Add --by flag to filter answers by person

.surface

@@ -3479,6 +3479,7 @@ FLAG basecamp checkin answer update --verbose type=count
 FLAG basecamp checkin answers --account type=string
 FLAG basecamp checkin answers --agent type=bool
 FLAG basecamp checkin answers --all type=bool
+FLAG basecamp checkin answers --by type=string
 FLAG basecamp checkin answers --cache-dir type=string
 FLAG basecamp checkin answers --count type=bool
 FLAG basecamp checkin answers --help type=bool
@@ -3747,6 +3748,7 @@ FLAG basecamp checkins answer update --verbose type=count
 FLAG basecamp checkins answers --account type=string
 FLAG basecamp checkins answers --agent type=bool
 FLAG basecamp checkins answers --all type=bool
+FLAG basecamp checkins answers --by type=string
 FLAG basecamp checkins answers --cache-dir type=string
 FLAG basecamp checkins answers --count type=bool
 FLAG basecamp checkins answers --help type=bool

internal/commands/checkins.go

@@ -528,6 +528,7 @@
 	var limit int
 	var page int
 	var all bool
+	var by string
 
 	cmd := &cobra.Command{
 		Use:   "answers <question_id|url>",
@@ -536,7 +537,11 @@
 
 You can pass either a question ID or a Basecamp URL:
   basecamp checkins answers 789 --in my-project
-  basecamp checkins answers https://3.basecamp.com/123/buckets/456/questions/789`,
+  basecamp checkins answers https://3.basecamp.com/123/buckets/456/questions/789
+
+Use --by to filter answers by a specific person (name, email, ID, or "me"):
+  basecamp checkins answers 789 --by me --in my-project
+  basecamp checkins answers 789 --by "Alice Smith" --in my-project`,
 		Args: cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			app := appctx.FromContext(cmd.Context())
@@ -598,11 +603,33 @@
 				opts.Page = page
 			}
 
-			answersResult, err := app.Account().Checkins().ListAnswers(cmd.Context(), questionID, opts)
-			if err != nil {
-				return convertSDKError(err)
+			trimmedBy := strings.TrimSpace(by)
+			if by != "" && trimmedBy == "" {
+				return output.ErrUsage("--by value cannot be blank")
+			}
+
+			var answers []basecamp.QuestionAnswer
+			if trimmedBy != "" {
+				personIDStr, _, err := app.Names.ResolvePerson(cmd.Context(), trimmedBy)
+				if err != nil {
+					return err
+				}
+				personID, err := strconv.ParseInt(personIDStr, 10, 64)
+				if err != nil {
+					return output.ErrUsage("Invalid person ID")
+				}
+				answersResult, err := app.Account().Checkins().ListAnswersByUser(cmd.Context(), questionID, personID, opts)
+				if err != nil {
+					return convertSDKError(err)
+				}
+				answers = answersResult.Answers
+			} else {
+				answersResult, err := app.Account().Checkins().ListAnswers(cmd.Context(), questionID, opts)
+				if err != nil {
+					return convertSDKError(err)
+				}
+				answers = answersResult.Answers
 			}
-			answers := answersResult.Answers
 
 			return app.OK(answers,
 				output.WithSummary(fmt.Sprintf("%d answers", len(answers))),
@@ -625,6 +652,7 @@
 	cmd.Flags().IntVarP(&limit, "limit", "n", 0, "Maximum number of answers to fetch (0 = all)")
 	cmd.Flags().BoolVar(&all, "all", false, "Fetch all answers (no limit)")
 	cmd.Flags().IntVar(&page, "page", 0, "Fetch a single page (use --all for everything)")
+	cmd.Flags().StringVar(&by, "by", "", "Filter answers by person (name, email, ID, or \"me\")")
 
 	return cmd
 }

internal/commands/checkins_test.go

@@ -12,6 +12,66 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+type mockCheckinsAnswersByPersonTransport struct {
+	recordedPath string
+}
+
+func (m *mockCheckinsAnswersByPersonTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	header := make(http.Header)
+	header.Set("Content-Type", "application/json")
+
+	switch {
+	case req.Method == "GET" && strings.Contains(req.URL.Path, "/projects.json"):
+		return &http.Response{
+			StatusCode: 200,
+			Body:       io.NopCloser(strings.NewReader(`[{"id":123,"name":"Test Project"}]`)),
+			Header:     header,
+		}, nil
+	case req.Method == "GET" && strings.Contains(req.URL.Path, "/people.json"):
+		return &http.Response{
+			StatusCode: 200,
+			Body:       io.NopCloser(strings.NewReader(`[{"id":456,"name":"Alice Smith","email_address":"alice@example.com"}]`)),
+			Header:     header,
+		}, nil
+	case req.Method == "GET" && strings.Contains(req.URL.Path, "/questions/789/answers/by/456"):
+		m.recordedPath = req.URL.Path
+		return &http.Response{
+			StatusCode: 200,
+			Body: io.NopCloser(strings.NewReader(`[{
+				"id": 1001,
+				"content": "<div>Alice's answer</div>",
+				"group_on": "2026-04-21",
+				"creator": {"id": 456, "name": "Alice Smith"},
+				"parent": {"id": 789, "title": "What did you work on?", "type": "Question", "url": "https://example.test/questions/789", "app_url": "https://example.test/questions/789"},
+				"bucket": {"id": 123, "name": "Test Project", "type": "Project"},
+				"status": "active",
+				"type": "Question::Answer",
+				"title": "What did you work on?"
+			}]`)),
+			Header: header,
+		}, nil
+	default:
+		return &http.Response{
+			StatusCode: 404,
+			Body:       io.NopCloser(strings.NewReader(`{"error":"Not Found"}`)),
+			Header:     header,
+		}, nil
+	}
+}
+
+func TestCheckinsAnswersByPersonFlag(t *testing.T) {
+	transport := &mockCheckinsAnswersByPersonTransport{}
+	app, _ := newTestAppWithTransport(t, transport)
+	app.Config.ProjectID = "123"
+
+	project := ""
+	cmd := newCheckinsAnswersCmd(&project)
+
+	err := executeCommand(cmd, app, "789", "--by", "Alice Smith")
+	require.NoError(t, err)
+	assert.Contains(t, transport.recordedPath, "/questions/789/answers/by/456")
+}
+
 type mockCheckinsAnswerCreateTransport struct {
 	recordedPath string
 	recordedBody map[string]any

skills/basecamp/SKILL.md

@@ -562,6 +562,8 @@ basecamp checkins --in <project> --json           # Questionnaire info
 basecamp checkins questions --in <project>        # List questions
 basecamp checkins question <id> --in <project>    # Question details
 basecamp checkins answers <question_id> --in <project>  # List answers
+basecamp checkins answers <question_id> --by me --in <project>  # My answers only
+basecamp checkins answers <question_id> --by "Alice Smith" --in <project>  # Filter by person (name, email, or ID)
 basecamp checkins answer <id> --in <project>      # Answer details
 basecamp checkins question create "What did you work on?" --in <project>
 basecamp checkins question update <id> "New question" --frequency every_week