortcut", reflect.TypeOf((*MockStore)(nil).UpdateUserAgentChatSendShortcut), ctx, arg)
+}
+
 // UpdateUserChatCompactionThreshold mocks base method.
 func (m *MockStore) UpdateUserChatCompactionThreshold(ctx context.Context, arg database.UpdateUserChatCompactionThresholdParams) (database.UserConfig, error) {
 	m.ctrl.T.Helper()

coderd/database/querier.go

@@ -699,6 +699,7 @@ type sqlcQuerier interface {
 	// produces a bloated value if a user has used multiple templates
 	// simultaneously.
 	GetUserActivityInsights(ctx context.Context, arg GetUserActivityInsightsParams) ([]GetUserActivityInsightsRow, error)
+	GetUserAgentChatSendShortcut(ctx context.Context, userID uuid.UUID) (string, error)
 	GetUserByEmailOrUsername(ctx context.Context, arg GetUserByEmailOrUsernameParams) (User, error)
 	GetUserByID(ctx context.Context, id uuid.UUID) (User, error)
 	GetUserChatCompactionThreshold(ctx context.Context, arg GetUserChatCompactionThresholdParams) (string, error)
@@ -1195,6 +1196,7 @@ type sqlcQuerier interface {
 	UpdateTemplateVersionFlagsByJobID(ctx context.Context, arg UpdateTemplateVersionFlagsByJobIDParams) error
 	UpdateTemplateWorkspacesLastUsedAt(ctx context.Context, arg UpdateTemplateWorkspacesLastUsedAtParams) error
 	UpdateUsageEventsPostPublish(ctx context.Context, arg UpdateUsageEventsPostPublishParams) error
+	UpdateUserAgentChatSendShortcut(ctx context.Context, arg UpdateUserAgentChatSendShortcutParams) (string, error)
 	UpdateUserChatCompactionThreshold(ctx context.Context, arg UpdateUserChatCompactionThresholdParams) (UserConfig, error)
 	UpdateUserChatCustomPrompt(ctx context.Context, arg UpdateUserChatCustomPromptParams) (UserConfig, error)
 	UpdateUserChatProviderKey(ctx context.Context, arg UpdateUserChatProviderKeyParams) (UserChatProviderKey, error)

coderd/database/queries.sql.go

@@ -25607,6 +25607,23 @@ func (q *sqlQuerier) GetAuthorizationUserRoles(ctx context.Context, userID uuid.
 	return i, err
 }
 
+const getUserAgentChatSendShortcut = `-- name: GetUserAgentChatSendShortcut :one
+SELECT
+	value AS agent_chat_send_shortcut
+FROM
+	user_configs
+WHERE
+	user_id = $1
+	AND key = 'preference_agent_chat_send_shortcut'
+`
+
+func (q *sqlQuerier) GetUserAgentChatSendShortcut(ctx context.Context, userID uuid.UUID) (string, error) {
+	row := q.db.QueryRowContext(ctx, getUserAgentChatSendShortcut, userID)
+	var agent_chat_send_shortcut string
+	err := row.Scan(&agent_chat_send_shortcut)
+	return agent_chat_send_shortcut, err
+}
+
 const getUserByEmailOrUsername = `-- name: GetUserByEmailOrUsername :one
 SELECT
 	id, email, username, hashed_password, created_at, updated_at, status, rbac_roles, login_type, avatar_url, deleted, last_seen_at, quiet_hours_schedule, name, github_com_user_id, hashed_one_time_passcode, one_time_passcode_expires_at, is_system, is_service_account, chat_spend_limit_micros
@@ -26327,6 +26344,33 @@ func (q *sqlQuerier) UpdateInactiveUsersToDormant(ctx context.Context, arg Updat
 	return items, nil
 }
 
+const updateUserAgentChatSendShortcut = `-- name: UpdateUserAgentChatSendShortcut :one
+INSERT INTO
+	user_configs (user_id, key, value)
+VALUES
+	($1, 'preference_agent_chat_send_shortcut', $2::text)
+ON CONFLICT
+	ON CONSTRAINT user_configs_pkey
+DO UPDATE
+SET
+	value = $2
+WHERE user_configs.user_id = $1
+	AND user_configs.key = 'preference_agent_chat_send_shortcut'
+RETURNING value AS agent_chat_send_shortcut
+`
+
+type UpdateUserAgentChatSendShortcutParams struct {
+	UserID                uuid.UUID `db:"user_id" json:"user_id"`
+	AgentChatSendShortcut string    `db:"agent_chat_send_shortcut" json:"agent_chat_send_shortcut"`
+}
+
+func (q *sqlQuerier) UpdateUserAgentChatSendShortcut(ctx context.Context, arg UpdateUserAgentChatSendShortcutParams) (string, error) {
+	row := q.db.QueryRowContext(ctx, updateUserAgentChatSendShortcut, arg.UserID, arg.AgentChatSendShortcut)
+	var agent_chat_send_shortcut string
+	err := row.Scan(&agent_chat_send_shortcut)
+	return agent_chat_send_shortcut, err
+}
+
 const updateUserChatCompactionThreshold = `-- name: UpdateUserChatCompactionThreshold :one
 INSERT INTO user_configs (user_id, key, value)
 VALUES ($1, $2, ($3::int)::text)

coderd/database/queries/users.sql

@@ -327,6 +327,29 @@ WHERE user_configs.user_id = @user_id
 	AND user_configs.key = 'preference_code_diff_display_mode'
 RETURNING value AS code_diff_display_mode;
 
+-- name: GetUserAgentChatSendShortcut :one
+SELECT
+	value AS agent_chat_send_shortcut
+FROM
+	user_configs
+WHERE
+	user_id = @user_id
+	AND key = 'preference_agent_chat_send_shortcut';
+
+-- name: UpdateUserAgentChatSendShortcut :one
+INSERT INTO
+	user_configs (user_id, key, value)
+VALUES
+	(@user_id, 'preference_agent_chat_send_shortcut', @agent_chat_send_shortcut::text)
+ON CONFLICT
+	ON CONSTRAINT user_configs_pkey
+DO UPDATE
+SET
+	value = @agent_chat_send_shortcut
+WHERE user_configs.user_id = @user_id
+	AND user_configs.key = 'preference_agent_chat_send_shortcut'
+RETURNING value AS agent_chat_send_shortcut;
+
 -- name: UpdateUserRoles :one
 UPDATE
 	users

coderd/users.go

@@ -1257,10 +1257,20 @@ func (api *API) userPreferenceSettings(rw http.ResponseWriter, r *http.Request)
 		return
 	}
 
+	agentChatSendShortcut, err := api.Database.GetUserAgentChatSendShortcut(ctx, user.ID)
+	if err != nil && !errors.Is(err, sql.ErrNoRows) {
+		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+			Message: "Error reading user preference settings.",
+			Detail:  err.Error(),
+		})
+		return
+	}
+
 	httpapi.Write(ctx, rw, http.StatusOK, codersdk.UserPreferenceSettings{
 		TaskNotificationAlertDismissed: taskAlertDismissed,
 		ThinkingDisplayMode:            sanitizeThinkingDisplayMode(thinkingMode),
 		CodeDiffDisplayMode:            sanitizeAgentDisplayMode(codeDiffMode),
+		AgentChatSendShortcut:          sanitizeAgentChatSendShortcut(agentChatSendShortcut),
 	})
 }
 
@@ -1305,6 +1315,16 @@ func (api *API) putUserPreferenceSettings(rw http.ResponseWriter, r *http.Reques
 		})
 		return
 	}
+	if params.AgentChatSendShortcut != "" &&
+		!slices.Contains(codersdk.ValidAgentChatSendShortcuts, params.AgentChatSendShortcut) {
+		httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
+			Message: "Invalid agent chat send shortcut.",
+			Validations: []codersdk.ValidationError{
+				{Field: "agent_chat_send_shortcut", Detail: agentChatSendShortcutValidationDetail},
+			},
+		})
+		return
+	}
 	var settings codersdk.UserPreferenceSettings
 	err := api.Database.InTx(func(tx database.Store) error {
 		var err error
@@ -1356,6 +1376,23 @@ func (api *API) putUserPreferenceSettings(rw http.ResponseWriter, r *http.Reques
 			}
 			settings.CodeDiffDisplayMode = sanitizeAgentDisplayMode(stored)
 		}
+
+		if params.AgentChatSendShortcut != "" {
+			updated, err := tx.UpdateUserAgentChatSendShortcut(ctx, database.UpdateUserAgentChatSendShortcutParams{
+				UserID:                user.ID,
+				AgentChatSendShortcut: string(params.AgentChatSendShortcut),
+			})
+			if err != nil {
+				return newUserPreferenceSettingsAPIError("Internal error updating agent chat send shortcut.", err)
+			}
+			settings.AgentChatSendShortcut = sanitizeAgentChatSendShortcut(updated)
+		} else {
+			stored, err := tx.GetUserAgentChatSendShortcut(ctx, user.ID)
+			if err != nil && !errors.Is(err, sql.ErrNoRows) {
+				return newUserPreferenceSettingsAPIError("Error reading agent chat send shortcut.", err)
+			}
+			settings.AgentChatSendShortcut = sanitizeAgentChatSendShortcut(stored)
+		}
 		return nil
 	}, database.DefaultTXOptions().WithID("user_preference_settings"))
 	if err != nil {
@@ -1400,8 +1437,9 @@ func (e userPreferenceSettingsAPIError) Unwrap() error {
 }
 
 const (
-	thinkingDisplayModeValidationDetail = "must be one of: auto, preview, always_expanded, always_collapsed"
-	agentDisplayModeValidationDetail    = "must be one of: auto, always_expanded, always_collapsed"
+	thinkingDisplayModeValidationDetail   = "must be one of: auto, preview, always_expanded, always_collapsed"
+	agentDisplayModeValidationDetail      = "must be one of: auto, always_expanded, always_collapsed"
+	agentChatSendShortcutValidationDetail = "must be one of: enter, modifier_enter"
 )
 
 func sanitizeThinkingDisplayMode(raw string) codersdk.ThinkingDisplayMode {
@@ -1420,6 +1458,14 @@ func sanitizeAgentDisplayMode(raw string) codersdk.AgentDisplayMode {
 	return codersdk.AgentDisplayModeAuto
 }
 
+func sanitizeAgentChatSendShortcut(raw string) codersdk.AgentChatSendShortcut {
+	shortcut := codersdk.AgentChatSendShortcut(raw)
+	if slices.Contains(codersdk.ValidAgentChatSendShortcuts, shortcut) {
+		return shortcut
+	}
+	return codersdk.AgentChatSendShortcutEnter
+}
+
 func isValidFontName(font codersdk.TerminalFontName) bool {
 	return slices.Contains(codersdk.TerminalFontNames, font)
 }

coderd/users_test.go

@@ -1963,6 +1963,91 @@ func TestThinkingDisplayMode(t *testing.T) {
 	})
 }
 
+func TestAgentChatSendShortcutPreference(t *testing.T) {
+	t.Parallel()
+
+	adminClient := coderdtest.New(t, nil)
+	firstUser := coderdtest.CreateFirstUser(t, adminClient)
+
+	requireValidationField := func(t *testing.T, err error, field string) {
+		t.Helper()
+
+		var sdkErr *codersdk.Error
+		require.ErrorAs(t, err, &sdkErr)
+		require.Equal(t, http.StatusBadRequest, sdkErr.StatusCode())
+		require.Len(t, sdkErr.Validations, 1)
+		require.Equal(t, field, sdkErr.Validations[0].Field)
+	}
+
+	t.Run("defaults to enter", func(t *testing.T) {
+		t.Parallel()
+
+		client, _ := coderdtest.CreateAnotherUser(t, adminClient, firstUser.OrganizationID)
+
+		ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
+		defer cancel()
+
+		settings, err := client.GetUserPreferenceSettings(ctx, codersdk.Me)
+		require.NoError(t, err)
+		require.Equal(t, codersdk.AgentChatSendShortcutEnter, settings.AgentChatSendShortcut)
+	})
+
+	t.Run("round-trips shortcut", func(t *testing.T) {
+		t.Parallel()
+
+		client, _ := coderdtest.CreateAnotherUser(t, adminClient, firstUser.OrganizationID)
+
+		ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
+		defer cancel()
+
+		updated, err := client.UpdateUserPreferenceSettings(ctx, codersdk.Me, codersdk.UpdateUserPreferenceSettingsRequest{
+			AgentChatSendShortcut: codersdk.AgentChatSendShortcutModifierEnter,
+		})
+		require.NoError(t, err)
+		require.Equal(t, codersdk.AgentChatSendShortcutModifierEnter, updated.AgentChatSendShortcut)
+
+		settings, err := client.GetUserPreferenceSettings(ctx, codersdk.Me)
+		require.NoError(t, err)
+		require.Equal(t, codersdk.AgentChatSendShortcutModifierEnter, settings.AgentChatSendShortcut)
+	})
+
+	t.Run("rejects invalid shortcut", func(t *testing.T) {
+		t.Parallel()
+
+		client, _ := coderdtest.CreateAnotherUser(t, adminClient, firstUser.OrganizationID)
+
+		ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
+		defer cancel()
+
+		_, err := client.UpdateUserPreferenceSettings(ctx, codersdk.Me, codersdk.UpdateUserPreferenceSettingsRequest{
+			AgentChatSendShortcut: codersdk.AgentChatSendShortcut("bogus"),
+		})
+		requireValidationField(t, err, "agent_chat_send_shortcut")
+	})
+
+	t.Run("updates preserve stored shortcut", func(t *testing.T) {
+		t.Parallel()
+
+		client, _ := coderdtest.CreateAnotherUser(t, adminClient, firstUser.OrganizationID)
+
+		ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
+		defer cancel()
+
+		_, err := client.UpdateUserPreferenceSettings(ctx, codersdk.Me, codersdk.UpdateUserPreferenceSettingsRequest{
+			AgentChatSendShortcut: codersdk.AgentChatSendShortcutModifierEnter,
+			ThinkingDisplayMode:   codersdk.ThinkingDisplayModePreview,
+		})
+		require.NoError(t, err)
+
+		updated, err := client.UpdateUserPreferenceSettings(ctx, codersdk.Me, codersdk.UpdateUserPreferenceSettingsRequest{
+			ThinkingDisplayMode: codersdk.ThinkingDisplayModeAlwaysExpanded,
+		})
+		require.NoError(t, err)
+		require.Equal(t, codersdk.ThinkingDisplayModeAlwaysExpanded, updated.ThinkingDisplayMode)
+		require.Equal(t, codersdk.AgentChatSendShortcutModifierEnter, updated.AgentChatSendShortcut)
+	})
+}
+
 func TestAgentDisplayModePreferences(t *testing.T) {
 	t.Parallel()
 

codersdk/users.go

@@ -263,15 +263,29 @@ type UpdateUserAppearanceSettingsRequest struct {
 }
 
 type UserPreferenceSettings struct {
-	TaskNotificationAlertDismissed bool                `json:"task_notification_alert_dismissed"`
-	ThinkingDisplayMode            ThinkingDisplayMode `json:"thinking_display_mode"`
-	CodeDiffDisplayMode            AgentDisplayMode    `json:"code_diff_display_mode"`
+	TaskNotificationAlertDismissed bool                  `json:"task_notification_alert_dismissed"`
+	ThinkingDisplayMode            ThinkingDisplayMode   `json:"thinking_display_mode"`
+	CodeDiffDisplayMode            AgentDisplayMode      `json:"code_diff_display_mode"`
+	AgentChatSendShortcut          AgentChatSendShortcut `json:"agent_chat_send_shortcut"`
 }
 
 type UpdateUserPreferenceSettingsRequest struct {
-	TaskNotificationAlertDismissed *bool               `json:"task_notification_alert_dismissed,omitempty"`
-	ThinkingDisplayMode            ThinkingDisplayMode `json:"thinking_display_mode,omitempty"`
-	CodeDiffDisplayMode            AgentDisplayMode    `json:"code_diff_display_mode,omitempty"`
+	TaskNotificationAlertDismissed *bool                 `json:"task_notification_alert_dismissed,omitempty"`
+	ThinkingDisplayMode            ThinkingDisplayMode   `json:"thinking_display_mode,omitempty"`
+	CodeDiffDisplayMode            AgentDisplayMode      `json:"code_diff_display_mode,omitempty"`
+	AgentChatSendShortcut          AgentChatSendShortcut `json:"agent_chat_send_shortcut,omitempty"`
+}
+
+type AgentChatSendShortcut string
+
+const (
+	AgentChatSendShortcutEnter         AgentChatSendShortcut = "enter"
+	AgentChatSendShortcutModifierEnter AgentChatSendShortcut = "modifier_enter"
+)
+
+var ValidAgentChatSendShortcuts = []AgentChatSendShortcut{
+	AgentChatSendShortcutEnter,
+	AgentChatSendShortcutModifierEnter,
 }
 
 type ThinkingDisplayMode string

docs/reference/api/schemas.md

@@ -1412,6 +1412,20 @@
 |-----------|--------|----------|--------------|-------------|
 | `license` | string | true     |              |             |
 
+## codersdk.AgentChatSendShortcut
+
+```json
+"enter"
+```
+
+### Properties
+
+#### Enumerated Values
+
+| Value(s)                  |
+|---------------------------|
+| `enter`, `modifier_enter` |
+
 ## codersdk.AgentConnectionTiming
 
 ```json
@@ -12867,6 +12881,7 @@ Restarts will only happen on weekdays in this list on weeks which line up with W
 
 ```json
 {
+  "agent_chat_send_shortcut": "enter",
   "code_diff_display_mode": "auto",
   "task_notification_alert_dismissed": true,
   "thinking_display_mode": "auto"
@@ -12875,11 +12890,12 @@ Restarts will only happen on weekdays in this list on weeks which line up with W
 
 ### Properties
 
-| Name                                | Type                                                         | Required | Restrictions | Description |
-|-------------------------------------|--------------------------------------------------------------|----------|--------------|-------------|
-| `code_diff_display_mode`            | [codersdk.AgentDisplayMode](#codersdkagentdisplaymode)       | false    |              |             |
-| `task_notification_alert_dismissed` | boolean                                                      | false    |              |             |
-| `thinking_display_mode`             | [codersdk.ThinkingDisplayMode](#codersdkthinkingdisplaymode) | false    |              |             |
+| Name                                | Type                                                             | Required | Restrictions | Description |
+|-------------------------------------|------------------------------------------------------------------|----------|--------------|-------------|
+| `agent_chat_send_shortcut`          | [codersdk.AgentChatSendShortcut](#codersdkagentchatsendshortcut) | false    |              |             |
+| `code_diff_display_mode`            | [codersdk.AgentDisplayMode](#codersdkagentdisplaymode)           | false    |              |             |
+| `task_notification_alert_dismissed` | boolean                                                          | false    |              |             |
+| `thinking_display_mode`             | [codersdk.ThinkingDisplayMode](#codersdkthinkingdisplaymode)     | false    |              |             |
 
 ## codersdk.UpdateUserProfileRequest
 
@@ -13455,6 +13471,7 @@ If the schedule is empty, the user will be updated to use the default schedule.|
 
 ```json
 {
+  "agent_chat_send_shortcut": "enter",
   "code_diff_display_mode": "auto",
   "task_notification_alert_dismissed": true,
   "thinking_display_mode": "auto"
@@ -13463,11 +13480,12 @@ If the schedule is empty, the user will be updated to use the default schedule.|
 
 ### Properties
 
-| Name                                | Type                                                         | Required | Restrictions | Description |
-|-------------------------------------|--------------------------------------------------------------|----------|--------------|-------------|
-| `code_diff_display_mode`            | [codersdk.AgentDisplayMode](#codersdkagentdisplaymode)       | false    |              |             |
-| `task_notification_alert_dismissed` | boolean                                                      | false    |              |             |
-| `thinking_display_mode`             | [codersdk.ThinkingDisplayMode](#codersdkthinkingdisplaymode) | false    |              |             |
+| Name                                | Type                                                             | Required | Restrictions | Description |
+|-------------------------------------|------------------------------------------------------------------|----------|--------------|-------------|
+| `agent_chat_send_shortcut`          | [codersdk.AgentChatSendShortcut](#codersdkagentchatsendshortcut) | false    |              |             |
+| `code_diff_display_mode`            | [codersdk.AgentDisplayMode](#codersdkagentdisplaymode)           | false    |              |             |
+| `task_notification_alert_dismissed` | boolean                                                          | false    |              |             |
+| `thinking_display_mode`             | [codersdk.ThinkingDisplayMode](#codersdkthinkingdisplaymode)     | false    |              |             |
 
 ## codersdk.UserQuietHoursScheduleConfig
 

docs/reference/api/users.md

@@ -1301,6 +1301,7 @@ curl -X GET http://coder-server:8080/api/v2/users/{user}/preferences \
 
 ```json
 {
+  "agent_chat_send_shortcut": "enter",
   "code_diff_display_mode": "auto",
   "task_notification_alert_dismissed": true,
   "thinking_display_mode": "auto"
@@ -1333,6 +1334,7 @@ curl -X PUT http://coder-server:8080/api/v2/users/{user}/preferences \
 
 ```json
 {
+  "agent_chat_send_shortcut": "enter",
   "code_diff_display_mode": "auto",
   "task_notification_alert_dismissed": true,
   "thinking_display_mode": "auto"
@@ -1352,6 +1354,7 @@ curl -X PUT http://coder-server:8080/api/v2/users/{user}/preferences \
 
 ```json
 {
+  "agent_chat_send_shortcut": "enter",
   "code_diff_display_mode": "auto",
   "task_notification_alert_dismissed": true,
   "thinking_display_mode": "auto"

site/src/api/typesGenerated.ts

@@ -837,6 +837,14 @@ export interface AdvisorConfig {
 	readonly model_config_id: string;
 }
 
+// From codersdk/users.go
+export type AgentChatSendShortcut = "enter" | "modifier_enter";
+
+export const AgentChatSendShortcuts: AgentChatSendShortcut[] = [
+	"enter",
+	"modifier_enter",
+];
+
 // From codersdk/workspacebuilds.go
 export interface AgentConnectionTiming {
 	readonly started_at: string;
@@ -8392,6 +8400,7 @@ export interface UpdateUserPreferenceSettingsRequest {
 	readonly task_notification_alert_dismissed?: boolean;
 	readonly thinking_display_mode?: ThinkingDisplayMode;
 	readonly code_diff_display_mode?: AgentDisplayMode;
+	readonly agent_chat_send_shortcut?: AgentChatSendShortcut;
 }
 
 // From codersdk/users.go
@@ -8770,6 +8779,7 @@ export interface UserPreferenceSettings {
 	readonly task_notification_alert_dismissed: boolean;
 	readonly thinking_display_mode: ThinkingDisplayMode;
 	readonly code_diff_display_mode: AgentDisplayMode;
+	readonly agent_chat_send_shortcut: AgentChatSendShortcut;
 }
 
 // From codersdk/deployment.go

site/src/pages/AgentsPage/AgentChatPage.tsx

@@ -37,7 +37,7 @@ import {
 	userCompactionThresholds,
 } from "#/api/queries/chats";
 import { deploymentSSHConfig } from "#/api/queries/deployment";
-import { user as userQuery } from "#/api/queries/users";
+import { preferenceSettings, user as userQuery } from "#/api/queries/users";
 import {
 	workspaceById,
 	workspaceByIdKey,
@@ -80,6 +80,7 @@ import {
 } from "./components/MCPServerPicker";
 import { getModelSelectorHelp } from "./components/ModelSelectorHelp";
 import { useGitWatcher } from "./hooks/useGitWatcher";
+import { getAgentChatSendShortcut } from "./utils/agentChatSendShortcut";
 import { type ParsedDraft, parseStoredDraft } from "./utils/draftStorage";
 import {
 	countConfiguredProviderConfigs,
@@ -768,6 +769,7 @@ const AgentChatPage: FC = () => {
 		enabled: permissions.editDeploymentConfig,
 	});
 	const userThresholdsQuery = useQuery(userCompactionThresholds());
+	const preferencesQuery = useQuery(preferenceSettings());
 	const desktopEnabledQuery = useQuery(chatDesktopEnabled());
 	const userDebugLoggingQuery = useQuery(userChatDebugLogging());
 	const mcpServersQuery = useQuery(mcpServerConfigs());
@@ -1507,6 +1509,10 @@ const AgentChatPage: FC = () => {
 	if (chatQuery.isLoading || chatMessagesQuery.isLoading) {
 		return (
 			<AgentChatPageLoadingView
+				sendShortcut={getAgentChatSendShortcut(
+					preferencesQuery.data?.agent_chat_send_shortcut,
+					preferencesQuery.isLoading,
+				)}
 				titleElement={titleElement}
 				isInputDisabled={isInputDisabled}
 				effectiveSelectedModel={effectiveSelectedModel}
@@ -1537,6 +1543,10 @@ const AgentChatPage: FC = () => {
 	return (
 		<AgentChatPageView
 			agentId={agentId}
+			sendShortcut={getAgentChatSendShortcut(
+				preferencesQuery.data?.agent_chat_send_shortcut,
+				preferencesQuery.isLoading,
+			)}
 			organizationId={chatQuery.data?.organization_id}
 			chatTitle={chatTitle}
 			parentChat={parentChat}

site/src/pages/AgentsPage/AgentChatPageView.stories.tsx

@@ -132,6 +132,7 @@ const StoryAgentChatPageView: FC<StoryProps> = ({ editing, ...overrides }) => {
 
 	const props = {
 		agentId: AGENT_ID,
+		sendShortcut: "enter" as const,
 		organizationId: "test-org-id",
 		chatTitle: "Help me refactor",
 		persistedError: undefined as ChatDetailError | undefined,
@@ -620,6 +621,7 @@ export const WorkspaceNoAgent: Story = {
 export const Loading: Story = {
 	render: () => (
 		<AgentChatPageLoadingView
+			sendShortcut="enter"
 			titleElement={<title>Loading — Agents</title>}
 			isInputDisabled
 			effectiveSelectedModel={defaultModelConfigID}
@@ -638,6 +640,7 @@ export const Loading: Story = {
 export const LoadingWithModelOptions: Story = {
 	render: () => (
 		<AgentChatPageLoadingView
+			sendShortcut="enter"
 			titleElement={<title>Loading — Agents</title>}
 			isInputDisabled={false}
 			effectiveSelectedModel={defaultModelConfigID}
@@ -655,6 +658,7 @@ export const LoadingWithModelOptions: Story = {
 export const LoadingWithRightPanel: Story = {
 	render: () => (
 		<AgentChatPageLoadingView
+			sendShortcut="enter"
 			titleElement={<title>Loading — Agents</title>}
 			isInputDisabled
 			effectiveSelectedModel={defaultModelConfigID}
@@ -673,6 +677,7 @@ export const LoadingWithRightPanel: Story = {
 export const LoadingSidebarCollapsed: Story = {
 	render: () => (
 		<AgentChatPageLoadingView
+			sendShortcut="enter"
 			titleElement={<title>Loading — Agents</title>}
 			isInputDisabled
 			effectiveSelectedModel={defaultModelConfigID}

site/src/pages/AgentsPage/AgentChatPageView.tsx

@@ -11,7 +11,11 @@ import { useQueryClient } from "react-query";
 import type { UrlTransform } from "streamdown";
 import { chatDiffContentsKey } from "#/api/queries/chats";
 import type * as TypesGen from "#/api/typesGenerated";
-import type { ChatDiffStatus, ChatMessagePart } from "#/api/typesGenerated";
+import type {
+	AgentChatSendShortcut,
+	ChatDiffStatus,
+	ChatMessagePart,
+} from "#/api/typesGenerated";
 import { cn } from "#/utils/cn";
 import { pageTitle } from "#/utils/page";
 import {
@@ -82,6 +86,7 @@ interface EditingState {
 interface AgentChatPageViewProps {
 	// Chat data.
 	agentId: string;
+	sendShortcut: AgentChatSendShortcut;
 	organizationId: string | undefined;
 	chatTitle: string | undefined;
 	parentChat: TypesGen.Chat | undefined;
@@ -185,6 +190,7 @@ interface AgentChatPageViewProps {
 
 export const AgentChatPageView: FC<AgentChatPageViewProps> = ({
 	agentId,
+	sendShortcut,
 	organizationId,
 	chatTitle,
 	parentChat,
@@ -521,6 +527,7 @@ export const AgentChatPageView: FC<AgentChatPageViewProps> = ({
 						<div className="shrink-0 overflow-y-auto px-4 pb-3 md:pb-0 [scrollbar-gutter:stable] [scrollbar-width:thin]">
 							<ChatPageInput
 								organizationId={organizationId}
+								sendShortcut={sendShortcut}
 								store={store}
 								compressionThreshold={compressionThreshold}
 								onSend={editing.handleSendFromInput}
@@ -600,6 +607,7 @@ export const AgentChatPageView: FC<AgentChatPageViewProps> = ({
 };
 
 interface AgentChatPageLoadingViewProps {
+	sendShortcut: AgentChatSendShortcut;
 	titleElement: React.ReactNode;
 	isInputDisabled: boolean;
 	effectiveSelectedModel: string;
@@ -616,6 +624,7 @@ interface AgentChatPageLoadingViewProps {
 }
 
 export const AgentChatPageLoadingView: FC<AgentChatPageLoadingViewProps> = ({
+	sendShortcut,
 	titleElement,
 	isInputDisabled,
 	effectiveSelectedModel,
@@ -668,6 +677,7 @@ export const AgentChatPageLoadingView: FC<AgentChatPageLoadingViewProps> = ({
 				<div className="shrink-0 overflow-y-auto px-4 pb-3 md:pb-0 [scrollbar-gutter:stable] [scrollbar-width:thin]">
 					<AgentChatInput
 						onSend={() => {}}
+						sendShortcut={sendShortcut}
 						initialValue=""
 						isDisabled={isInputDisabled}
 						isLoading={false}

site/src/pages/AgentsPage/AgentCreatePage.tsx

@@ -11,6 +11,7 @@ import {
 	mcpServerConfigs,
 	userChatPersonalModelOverrides,
 } from "#/api/queries/chats";
+import { preferenceSettings } from "#/api/queries/users";
 import { workspaces } from "#/api/queries/workspaces";
 import type * as TypesGen from "#/api/typesGenerated";
 import { useWebpushNotifications } from "#/contexts/useWebpushNotifications";
@@ -23,6 +24,7 @@ import { AgentPageHeader } from "./components/AgentPageHeader";
 import { AgentSetupNotice } from "./components/AgentSetupNotice";
 import { ChimeButton } from "./components/ChimeButton";
 import { WebPushButton } from "./components/WebPushButton";
+import { getAgentChatSendShortcut } from "./utils/agentChatSendShortcut";
 import { getChimeEnabled, setChimeEnabled } from "./utils/chime";
 import {
 	countConfiguredProviderConfigs,
@@ -46,6 +48,7 @@ const AgentCreatePage: FC = () => {
 	const personalModelOverridesQuery = useQuery(
 		userChatPersonalModelOverrides(),
 	);
+	const preferencesQuery = useQuery(preferenceSettings());
 	const mcpServersQuery = useQuery(mcpServerConfigs());
 	const workspacesQuery = useQuery(workspaces({ q: "owner:me", limit: 0 }));
 	const createMutation = useMutation(createChat(queryClient));
@@ -148,6 +151,10 @@ const AgentCreatePage: FC = () => {
 			</AgentPageHeader>
 			<AgentCreateForm
 				onCreateChat={handleCreateChat}
+				sendShortcut={getAgentChatSendShortcut(
+					preferencesQuery.data?.agent_chat_send_shortcut,
+					preferencesQuery.isLoading,
+				)}
 				isCreating={createMutation.isPending}
 				createError={createMutation.error}
 				canCreateChat={permissions.createChat}

site/src/pages/AgentsPage/AgentSettingsGeneralPageView.stories.tsx

@@ -1,10 +1,19 @@
 import type { Meta, StoryObj } from "@storybook/react-vite";
-import { expect, fn, userEvent, waitFor, within } from "storybook/test";
+import { expect, fn, spyOn, userEvent, waitFor, within } from "storybook/test";
+import { API } from "#/api/api";
+import type { AgentChatSendShortcut } from "#/api/typesGenerated";
 import {
 	AgentSettingsGeneralPageView,
 	type AgentSettingsGeneralPageViewProps,
 } from "./AgentSettingsGeneralPageView";
 
+const preferencesData = {
+	task_notification_alert_dismissed: false,
+	thinking_display_mode: "auto" as const,
+	code_diff_display_mode: "auto" as const,
+	agent_chat_send_shortcut: "enter" as const,
+};
+
 const baseArgs: AgentSettingsGeneralPageViewProps = {
 	userPromptData: {
 		custom_prompt: "Prefer concise answers with clear next steps.",
@@ -26,6 +35,9 @@ const meta = {
 	title: "pages/AgentsPage/AgentSettingsGeneralPageView",
 	component: AgentSettingsGeneralPageView,
 	args: baseArgs,
+	parameters: {
+		queries: [{ key: ["me", "preferences"], data: preferencesData }],
+	},
 } satisfies Meta<typeof AgentSettingsGeneralPageView>;
 
 export default meta;
@@ -122,19 +134,45 @@ export const RendersChatLayoutSection: Story = {
 	},
 };
 
-export const RendersAgentDisplayModeSettings: Story = {
-	parameters: {
-		queries: [
-			{
-				key: ["me", "preferences"],
-				data: {
-					task_notification_alert_dismissed: false,
-					thinking_display_mode: "auto" as const,
-					code_diff_display_mode: "auto" as const,
-				},
+export const TogglesSendShortcut: Story = {
+	beforeEach: () => {
+		let agentChatSendShortcut: AgentChatSendShortcut =
+			preferencesData.agent_chat_send_shortcut;
+		spyOn(API, "getUserPreferenceSettings").mockImplementation(async () => ({
+			...preferencesData,
+			agent_chat_send_shortcut: agentChatSendShortcut,
+		}));
+		spyOn(API, "updateUserPreferenceSettings").mockImplementation(
+			async (req) => {
+				agentChatSendShortcut =
+					req.agent_chat_send_shortcut ?? agentChatSendShortcut;
+				return {
+					...preferencesData,
+					agent_chat_send_shortcut: agentChatSendShortcut,
+				};
 			},
-		],
+		);
 	},
+	play: async ({ canvasElement }) => {
+		const canvas = within(canvasElement);
+		const toggle = await canvas.findByRole("switch", {
+			name: "Require Cmd/Ctrl+Enter to send messages",
+		});
+
+		expect(await canvas.findByText("Keyboard Shortcuts")).toBeInTheDocument();
+		expect(toggle).not.toBeChecked();
+
+		await userEvent.click(toggle);
+		await waitFor(() => {
+			expect(API.updateUserPreferenceSettings).toHaveBeenCalledWith({
+				agent_chat_send_shortcut: "modifier_enter",
+			});
+			expect(toggle).toBeChecked();
+		});
+	},
+};
+
+export const RendersAgentDisplayModeSettings: Story = {
 	play: async ({ canvasElement }) => {
 		const canvas = within(canvasElement);
 

site/src/pages/AgentsPage/AgentSettingsGeneralPageView.tsx

@@ -2,6 +2,7 @@ import type { FC } from "react";
 import type { UseMutateFunction } from "react-query";
 import type * as TypesGen from "#/api/typesGenerated";
 import { ChatFullWidthSettings } from "./components/ChatFullWidthSettings";
+import { ChatSendShortcutSettings } from "./components/ChatSendShortcutSettings";
 import {
 	CodeDiffDisplaySettings,
 	ThinkingDisplaySettings,
@@ -57,6 +58,7 @@ export const AgentSettingsGeneralPageView: FC<
 				isAnyPromptSaving={isSavingUserPrompt}
 			/>
 			<ChatFullWidthSettings />
+			<ChatSendShortcutSettings />
 			<ThinkingDisplaySettings />
 			<CodeDiffDisplaySettings />
 			<UserChatDebugLoggingSettings

site/src/pages/AgentsPage/components/AgentChatInput.stories.tsx

@@ -29,6 +29,7 @@ const meta: Meta<typeof AgentChatInput> = {
 	decorators: [withProxyProvider()],
 	args: {
 		onSend: fn(),
+		sendShortcut: "enter",
 		onContentChange: fn(),
 		onModelChange: fn(),
 		initialValue: "",
@@ -210,6 +211,54 @@ export const SendsAndClearsInput: Story = {
 	},
 };
 
+export const EnterSendsByDefault: Story = {
+	args: {
+		onSend: fn(),
+		initialValue: "Run focused tests",
+	},
+	play: async ({ canvasElement, args }) => {
+		const canvas = within(canvasElement);
+		const editor = canvas.getByTestId("chat-message-input");
+		await waitFor(() => {
+			expect(editor.textContent).toBe("Run focused tests");
+		});
+
+		await userEvent.click(editor);
+		await userEvent.keyboard("{Enter}");
+
+		await waitFor(() => {
+			expect(args.onSend).toHaveBeenCalledWith("Run focused tests");
+		});
+	},
+};
+
+export const ModifierEnterSendsWhenRequired: Story = {
+	args: {
+		onSend: fn(),
+		sendShortcut: "modifier_enter",
+		initialValue: "Run focused tests",
+	},
+	play: async ({ canvasElement, args }) => {
+		const canvas = within(canvasElement);
+		const editor = canvas.getByTestId("chat-message-input");
+		await waitFor(() => {
+			expect(editor.textContent).toBe("Run focused tests");
+		});
+
+		await userEvent.click(editor);
+		await userEvent.keyboard("{Enter}");
+		expect(args.onSend).not.toHaveBeenCalled();
+		await waitFor(() => {
+			expect(editor.querySelectorAll("br").length).toBeGreaterThan(0);
+		});
+
+		await userEvent.keyboard("{Control>}{Enter}{/Control}");
+		await waitFor(() => {
+			expect(args.onSend).toHaveBeenCalledWith("Run focused tests");
+		});
+	},
+};
+
 /**
  * CODAGT-210: On mobile viewports, Enter must insert a newline rather
  * than submit the message, because Shift+Enter is cumbersome on

site/src/pages/AgentsPage/components/AgentChatInput.tsx

@@ -22,7 +22,11 @@ import {
 } from "react";
 import { Link } from "react-router";
 import type * as TypesGen from "#/api/typesGenerated";
-import type { ChatMessagePart, ChatQueuedMessage } from "#/api/typesGenerated";
+import type {
+	AgentChatSendShortcut,
+	ChatMessagePart,
+	ChatQueuedMessage,
+} from "#/api/typesGenerated";
 import { Alert, AlertDescription } from "#/components/Alert/Alert";
 import { Button } from "#/components/Button/Button";
 import {
@@ -54,6 +58,10 @@ import { isBelowMdViewport, isMobileViewport } from "#/utils/mobile";
 import { chatWidthClass, useChatFullWidth } from "../hooks/useChatFullWidth";
 import { useOverflowCount } from "../hooks/useOverflowCount";
 import { useSpeechRecognition } from "../hooks/useSpeechRecognition";
+import {
+	DEFAULT_AGENT_CHAT_SEND_SHORTCUT,
+	MODIFIER_AGENT_CHAT_SEND_SHORTCUT,
+} from "../utils/agentChatSendShortcut";
 import {
 	chatAttachmentAcceptAttribute,
 	isChatAttachmentFile,
@@ -86,6 +94,7 @@ export type { AgentContextUsage } from "./ContextUsageIndicator";
 
 interface AgentChatInputProps {
 	onSend: (message: string) => void;
+	sendShortcut?: AgentChatSendShortcut;
 	placeholder?: string;
 	isDisabled: boolean;
 	isLoading: boolean;
@@ -281,6 +290,7 @@ const ToolBadge: FC<{
 
 export const AgentChatInput: FC<AgentChatInputProps> = ({
 	onSend,
+	sendShortcut = DEFAULT_AGENT_CHAT_SEND_SHORTCUT,
 	placeholder = "Type a message...",
 	isDisabled,
 	isLoading,
@@ -845,6 +855,14 @@ export const AgentChatInput: FC<AgentChatInputProps> = ({
 			: isEditingHistoryMessage
 				? "Save Edit"
 				: "Send";
+	const sendShortcutLabel =
+		sendShortcut === MODIFIER_AGENT_CHAT_SEND_SHORTCUT
+			? "Cmd/Ctrl+Enter"
+			: "Enter";
+	const sendButtonKeyShortcuts =
+		sendShortcut === MODIFIER_AGENT_CHAT_SEND_SHORTCUT
+			? "Control+Enter Meta+Enter"
+			: "Enter";
 
 	const content = (
 		<div
@@ -949,6 +967,7 @@ export const AgentChatInput: FC<AgentChatInputProps> = ({
 					onChange={handleContentChange}
 					onKeyDown={handleEditorKeyDown}
 					onEnter={handleSubmit}
+					sendShortcut={sendShortcut}
 					disabled={isDisabled || isLoading}
 					autoFocus
 				/>
@@ -1334,26 +1353,38 @@ export const AgentChatInput: FC<AgentChatInputProps> = ({
 							</Button>
 						)}
 						{!(isStreaming && editingQueuedMessageID === null) && (
-							<Button
-								size="icon"
-								variant="default"
-								className="size-7 rounded-full transition-colors [&>svg]:!size-5 [&>svg]:p-0"
-								onClick={
-									speech.isRecording ? handleAcceptRecording : handleSubmit
-								}
-								disabled={speech.isRecording ? false : !canSend}
-							>
-								{isLoading ? (
-									<Spinner size="sm" loading aria-hidden="true" />
-								) : speech.isRecording ? (
-									<CheckIcon />
-								) : (
-									<ArrowUpIcon />
-								)}
-								<span className="sr-only">
-									{speech.isRecording ? "Accept voice input" : sendButtonLabel}
-								</span>
-							</Button>
+							<Tooltip>
+								<TooltipTrigger asChild>
+									<Button
+										size="icon"
+										variant="default"
+										className="size-7 rounded-full transition-colors [&>svg]:!size-5 [&>svg]:p-0"
+										onClick={
+											speech.isRecording ? handleAcceptRecording : handleSubmit
+										}
+										disabled={speech.isRecording ? false : !canSend}
+										aria-keyshortcuts={sendButtonKeyShortcuts}
+									>
+										{isLoading ? (
+											<Spinner size="sm" loading aria-hidden="true" />
+										) : speech.isRecording ? (
+											<CheckIcon />
+										) : (
+											<ArrowUpIcon />
+										)}
+										<span className="sr-only">
+											{speech.isRecording
+												? "Accept voice input"
+												: sendButtonLabel}
+										</span>
+									</Button>
+								</TooltipTrigger>
+								<TooltipContent side="top">
+									{speech.isRecording
+										? "Accept voice input"
+										: `${sendButtonLabel}: ${sendShortcutLabel}`}
+								</TooltipContent>
+							</Tooltip>
 						)}
 					</div>
 				</div>

site/src/pages/AgentsPage/components/AgentCreateForm.stories.tsx

@@ -108,6 +108,7 @@ const meta: Meta<typeof AgentCreateForm> = {
 	decorators: [withDashboardProvider],
 	args: {
 		onCreateChat: fn(),
+		sendShortcut: "enter",
 		isCreating: false,
 		createError: undefined,
 		canCreateChat: true,

site/src/pages/AgentsPage/components/AgentCreateForm.tsx

@@ -12,6 +12,7 @@ import { toast } from "sonner";
 import { isApiError } from "#/api/errors";
 import { permittedOrganizations } from "#/api/queries/organizations";
 import type * as TypesGen from "#/api/typesGenerated";
+import type { AgentChatSendShortcut } from "#/api/typesGenerated";
 import { Alert, AlertDescription } from "#/components/Alert/Alert";
 import { ErrorAlert } from "#/components/Alert/ErrorAlert";
 import { Button } from "#/components/Button/Button";
@@ -125,6 +126,7 @@ export function useEmptyStateDraft() {
 
 interface AgentCreateFormProps {
 	onCreateChat: (options: CreateChatOptions) => Promise<void>;
+	sendShortcut: AgentChatSendShortcut;
 	isCreating: boolean;
 	createError: unknown;
 	canCreateChat: boolean;
@@ -146,6 +148,7 @@ interface AgentCreateFormProps {
 
 export const AgentCreateForm: FC<AgentCreateFormProps> = ({
 	onCreateChat,
+	sendShortcut,
 	isCreating,
 	createError,
 	canCreateChat,
@@ -509,6 +512,7 @@ export const AgentCreateForm: FC<AgentCreateFormProps> = ({
 					{agentSetupNotice}
 					<AgentChatInput
 						onSend={handleSendWithAttachments}
+						sendShortcut={sendShortcut}
 						placeholder="Ask Coder to build, fix bugs, or explore your project..."
 						isDisabled={
 							isCreating || isForbidden || isPersonalModelOverridesLoading

site/src/pages/AgentsPage/components/ChatConversation/ConversationTimeline.stories.tsx

@@ -1763,6 +1763,7 @@ export const CodeDiffDisplayModeFromPreferences: Story = {
 					task_notification_alert_dismissed: false,
 					thinking_display_mode: "auto" as const,
 					code_diff_display_mode: "always_collapsed" as const,
+					agent_chat_send_shortcut: "enter" as const,
 				},
 			},
 		],
@@ -1839,6 +1840,7 @@ export const ThinkingBlockAlwaysExpanded: Story = {
 					task_notification_alert_dismissed: false,
 					thinking_display_mode: "always_expanded" as const,
 					code_diff_display_mode: "auto" as const,
+					agent_chat_send_shortcut: "enter" as const,
 				},
 			},
 		],
@@ -1887,6 +1889,7 @@ export const ThinkingBlockAlwaysCollapsed: Story = {
 					task_notification_alert_dismissed: false,
 					thinking_display_mode: "always_collapsed" as const,
 					code_diff_display_mode: "auto" as const,
+					agent_chat_send_shortcut: "enter" as const,
 				},
 			},
 		],
@@ -1936,6 +1939,7 @@ export const ThinkingBlockWithToolCall: Story = {
 					task_notification_alert_dismissed: false,
 					thinking_display_mode: "always_collapsed" as const,
 					code_diff_display_mode: "auto" as const,
+					agent_chat_send_shortcut: "enter" as const,
 				},
 			},
 		],
@@ -1998,6 +2002,7 @@ export const ThinkingBlockAutoMode: Story = {
 					task_notification_alert_dismissed: false,
 					thinking_display_mode: "auto" as const,
 					code_diff_display_mode: "auto" as const,
+					agent_chat_send_shortcut: "enter" as const,
 				},
 			},
 		],
@@ -2050,6 +2055,7 @@ export const ThinkingBlockPreviewMode: Story = {
 					task_notification_alert_dismissed: false,
 					thinking_display_mode: "preview" as const,
 					code_diff_display_mode: "auto" as const,
+					agent_chat_send_shortcut: "enter" as const,
 				},
 			},
 		],

site/src/pages/AgentsPage/components/ChatMessageInput/ChatMessageInput.tsx

@@ -29,8 +29,13 @@ import {
 	useLayoutEffect,
 	useRef,
 } from "react";
+import type { AgentChatSendShortcut } from "#/api/typesGenerated";
 import { cn } from "#/utils/cn";
 import { isMobileViewport } from "#/utils/mobile";
+import {
+	DEFAULT_AGENT_CHAT_SEND_SHORTCUT,
+	MODIFIER_AGENT_CHAT_SEND_SHORTCUT,
+} from "../../utils/agentChatSendShortcut";
 import { isChatAttachmentFile } from "../../utils/chatAttachments";
 import {
 	$createFileReferenceNode,
@@ -257,21 +262,40 @@ const PasteSanitizationPlugin: FC<{
 	return null;
 };
 
-// Handles Enter key behavior: plain Enter submits via the onEnter
-// callback, Shift+Enter inserts a newline. On mobile viewports, Enter
-// always inserts a newline; users submit via the send button because
+// Handles Enter key behavior. By default, plain Enter submits via
+// the onEnter callback, and Shift+Enter inserts a newline. When the
+// modifier shortcut is selected, Cmd/Ctrl+Enter submits instead, and
+// plain Enter inserts a newline. On mobile viewports, Enter always
+// inserts a newline; users submit via the send button because
 // Shift+Enter is cumbersome on touch keyboards (CODAGT-210).
-const EnterKeyPlugin: FC<{ onEnter?: () => void }> = function EnterKeyPlugin({
-	onEnter,
-}) {
+const EnterKeyPlugin: FC<{
+	onEnter?: () => void;
+	sendShortcut: AgentChatSendShortcut;
+}> = function EnterKeyPlugin({ onEnter, sendShortcut }) {
 	const [editor] = useLexicalComposerContext();
 
 	useEffect(() => {
 		return editor.registerCommand(
 			KEY_ENTER_COMMAND,
 			(event: KeyboardEvent | null) => {
-				if (event?.shiftKey || isMobileViewport()) {
-					return false;
+				const shouldInsertLineBreak =
+					event?.shiftKey ||
+					isMobileViewport() ||
+					(sendShortcut === MODIFIER_AGENT_CHAT_SEND_SHORTCUT &&
+						!(event?.metaKey || event?.ctrlKey));
+				if (shouldInsertLineBreak) {
+					event?.preventDefault();
+					editor.update(() => {
+						let selection = $getSelection();
+						if (!$isRangeSelection(selection)) {
+							$getRoot().selectEnd();
+							selection = $getSelection();
+						}
+						if ($isRangeSelection(selection)) {
+							selection.insertLineBreak();
+						}
+					});
+					return true;
 				}
 				if (onEnter) {
 					event?.preventDefault();
@@ -281,7 +305,7 @@ const EnterKeyPlugin: FC<{ onEnter?: () => void }> = function EnterKeyPlugin({
 			},
 			COMMAND_PRIORITY_HIGH,
 		);
-	}, [editor, onEnter]);
+	}, [editor, onEnter, sendShortcut]);
 
 	return null;
 };
@@ -456,6 +480,7 @@ interface ChatMessageInputProps
 	remountKey?: number;
 	rows?: number;
 	onEnter?: () => void;
+	sendShortcut?: AgentChatSendShortcut;
 	onFilePaste?: (file: File) => void;
 	allowTextAttachmentPaste?: boolean;
 	disabled?: boolean;
@@ -486,6 +511,7 @@ const ChatMessageInput = ({
 	remountKey,
 	rows,
 	onEnter,
+	sendShortcut = DEFAULT_AGENT_CHAT_SEND_SHORTCUT,
 	onFilePaste,
 	allowTextAttachmentPaste,
 	disabled,
@@ -706,7 +732,10 @@ const ChatMessageInput = ({
 					onFilePaste={onFilePaste}
 					allowTextAttachmentPaste={allowTextAttachmentPaste}
 				/>
-				<EnterKeyPlugin onEnter={disabled ? undefined : onEnter} />
+				<EnterKeyPlugin
+					onEnter={disabled ? undefined : onEnter}
+					sendShortcut={sendShortcut}
+				/>
 				<ContentChangePlugin onChange={onChange} />
 				<ValueSyncPlugin
 					initialValue={initialValue}

site/src/pages/AgentsPage/components/ChatPageContent.tsx

@@ -2,6 +2,7 @@ import { type FC, Profiler, type ReactNode, useEffect, useRef } from "react";
 import { toast } from "sonner";
 import type { UrlTransform } from "streamdown";
 import type * as TypesGen from "#/api/typesGenerated";
+import type { AgentChatSendShortcut } from "#/api/typesGenerated";
 import { cn } from "#/utils/cn";
 import { useChatDraftAttachments } from "../hooks/useChatDraftAttachments";
 import { chatWidthClass, useChatFullWidth } from "../hooks/useChatFullWidth";
@@ -150,6 +151,7 @@ interface ChatPageInputProps {
 		message: string,
 		attachments?: readonly PendingAttachment[],
 	) => Promise<void> | void;
+	sendShortcut: AgentChatSendShortcut;
 	onDeleteQueuedMessage: (id: number) => Promise<void>;
 	onPromoteQueuedMessage: (id: number) => Promise<void>;
 	onInterrupt: () => void;
@@ -214,6 +216,7 @@ export const ChatPageInput: FC<ChatPageInputProps> = ({
 	store,
 	compressionThreshold,
 	onSend,
+	sendShortcut,
 	onDeleteQueuedMessage,
 	onPromoteQueuedMessage,
 	onInterrupt,
@@ -445,6 +448,7 @@ export const ChatPageInput: FC<ChatPageInputProps> = ({
 					}
 				})();
 			}}
+			sendShortcut={sendShortcut}
 			attachments={attachments}
 			onAttach={handleAttach}
 			onRemoveAttachment={handleRemoveAttachment}

site/src/pages/AgentsPage/components/ChatSendShortcutSettings.tsx

@@ -0,0 +1,56 @@
+import { type FC, useId } from "react";
+import { useMutation, useQuery, useQueryClient } from "react-query";
+import {
+	preferenceSettings,
+	updatePreferenceSettings,
+} from "#/api/queries/users";
+import { Switch } from "#/components/Switch/Switch";
+import {
+	DEFAULT_AGENT_CHAT_SEND_SHORTCUT,
+	MODIFIER_AGENT_CHAT_SEND_SHORTCUT,
+} from "../utils/agentChatSendShortcut";
+
+export const ChatSendShortcutSettings: FC = () => {
+	const queryClient = useQueryClient();
+	const query = useQuery(preferenceSettings());
+	const mutation = useMutation(updatePreferenceSettings(queryClient));
+	const descriptionId = useId();
+	const shortcut =
+		query.data?.agent_chat_send_shortcut ?? DEFAULT_AGENT_CHAT_SEND_SHORTCUT;
+	const requiresModifierEnter = shortcut === MODIFIER_AGENT_CHAT_SEND_SHORTCUT;
+
+	return (
+		<div className="flex flex-col gap-2">
+			<h3 className="m-0 text-sm font-semibold text-content-primary">
+				Keyboard Shortcuts
+			</h3>
+			<div className="flex items-center justify-between gap-4">
+				<p
+					id={descriptionId}
+					className="m-0 flex-1 text-xs text-content-secondary"
+				>
+					Require Cmd/Ctrl+Enter to send agent messages. When enabled, Enter
+					inserts a newline instead.
+				</p>
+				<Switch
+					checked={requiresModifierEnter}
+					onCheckedChange={(checked) =>
+						mutation.mutate({
+							agent_chat_send_shortcut: checked
+								? MODIFIER_AGENT_CHAT_SEND_SHORTCUT
+								: DEFAULT_AGENT_CHAT_SEND_SHORTCUT,
+						})
+					}
+					aria-label="Require Cmd/Ctrl+Enter to send messages"
+					aria-describedby={descriptionId}
+					disabled={query.isLoading || !query.data || mutation.isPending}
+				/>
+			</div>
+			{mutation.isError && (
+				<p className="m-0 text-xs text-content-destructive">
+					Failed to save your keyboard shortcut preference.
+				</p>
+			)}
+		</div>
+	);
+};

site/src/pages/AgentsPage/utils/agentChatSendShortcut.test.ts

@@ -0,0 +1,26 @@
+import { describe, expect, it } from "vitest";
+import {
+	DEFAULT_AGENT_CHAT_SEND_SHORTCUT,
+	getAgentChatSendShortcut,
+	MODIFIER_AGENT_CHAT_SEND_SHORTCUT,
+} from "./agentChatSendShortcut";
+
+describe("getAgentChatSendShortcut", () => {
+	it("returns the stored shortcut when present", () => {
+		expect(
+			getAgentChatSendShortcut(MODIFIER_AGENT_CHAT_SEND_SHORTCUT, false),
+		).toBe(MODIFIER_AGENT_CHAT_SEND_SHORTCUT);
+	});
+
+	it("uses the modifier shortcut while preferences are loading", () => {
+		expect(getAgentChatSendShortcut(undefined, true)).toBe(
+			MODIFIER_AGENT_CHAT_SEND_SHORTCUT,
+		);
+	});
+
+	it("uses the default shortcut after preferences finish loading", () => {
+		expect(getAgentChatSendShortcut(undefined, false)).toBe(
+			DEFAULT_AGENT_CHAT_SEND_SHORTCUT,
+		);
+	});
+});

site/src/pages/AgentsPage/utils/agentChatSendShortcut.ts

@@ -0,0 +1,20 @@
+import type { AgentChatSendShortcut } from "#/api/typesGenerated";
+
+export const DEFAULT_AGENT_CHAT_SEND_SHORTCUT: AgentChatSendShortcut = "enter";
+export const MODIFIER_AGENT_CHAT_SEND_SHORTCUT: AgentChatSendShortcut =
+	"modifier_enter";
+
+export function getAgentChatSendShortcut(
+	storedShortcut: AgentChatSendShortcut | undefined,
+	isLoading: boolean,
+): AgentChatSendShortcut {
+	if (storedShortcut) {
+		return storedShortcut;
+	}
+	// Keep the loading fallback conservative. If a user saved
+	// modifier_enter, falling back to enter before preferences load can
+	// send a draft when they intended to insert a newline.
+	return isLoading
+		? MODIFIER_AGENT_CHAT_SEND_SHORTCUT
+		: DEFAULT_AGENT_CHAT_SEND_SHORTCUT;
+}

site/src/pages/UserSettingsPage/NotificationsPage/NotificationsPage.stories.tsx

@@ -216,6 +216,7 @@ export const EnablingTaskNotificationClearsAlertDismissal: Story = {
 					task_notification_alert_dismissed: true,
 					thinking_display_mode: "auto" as const,
 					code_diff_display_mode: "auto" as const,
+					agent_chat_send_shortcut: "enter" as const,
 				},
 			},
 		],
@@ -240,6 +241,7 @@ export const EnablingTaskNotificationClearsAlertDismissal: Story = {
 			task_notification_alert_dismissed: false,
 			thinking_display_mode: "auto",
 			code_diff_display_mode: "auto",
+			agent_chat_send_shortcut: "enter" as const,
 		});
 
 		await step("Enable Task Idle notification", async () => {