Structured missing-arg errors for agent elicitation

.surface

@@ -1505,7 +1505,6 @@ FLAG basecamp checkins answer create --no-hints type=bool
 FLAG basecamp checkins answer create --no-stats type=bool
 FLAG basecamp checkins answer create --profile type=string
 FLAG basecamp checkins answer create --project type=string
-FLAG basecamp checkins answer create --question type=string
 FLAG basecamp checkins answer create --questionnaire type=string
 FLAG basecamp checkins answer create --quiet type=bool
 FLAG basecamp checkins answer create --stats type=bool
@@ -6035,7 +6034,6 @@ FLAG basecamp webhooks create --stats type=bool
 FLAG basecamp webhooks create --styled type=bool
 FLAG basecamp webhooks create --todolist type=string
 FLAG basecamp webhooks create --types type=string
-FLAG basecamp webhooks create --url type=string
 FLAG basecamp webhooks create --verbose type=count
 FLAG basecamp webhooks delete --account type=string
 FLAG basecamp webhooks delete --agent type=bool

.surface-breaking

@@ -0,0 +1,4 @@
+FLAG basecamp checkin answer create --question type=string
+FLAG basecamp checkins answer create --question type=string
+FLAG basecamp webhook create --url type=string
+FLAG basecamp webhooks create --url type=string

e2e/boost.bats

@@ -12,7 +12,8 @@ load test_helper
 
   run basecamp react "👍"
   assert_failure
-  assert_output_contains "--on or --recording required"
+  assert_json_value '.error' '--on or --recording required'
+  assert_json_value '.code' 'usage'
 }
 
 

e2e/campfire.bats

@@ -51,7 +51,8 @@ load test_helper
 
   run basecamp campfire post
   assert_failure
-  assert_output_contains "Message content required"
+  assert_json_value '.error' '<message> required'
+  assert_json_value '.code' 'usage'
 }
 
 
@@ -129,14 +130,13 @@ load test_helper
 
 # Unknown action - Cobra treats unknown args as command arguments, not subcommands
 
-@test "campfire unknown action shows error" {
+@test "campfire unknown action shows help" {
   create_credentials
   create_global_config '{"account_id": 99999}'
 
   run basecamp campfire foobar
-  # Cobra doesn't have a distinct "unknown subcommand" error for this pattern
-  # It falls through to the default behavior which requires a project
-  assert_failure
+  # Parent command with no RunE — cobra shows help for unknown subcommands
+  assert_success
 }
 
 

e2e/cards_columns_steps.bats

@@ -6,31 +6,32 @@ load test_helper
 
 # Card create tests
 
-@test "card --help shows help with --content option" {
+@test "card --help shows help with positional args" {
   create_credentials
   create_global_config '{"account_id": 99999}'
 
   run basecamp card --help
   assert_success
   assert_output_contains "basecamp card"
-  assert_output_contains "--content"
-  assert_output_contains "--title"
+  assert_output_contains "<title>"
 }
 
-@test "card --content without value shows error" {
+@test "card --content is not a valid flag" {
   create_credentials
   create_global_config '{"account_id": 99999, "project_id": 123}'
 
-  run basecamp card --title "Test" --content
+  # Content is now a positional arg, not a flag
+  run basecamp card "Test" --content
   assert_failure
-  assert_output_contains "--content requires a value"
+  assert_output_contains "Unknown option"
 }
 
 @test "card with unknown option shows error" {
   create_credentials
   create_global_config '{"account_id": 99999, "project_id": 123}'
 
-  run basecamp card --title "Test" --foo
+  # Title is now positional, not --title
+  run basecamp card "Test" --foo
   assert_failure
   assert_output_contains "Unknown option: --foo"
 }
@@ -39,9 +40,10 @@ load test_helper
   create_credentials
   create_global_config '{"account_id": 99999, "project_id": 123}'
 
-  run basecamp card --content "Body only"
+  run basecamp card
   assert_failure
-  assert_output_contains "title required"
+  assert_json_value '.error' '<title> required'
+  assert_json_value '.code' 'usage'
 }
 
 
@@ -74,7 +76,8 @@ load test_helper
 
   run basecamp cards column create
   assert_failure
-  assert_output_contains "title required"
+  assert_json_value '.error' '<title> required'
+  assert_json_value '.code' 'usage'
 }
 
 
@@ -179,7 +182,8 @@ load test_helper
 
   run basecamp cards column color 456
   assert_failure
-  assert_output_contains "--color is required"
+  assert_json_value '.error' '--color required'
+  assert_json_value '.code' 'usage'
 }
 
 
@@ -234,7 +238,7 @@ load test_helper
 
   run basecamp cards steps
   assert_failure
-  assert_output_contains "ID required"
+  assert_output_contains "required"
 }
 
 @test "cards steps without project shows error" {
@@ -255,7 +259,8 @@ load test_helper
 
   run basecamp cards step create --card 456
   assert_failure
-  assert_output_contains "title required"
+  assert_json_value '.error' '<title> required'
+  assert_json_value '.code' 'usage'
 }
 
 @test "cards step create without card shows error" {
@@ -277,7 +282,8 @@ load test_helper
 
   run basecamp cards step update
   assert_failure
-  assert_output_contains "ID required"
+  assert_json_value '.error' '<step_id|url> required'
+  assert_json_value '.code' 'usage'
 }
 
 @test "cards step update without fields shows error" {
@@ -328,7 +334,8 @@ load test_helper
 
   run basecamp cards step move 456 --position 1
   assert_failure
-  assert_output_contains "--card is required"
+  assert_json_value '.error' '--card required'
+  assert_json_value '.code' 'usage'
 }
 
 @test "cards step move without position shows error" {

e2e/checkins.bats

@@ -27,13 +27,13 @@ load test_helper
 
 # Missing context errors
 
-@test "checkins without project shows error" {
+@test "checkins without subcommand shows help" {
   create_credentials
   create_global_config '{"account_id": 99999}'
 
   run basecamp checkins
-  assert_failure
-  assert_output_contains "project"
+  assert_success
+  assert_output_contains "COMMANDS"
 }
 
 @test "checkins questions without project shows error" {
@@ -51,7 +51,8 @@ load test_helper
 
   run basecamp checkins question
   assert_failure
-  assert_output_contains "ID required"
+  assert_json_value '.error' '<id|url> required'
+  assert_json_value '.code' 'usage'
 }
 
 @test "checkins answers without question id shows error" {
@@ -69,7 +70,8 @@ load test_helper
 
   run basecamp checkins answer
   assert_failure
-  assert_output_contains "Answer ID required"
+  assert_json_value '.error' '<id|url> required'
+  assert_json_value '.code' 'usage'
 }