Add todos update command

.surface

@@ -265,6 +265,7 @@ CMD basecamp todos show
 CMD basecamp todos sweep
 CMD basecamp todos trash
 CMD basecamp todos uncomplete
+CMD basecamp todos update
 CMD basecamp todosets
 CMD basecamp todosets list
 CMD basecamp todosets show
@@ -6156,6 +6157,33 @@ FLAG basecamp todos uncomplete --stats type=bool
 FLAG basecamp todos uncomplete --styled type=bool
 FLAG basecamp todos uncomplete --todolist type=string
 FLAG basecamp todos uncomplete --verbose type=count
+FLAG basecamp todos update --account type=string
+FLAG basecamp todos update --agent type=bool
+FLAG basecamp todos update --assignee type=string
+FLAG basecamp todos update --cache-dir type=string
+FLAG basecamp todos update --count type=bool
+FLAG basecamp todos update --description type=string
+FLAG basecamp todos update --due type=string
+FLAG basecamp todos update --hints type=bool
+FLAG basecamp todos update --ids-only type=bool
+FLAG basecamp todos update --in type=string
+FLAG basecamp todos update --jq type=string
+FLAG basecamp todos update --json type=bool
+FLAG basecamp todos update --markdown type=bool
+FLAG basecamp todos update --md type=bool
+FLAG basecamp todos update --no-hints type=bool
+FLAG basecamp todos update --no-stats type=bool
+FLAG basecamp todos update --notify type=bool
+FLAG basecamp todos update --profile type=string
+FLAG basecamp todos update --project type=string
+FLAG basecamp todos update --quiet type=bool
+FLAG basecamp todos update --starts-on type=string
+FLAG basecamp todos update --stats type=bool
+FLAG basecamp todos update --styled type=bool
+FLAG basecamp todos update --title type=string
+FLAG basecamp todos update --to type=string
+FLAG basecamp todos update --todolist type=string
+FLAG basecamp todos update --verbose type=count
 FLAG basecamp todosets --account type=string
 FLAG basecamp todosets --agent type=bool
 FLAG basecamp todosets --cache-dir type=string
@@ -7414,6 +7442,7 @@ SUB basecamp todos show
 SUB basecamp todos sweep
 SUB basecamp todos trash
 SUB basecamp todos uncomplete
+SUB basecamp todos update
 SUB basecamp todosets
 SUB basecamp todosets list
 SUB basecamp todosets show

API-COVERAGE.md

@@ -22,7 +22,7 @@ Out-of-scope sections are excluded from parity totals and scripts: chatbots (dif
 |---------|-----------|-------------|--------|----------|-------|
 | **Core** |
 | projects | 9 | `projects` | ✅ | - | list, show, create, update, delete |
-| todos | 11 | `todos`, `todo`, `done`, `reopen` | ✅ | - | list, show, create, complete, uncomplete, position |
+| todos | 11 | `todos`, `todo`, `done`, `reopen` | ✅ | - | list, show, create, update, complete, uncomplete, position |
 | todolists | 8 | `todolists` | ✅ | - | list, show, create, update |
 | todosets | 3 | `todosets` | ✅ | - | Container for todolists, accessed via project dock |
 | todolist_groups | 8 | `todolistgroups` | ✅ | - | list, show, create, update, position |

e2e/smoke/smoke_todos_write.bats

@@ -85,6 +85,17 @@ setup_file() {
   assert_json_value '.ok' 'true'
 }
 
+@test "todos update updates a todo" {
+  local id_file="$BATS_FILE_TMPDIR/direct_todo_id"
+  [[ -f "$id_file" ]] || mark_unverifiable "No direct todo created in prior test"
+  local todo_id
+  todo_id=$(<"$id_file")
+
+  run_smoke basecamp todos update "$todo_id" --title "Updated smoke todo $(date +%s)" -p "$QA_PROJECT" --json
+  assert_success
+  assert_json_value '.ok' 'true'
+}
+
 @test "todos trash trashes a todo" {
   local id_file="$BATS_FILE_TMPDIR/direct_todo_id"
   [[ -f "$id_file" ]] || mark_unverifiable "No direct todo created in prior test"

go.mod

@@ -6,7 +6,7 @@ require (
 	charm.land/bubbles/v2 v2.0.0
 	charm.land/bubbletea/v2 v2.0.2
 	charm.land/lipgloss/v2 v2.0.2
-	github.com/basecamp/basecamp-sdk/go v0.6.1-0.20260318172136-4784bb2fda18
+	github.com/basecamp/basecamp-sdk/go v0.6.1-0.20260318221909-49475983b9c8
 	github.com/basecamp/cli v0.1.1
 	github.com/charmbracelet/bubbles v1.0.0
 	github.com/charmbracelet/glamour v1.0.0

go.sum

@@ -25,8 +25,8 @@ github.com/aymanbagabas/go-udiff v0.4.1 h1:OEIrQ8maEeDBXQDoGCbbTTXYJMYRCRO1fnodZ
 github.com/aymanbagabas/go-udiff v0.4.1/go.mod h1:0L9PGwj20lrtmEMeyw4WKJ/TMyDtvAoK9bf2u/mNo3w=
 github.com/aymerick/douceur v0.2.0 h1:Mv+mAeH1Q+n9Fr+oyamOlAkUNPWPlA8PPGR0QAaYuPk=
 github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd30/FjWUq4=
-github.com/basecamp/basecamp-sdk/go v0.6.1-0.20260318172136-4784bb2fda18 h1:it4iTTmOKr4DFOdVGE7jVxNQ3lD9snwe8vYhVI8Soz4=
-github.com/basecamp/basecamp-sdk/go v0.6.1-0.20260318172136-4784bb2fda18/go.mod h1:g05DM58QkUm4/mvBAvRiugPw+F4trliuGkRGg8y+Th4=
+github.com/basecamp/basecamp-sdk/go v0.6.1-0.20260318221909-49475983b9c8 h1:WsLan1O+1GWBSQEn+dTd63roBunjojffjaoKnQ4g33U=
+github.com/basecamp/basecamp-sdk/go v0.6.1-0.20260318221909-49475983b9c8/go.mod h1:g05DM58QkUm4/mvBAvRiugPw+F4trliuGkRGg8y+Th4=
 github.com/basecamp/cli v0.1.1 h1:FAF3M09xo1m7gJJXf38glCkT50ZUuvz+31f+c3R3zcc=
 github.com/basecamp/cli v0.1.1/go.mod h1:NTHe+keCTGI2qM5sMXdkUN0QgU3zGbwnBxcmg8vD5QU=
 github.com/bmatcuk/doublestar v1.1.1/go.mod h1:UD6OnuiIn0yFxxA2le/rnRU1G4RaI4UvFv1sNto9p6w=

internal/commands/checkins.go

@@ -344,8 +344,8 @@ Days format: comma-separated (0=Sun, 1=Mon, 2=Tue, 3=Wed, 4=Thu, 5=Fri, 6=Sat)`,
 				Schedule: &basecamp.QuestionSchedule{
 					Frequency: frequency,
 					Days:      daysArray,
-					Hour:      hour,
-					Minute:    minute,
+					Hour:      &hour,
+					Minute:    &minute,
 				},
 			}
 
@@ -457,8 +457,8 @@ You can pass either a question ID or a Basecamp URL:
 					if err != nil {
 						return output.ErrUsage("Invalid time format: " + timeOfDay)
 					}
-					schedule.Hour = hour
-					schedule.Minute = minute
+					schedule.Hour = &hour
+					schedule.Minute = &minute
 				}
 				if days != "" {
 					dayParts := strings.Split(days, ",")

internal/commands/commands.go

@@ -35,7 +35,7 @@ func CommandCategories() []CommandCategory {
 			Name: "Core Commands",
 			Commands: []CommandInfo{
 				{Name: "projects", Category: "core", Description: "Manage projects", Actions: []string{"list", "show", "create", "update", "delete"}},
-				{Name: "todos", Category: "core", Description: "Manage to-dos", Actions: []string{"list", "show", "create", "complete", "uncomplete", "position", "trash", "archive", "restore"}},
+				{Name: "todos", Category: "core", Description: "Manage to-dos", Actions: []string{"list", "show", "create", "update", "complete", "uncomplete", "position", "trash", "archive", "restore"}},
 				{Name: "todolists", Category: "core", Description: "Manage to-do lists", Actions: []string{"list", "show", "create", "update", "trash", "archive", "restore"}},
 				{Name: "todosets", Category: "core", Description: "Manage to-do set containers", Actions: []string{"list", "show"}},
 				{Name: "todolistgroups", Category: "core", Description: "Manage to-do list groups", Actions: []string{"list", "show", "create", "update", "position"}},

internal/commands/schedule.go

@@ -488,7 +488,7 @@ func runScheduleCreate(cmd *cobra.Command, app *appctx.App, project, scheduleID,
 		StartsAt:      startsAt,
 		EndsAt:        endsAt,
 		Description:   description,
-		AllDay:        allDay,
+		AllDay:        &allDay,
 		Notify:        notify,
 		Subscriptions: subs,
 	}
@@ -618,7 +618,7 @@ You can pass either an entry ID or a Basecamp URL:
 				hasChanges = true
 			}
 			if cmd.Flags().Changed("all-day") {
-				req.AllDay = allDay
+				req.AllDay = &allDay
 				hasChanges = true
 			}
 			if cmd.Flags().Changed("notify") {

internal/commands/todos.go

@@ -49,6 +49,7 @@ func NewTodosCmd() *cobra.Command {
 		newTodosListCmd(),
 		newTodosShowCmd(),
 		newTodosCreateCmd(),
+		newTodosUpdateCmd(),
 		newTodosCompleteCmd(),
 		newTodosUncompleteCmd(),
 		newTodosSweepCmd(),
@@ -723,6 +724,11 @@ You can pass either a todo ID or a Basecamp URL:
 			return app.OK(todo,
 				output.WithEntity("todo"),
 				output.WithBreadcrumbs(
+					output.Breadcrumb{
+						Action:      "update",
+						Cmd:         fmt.Sprintf("basecamp todos update %d --title <title>", todoID),
+						Description: "Update this todo",
+					},
 					output.Breadcrumb{
 						Action:      "complete",
 						Cmd:         fmt.Sprintf("basecamp done %d", todoID),
@@ -919,6 +925,137 @@ func newTodosCreateCmd() *cobra.Command {
 	return cmd
 }
 
+func newTodosUpdateCmd() *cobra.Command {
+	var title string
+	var description string
+	var assignee string
+	var due string
+	var startsOn string
+	var notify bool
+
+	cmd := &cobra.Command{
+		Use:   "update <id|url> [title]",
+		Short: "Update a todo",
+		Long: `Update an existing todo.
+
+You can pass either a todo ID or a Basecamp URL:
+  basecamp todos update 789 "New title"
+  basecamp todos update 789 --title "New title"
+  basecamp todos update 789 --due "next friday"
+  basecamp todos update https://3.basecamp.com/123/buckets/456/todos/789 --description "Details"`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) == 0 {
+				return missingArg(cmd, "<id|url>")
+			}
+
+			// Positional title: args[1:] joined
+			positionalTitle := strings.Join(args[1:], " ")
+
+			// Effective title: positional takes precedence over --title flag
+			effectiveTitle := title
+			if strings.TrimSpace(positionalTitle) != "" {
+				effectiveTitle = positionalTitle
+			}
+
+			// No-op guard: at least one effective field required
+			assigneeChanged := (cmd.Flags().Changed("assignee") || cmd.Flags().Changed("to")) && strings.TrimSpace(assignee) != ""
+			if strings.TrimSpace(effectiveTitle) == "" &&
+				strings.TrimSpace(description) == "" &&
+				strings.TrimSpace(due) == "" && strings.TrimSpace(startsOn) == "" &&
+				!assigneeChanged &&
+				(!cmd.Flags().Changed("notify") || !notify) {
+				return noChanges(cmd)
+			}
+
+			app := appctx.FromContext(cmd.Context())
+			if app == nil {
+				return fmt.Errorf("app not initialized")
+			}
+
+			if err := ensureAccount(cmd, app); err != nil {
+				return err
+			}
+
+			// Extract ID from URL if provided
+			todoIDStr := extractID(args[0])
+			todoID, err := strconv.ParseInt(todoIDStr, 10, 64)
+			if err != nil {
+				return output.ErrUsage("Invalid todo ID")
+			}
+
+			req := &basecamp.UpdateTodoRequest{}
+			if effectiveTitle != "" {
+				req.Content = effectiveTitle
+			}
+			if description != "" {
+				descHTML := richtext.MarkdownToHTML(description)
+				descHTML, err = resolveLocalImages(cmd, app, descHTML)
+				if err != nil {
+					return err
+				}
+				req.Description = descHTML
+			}
+			if strings.TrimSpace(due) != "" {
+				if parsed := dateparse.Parse(due); parsed != "" {
+					req.DueOn = parsed
+				}
+			}
+			if strings.TrimSpace(startsOn) != "" {
+				if parsed := dateparse.Parse(startsOn); parsed != "" {
+					req.StartsOn = parsed
+				}
+			}
+			if assigneeChanged {
+				assigneeIDs, err := resolveAssigneeIDs(cmd.Context(), app, assignee)
+				if err != nil {
+					return err
+				}
+				req.AssigneeIDs = assigneeIDs
+			}
+			if cmd.Flags().Changed("notify") && notify {
+				req.Notify = true
+			}
+
+			todo, err := app.Account().Todos().Update(cmd.Context(), todoID, req)
+			if err != nil {
+				return convertSDKError(err)
+			}
+
+			return app.OK(todo,
+				output.WithEntity("todo"),
+				output.WithSummary(fmt.Sprintf("Updated todo #%s", todoIDStr)),
+				output.WithBreadcrumbs(
+					output.Breadcrumb{
+						Action:      "show",
+						Cmd:         fmt.Sprintf("basecamp todos show %s", todoIDStr),
+						Description: "View todo",
+					},
+					output.Breadcrumb{
+						Action:      "complete",
+						Cmd:         fmt.Sprintf("basecamp done %s", todoIDStr),
+						Description: "Complete todo",
+					},
+				),
+			)
+		},
+	}
+
+	cmd.Flags().StringVarP(&title, "title", "t", "", "Todo title (plain text)")
+	cmd.Flags().StringVar(&description, "description", "", "Extended description (Markdown)")
+	cmd.Flags().StringVar(&assignee, "assignee", "", "Assignees (names or IDs, comma-separated)")
+	cmd.Flags().StringVar(&assignee, "to", "", "Assignees (alias for --assignee)")
+	cmd.Flags().StringVarP(&due, "due", "d", "", "Due date (natural language or YYYY-MM-DD)")
+	cmd.Flags().StringVar(&startsOn, "starts-on", "", "Start date (natural language or YYYY-MM-DD)")
+	cmd.Flags().BoolVar(&notify, "notify", false, "Notify assignees")
+
+	// Register tab completion for assignee flags
+	completer := completion.NewCompleter(nil)
+	_ = cmd.RegisterFlagCompletionFunc("assignee", completer.PeopleNameCompletion())
+	_ = cmd.RegisterFlagCompletionFunc("to", completer.PeopleNameCompletion())
+
+	return cmd
+}
+
 func newTodosCompleteCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "complete <id|url>...",