feat(agents): align duplicate create errors

docs/CHATWOOT_PARITY_DEVELOPMENT_PLAN.md

@@ -16,10 +16,10 @@ Build GoChat as a Go backend that can directly reuse the frontend from `referenc
 
 ## Current Baseline
 
-- Current tracking checkpoint: 2026-06-06 after `3c30596 feat(attachments): align list pagination`, with this implementation checkpoint prepared as `feat(agents): align create name defaults`.
-- Latest implementation checkpoint: this checkpoint, prepared as `feat(agents): align create name defaults`.
+- Current tracking checkpoint: 2026-06-06 after `dd2bdee feat(agents): align create name defaults`, with this implementation checkpoint prepared as `feat(agents): align duplicate create errors`.
+- Latest implementation checkpoint: this checkpoint, prepared as `feat(agents): align duplicate create errors`.
 - Latest documentation-only checkpoint: `8b378c7 docs: refresh parity tracker baseline`; this document is now the active follow-up plan and supersedes `.hermes/plans/*`.
-- Worktree status at this implementation checkpoint: Agent creation now matches Chatwoot `AgentBuilder` name fallback: blank or omitted `agent[name]` no longer fails local validation and new users receive the email local-part as `name`. Account conversation/contact attachment list pagination already matches Chatwoot's fixed 100-row page size for `ConversationsController#attachments` and `Contacts::AttachmentsController#index`; reused frontend `per_page` query values no longer shrink shared attachment payloads below the reference page size. Profile account permission drift is closed for reused route guards and dashboard permission helpers: profile account entries now return Chatwoot `AccountUser#permissions` for ordinary roles (`["administrator"]` or `["agent"]`) and continue to return enterprise custom-role permissions plus `custom_role` when `custom_role_id` is present. The preceding platform account-user membership, agents list ordering, update-route/`auto_offline`, agents bulk invite, B10.3 CustomRole frontend update, and Phase 6 contacts pagination/active payload drifts are closed. Conversation transcript and custom-attribute response drifts are already closed. The fresh placeholder audit found remaining `chatwootParityStub` routes only in webhook handler-not-injected fallbacks, not in the reused dashboard account/contact/conversation/message/inbox critical path. P3.6 custom filters/custom attribute definitions and label CRUD are already in Review. B11.1a-B11.3e Captain/Copilot slices remain in Review; B12.1/B12.2/B12.3 smoke harnesses remain in Review; P5 durable job work through P5.13b is in Review. Next active implementation slice is the next named Phase 2/3 or Phase 6 drift from fresh reference/smoke evidence.
+- Worktree status at this implementation checkpoint: Duplicate account agent creation now matches Chatwoot's `ActiveRecord::RecordInvalid` response shape: `422` with `{ message, attributes }` instead of a local `409` envelope. Agent creation already matches Chatwoot `AgentBuilder` name fallback: blank or omitted `agent[name]` no longer fails local validation and new users receive the email local-part as `name`. Account conversation/contact attachment list pagination already matches Chatwoot's fixed 100-row page size for `ConversationsController#attachments` and `Contacts::AttachmentsController#index`; reused frontend `per_page` query values no longer shrink shared attachment payloads below the reference page size. Profile account permission drift is closed for reused route guards and dashboard permission helpers: profile account entries now return Chatwoot `AccountUser#permissions` for ordinary roles (`["administrator"]` or `["agent"]`) and continue to return enterprise custom-role permissions plus `custom_role` when `custom_role_id` is present. The preceding platform account-user membership, agents list ordering, update-route/`auto_offline`, agents bulk invite, B10.3 CustomRole frontend update, and Phase 6 contacts pagination/active payload drifts are closed. Conversation transcript and custom-attribute response drifts are already closed. The fresh placeholder audit found remaining `chatwootParityStub` routes only in webhook handler-not-injected fallbacks, not in the reused dashboard account/contact/conversation/message/inbox critical path. P3.6 custom filters/custom attribute definitions and label CRUD are already in Review. B11.1a-B11.3e Captain/Copilot slices remain in Review; B12.1/B12.2/B12.3 smoke harnesses remain in Review; P5 durable job work through P5.13b is in Review. Next active implementation slice is the next named Phase 2/3 or Phase 6 drift from fresh reference/smoke evidence.
 - `go test ./...` passes.
 - Route dump succeeds with `TOTAL: 840` after adding the Chatwoot platform account-user collection destroy route.
 - Route parity artifacts now exist under `docs/parity/` and are generated by `cmd/route_parity`.
@@ -87,7 +87,7 @@ This table is the shortest authoritative handoff view. If an older lower section
 
 | Priority | Workstream | Current state | Next checkpoint | Commit close rule |
 | --- | --- | --- | --- | --- |
-| 1 | Phase 2/3 drift | Tracked route parity is 0 missing for the current critical set; notification list/action serializers, Devise password reset/confirmation payloads, CRM shared attachment payloads plus fixed 100-row attachment pagination, account/settings payloads, assignable-agent payloads, agent create defaults, label CRUD payloads, custom filters, and custom attribute definitions now match the inspected Chatwoot frontend contract. | Continue Phase 6 placeholder audit, then open the next named serializer/controller drift slice from reference/smoke evidence. | Regenerate parity artifacts when routes change and add endpoint-family fixture tests. |
+| 1 | Phase 2/3 drift | Tracked route parity is 0 missing for the current critical set; notification list/action serializers, Devise password reset/confirmation payloads, CRM shared attachment payloads plus fixed 100-row attachment pagination, account/settings payloads, assignable-agent payloads, agent create defaults/errors, label CRUD payloads, custom filters, and custom attribute definitions now match the inspected Chatwoot frontend contract. | Continue Phase 6 placeholder audit, then open the next named serializer/controller drift slice from reference/smoke evidence. | Regenerate parity artifacts when routes change and add endpoint-family fixture tests. |
 | 2 | Phase 6 placeholder audit | Widget/public/webhook critical placeholders are burned down; inbox WhatsApp health/register-webhook and sync-template drift are closed; fresh `rg` audit shows only webhook nil-handler fallbacks still call `chatwootParityStub`; dashboard conversation transcript response drift is closed. | Continue targeted account/contact/conversation/message/inbox drift from reference/smoke evidence. | `rg` placeholder audit is recorded and no reused-frontend blocker is ownerless. |
 | 3 | B12 optional live smoke | API/browser/enterprise smoke commands are checked in; live runs need PostgreSQL, Redis, Meilisearch, Vite, and Chrome. | Run full live smoke when environment is available and map failures to the board. | `docs/parity/frontend_smoke_report.md` records pass/fail and linked owners. |
 | 4 | B9.3 delayed automation actions | Current reference exposes no delayed automation action params; scheduled-item work is already P5.12; `send_email_to_team` is durable and `add_sla` mutates conversation/applied SLA state. | Keep automation drift closed if future reference/smoke exposes delayed params or unsupported action shapes. | Automation worker/action fixtures verify queued team email replay, retry visibility through worker jobs, and SLA action idempotency. |
@@ -143,6 +143,7 @@ This ledger records the committed parity checkpoints that future slices should b
 
 | Commit | Scope | Verification summary | Follow-up state |
 | --- | --- | --- | --- |
+| `feat(agents): align duplicate create errors` | Advances P3.2 agents/settings parity by matching Chatwoot's `ActiveRecord::RecordInvalid` handling for duplicate account memberships created through `AgentsController#create`. Re-inviting an existing account member now returns `422 { message: "User has already been taken", attributes: ["user_id"] }` instead of the local `409` conflict envelope, while bulk invite continues to skip duplicate failures like the reference controller. | `go test ./internal/handler/api/v1 -run 'TestAgentHandlerSuite/TestCreateAgentDuplicate' -count=1`; `go test ./internal/handler/api/v1 ./internal/service ./internal/repository -count=1`; `go test ./...`; `git diff --check`. No route changes; route dump remains `TOTAL: 840`. | Continue P3.2 agents/account-user drift or the next Phase 6 reference/smoke finding. |
 | `feat(agents): align create name defaults` | Advances P3.2 agents/settings parity by matching Chatwoot `AgentsController#create` and `AgentBuilder`. Agent creation now accepts blank or omitted `agent[name]`; for newly created users, the name falls back to the email local-part exactly like `email.split('@').first`, while existing-user invitation behavior remains unchanged. | `go test ./internal/handler/api/v1 -run 'TestAgentHandlerSuite/TestCreateAgent' -count=1`; `go test ./internal/service ./internal/repository -run Agent -count=1`; `go test ./internal/handler/api/v1 ./internal/service ./internal/repository -count=1`; `go test ./...`; `git diff --check`. No route changes; route dump remains `TOTAL: 840`. | Continue P3.2 agents/account-user drift or the next Phase 6 reference/smoke finding. |
 | `feat(attachments): align list pagination` | Advances Phase 6 dashboard/CRM attachment drift by matching Chatwoot `ConversationsController#attachments`, `Contacts::AttachmentsController#index`, and the shared attachment Jbuilder payloads. Conversation and contact attachment lists now page with the reference fixed 100-row limit from `ATTACHMENT_RESULTS_PER_PAGE`/`RESULTS_PER_PAGE` and ignore reused-frontend `per_page` query values, while retaining newest-first attachment ordering and `{ meta: { total_count }, payload }` responses. | `go test ./internal/handler/api/v1 -run 'Test(ConversationHandlerTestSuite|ContactHandlerCRUDTestSuite)/TestListAttachments' -count=1`; `go test ./internal/handler/api/v1 ./internal/service ./internal/repository -count=1`; `go test ./...`; `git diff --check`. No route changes; route dump remains `TOTAL: 840`. | Continue the next named Phase 2/3 or Phase 6 drift from reference/smoke evidence. |
 | `feat(profile): align account permissions` | Advances P3.1/P3.2 profile and permission parity by matching Chatwoot `api/v1/models/_user.json.jbuilder`, `AccountUser#permissions`, and the enterprise custom-role prepend used by dashboard route guards. Profile account entries now expose ordinary role permissions as `["administrator"]` or `["agent"]`, and custom-role memberships expose the role's permission keys plus `custom_role` while retaining nested `custom_role` metadata. | `go test ./internal/handler/api/v1 -run ProfileHandler -count=1`; `go test ./internal/handler/api/v1 ./internal/service ./internal/repository -count=1`; `go test ./...`; `git diff --check`. No route changes; route dump remains `TOTAL: 840`. | Continue P3.2 permissions/invitations drift or the next Phase 6 reference/smoke finding. |
@@ -2079,6 +2080,7 @@ Verification milestone gates:
 
 ## Progress Log
 
+- 2026-06-06: P3.2 agent duplicate-create checkpoint prepared as `feat(agents): align duplicate create errors`; audited Chatwoot `AgentsController#create`, `AgentBuilder#create_account_user`, `AccountUser` uniqueness validation, and `RequestExceptionHandler#render_record_invalid`. Duplicate account membership creation through `/agents` now returns Chatwoot `422 { message, attributes }` instead of local `409`, while bulk invite duplicate skipping remains unchanged. Focused duplicate-create tests, combined handler/service/repository tests, full `go test ./...`, and `git diff --check` passed; continue P3.2 agents/account-user drift or the next Phase 6 reference/smoke finding.
 - 2026-06-06: P3.2 agent create-default checkpoint prepared as `feat(agents): align create name defaults`; audited Chatwoot `AgentsController#create`, `AgentBuilder`, `AccountUser`, and the reused dashboard agents API. Agent creation now accepts blank/omitted `agent[name]`, derives new-user names from the email local-part like `email.split('@').first`, and keeps existing agent create role/availability/auto-offline behavior intact. Focused agent create tests, service/repository agent tests, combined handler/service/repository tests, full `go test ./...`, and `git diff --check` passed; continue P3.2 agents/account-user drift or the next Phase 6 reference/smoke finding.
 - 2026-06-06: Phase 6 attachment pagination checkpoint prepared as `feat(attachments): align list pagination`; audited Chatwoot `ConversationsController#attachments`, `Contacts::AttachmentsController#index`, and the shared attachment Jbuilder partials. Conversation and contact shared attachment lists now use Chatwoot's fixed 100-row page size and ignore `per_page` query values, preserving `{ meta: { total_count }, payload }`, newest-first ordering, sender serialization, and contact attachment `conversation_id`. Focused attachment suite tests, combined handler/service/repository tests, full `go test ./...`, and `git diff --check` passed; continue the next Phase 2/3 or Phase 6 drift from reference/smoke evidence.
 - 2026-06-06: P3.1/P3.2 profile permissions checkpoint prepared as `feat(profile): align account permissions`; audited Chatwoot `_user.json.jbuilder`, `AccountUser#permissions`, enterprise `Enterprise::AccountUser`, and dashboard `permissionsHelper.js`. Profile account entries now expose `["administrator"]`/`["agent"]` for ordinary roles and custom-role permission keys plus `custom_role` for custom-role memberships, preserving nested custom-role metadata for the reused frontend. Focused profile tests, combined handler/service/repository tests, full `go test ./...`, and `git diff --check` passed; continue P3.2 permissions/invitations drift next.

internal/handler/api/v1/agent_handler.go

@@ -111,7 +111,10 @@ func (h *AgentHandler) Create(c *gin.Context) {
 	agent, svcErr := h.svc.Create(c.Request.Context(), accountID, userID, req)
 	if svcErr != nil {
 		if errors.Is(svcErr, repository.ErrAlreadyMember) {
-			response.AbortWithStatusError(c, http.StatusConflict, response.ErrConflict, svcErr.Error())
+			c.JSON(http.StatusUnprocessableEntity, gin.H{
+				"message":    "User has already been taken",
+				"attributes": []string{"user_id"},
+			})
 			return
 		}
 		applogger.L().Errorf("Create agent for account %d: %v", accountID, svcErr)

internal/handler/api/v1/agent_handler_test.go

@@ -190,10 +190,14 @@ func (s *AgentHandlerTestSuite) TestCreateAgentDuplicate() {
 	s.handler.Create(c)
 	assert.Equal(s.T(), http.StatusOK, w.Code)
 
-	// Try creating again — should conflict
+	// Try creating again — Chatwoot renders ActiveRecord::RecordInvalid as 422.
 	w2, c2 := s.makeRequest("POST", "/api/v1/accounts/1/agents", req, s.account.ID, s.user.ID)
 	s.handler.Create(c2)
-	assert.Equal(s.T(), http.StatusConflict, w2.Code)
+	assert.Equal(s.T(), http.StatusUnprocessableEntity, w2.Code)
+	var data map[string]interface{}
+	json.Unmarshal(w2.Body.Bytes(), &data)
+	assert.Equal(s.T(), "User has already been taken", data["message"])
+	assert.Equal(s.T(), []interface{}{"user_id"}, data["attributes"])
 }
 
 func (s *AgentHandlerTestSuite) TestCreateAgentValidation() {