Plan: Fix silent failure when adding a Custom OpenAI-Compatible Provider (JetBrains)

Problem

In the JetBrains plugin, adding a "Custom OpenAI-Compatible Provider" can silently fail: the dialog closes with no error, the provider never appears in the list, and the user's typed inputs are gone. Reported against plugin 7.0.2.

Root causes

1. Zero-model providers are silently dropped by the CLI. The dialog only requires id and baseUrl; the models field is optional (ProvidersSettingsUi.kt:585 doValidate). The save really does write a provider.<id> block to config, but when the UI re-reads the provider list the CLI deletes any provider with no models (packages/opencode/src/provider/provider.ts:1667), and @ai-sdk/openai-compatible has no automatic model discovery. The provider is on disk but never rendered.

2. Errors are surfaced after the dialog is already closed. custom() (ProvidersSettingsUi.kt:216-227) calls dialog.showAndGet() (which closes the dialog), then runs the save and routes any error to the settings-panel overlay behind the closed dialog via apply(). On success with a dropped provider, saveCustom returns error = null, so even that overlay stays silent. Either way the typed inputs are lost and the user cannot correct and retry.

Goal

When saving a custom provider fails or the saved provider would not be usable, show the message inside the dialog, keep the dialog open with all inputs intact, and let the user fix and retry without re-typing. Prevent the zero-model silent-drop path entirely.

Design

Move the save into the dialog so it runs before the dialog closes:

• The dialog owns the save. It runs the RPC on the frontend coroutine scope, keeps itself open on failure, and shows the error via setErrorText(...). It only closes on a verified success.
• The settings panel consumes the final ProviderSettingsDto the dialog produced, so there is no second save.
• Require at least one model client-side and server-side, closing the zero-model drop path. Keep a post-save verification as a safety net for other silent drops.

RPC must never run on the EDT (doOKAction runs on EDT). The dialog launches on the existing cs scope and switches back to the EDT with ModalityState.any() for UI updates, matching the edt dispatcher already defined at ProvidersSettingsUi.kt:72.

Changes

1. frontend/.../settings/providers/ProvidersSettingsUi.kt

CustomProviderDialog (currently ProvidersSettingsUi.kt:542-590)

• Change the constructor to accept what it needs to save and report progress: CustomProviderDialog(cs: CoroutineScope, directory: String, save: suspend (CustomProviderSaveDto) -> ProviderActionResultDto). Pass save = { service<KiloProviderService>().saveCustom(it) } from custom() so the existing workspace-reload + profile-refresh side effects in KiloProviderService.action still run.
• Add a var outcome: ProviderSettingsDto? = null the panel reads after a successful close, and a saving guard to block double-submit (Enter while in-flight).
• Extend doValidate() to require at least one model:
  kotlinCopy

  if (models.text.split(',').none { it.isNotBlank() })
      return ValidationInfo(KiloBundle.message("settings.providers.customModelsRequired"), models)
  

• Override doOKAction() instead of letting the platform close on OK:
  • Return early if saving. Run doValidate(); if non-null, let the platform show it (do not close).
  • Set saving = true, disable the OK action (isOKActionEnabled = false), clear any previous error text.
  • cs.launch { val result = save(input(directory)); withContext(edt) { ... } }.
  • On the EDT, compute the inline error text (see helper below). If there is an error: setErrorText(text), isOKActionEnabled = true, saving = false, keep the dialog open. If success: store outcome = result.state, then super.doOKAction() to close.
  • Wrap the RPC in the same try/catch shape as launch() (ProvidersSettingsUi.kt:264-297): map TimeoutCancellationException and generic Exception to inline error text, rethrow CancellationException. No empty catch blocks.

Inline error helper (pure, testable)

Add a top-level internal fun customSaveError(id: String, result: ProviderActionResultDto): String?:

result.error?.let { return it }
val present = result.state.providers.any { it.id == id }
if (!present) return KiloBundle.message("settings.providers.customNotUsable")
return null

This is the safety net: even if validation passes, a provider that came back only in config but not in providers (the zero-model drop or an unreachable base URL) produces an inline message rather than a silent close.

custom() (ProvidersSettingsUi.kt:216-227)

Simplify to construct the dialog with the save lambda, and after a successful close apply the dialog's outcome to the panel (update state, view.update(next), clearProgress()), reusing the tail of apply(). The save no longer goes through launch(), which also removes the busy-gated silent return at ProvidersSettingsUi.kt:222/266.

2. backend/.../provider/KiloBackendProviderSettingsManager.kt

Extend validate() (:279-287) to reject empty models so the API is safe even when called outside the JetBrains dialog:

if (input.models.isEmpty()) return "At least one model ID is required."

This runs before any patch, so nothing is written to config on the empty-models path. No change needed to buildCustomProviderPatch.

3. frontend/.../resources/messages/KiloBundle.properties

Add message keys near the existing custom-provider strings (:470-477):

settings.providers.customModelsRequired=Add at least one model ID.
settings.providers.customNotUsable=Provider saved but has no usable models. Check the Base URL, API key, and model IDs, then try again.

Tests

Follow the JetBrains settings test pattern (fake-RPC frontend test + MockCliServer backend test). Do not mock the EDT or add test-only accessors.

Backend — backend/.../provider/KiloBackendProviderSettingsManagerTest.kt

• saveCustom with empty models returns a non-null error and issues no PATCH /global/config (assert against MockCliServer recorded requests).
• saveCustom with one model PATCHes the expected body, then a subsequent reload observes the provider in state.

Frontend — frontend/.../settings/providers/ProvidersSettingsUiTest.kt

• Unit-test the pure customSaveError helper: returns result.error when set; returns the not-usable message when the saved id is absent from state.providers; returns null when present.
• Extend FakeProviderRpcApi.saveCustom (already records custom) so a test can drive a configured ProviderActionResultDto (with/without the provider present) and assert the panel applies the returned state on success.

Verification

From packages/kilo-jetbrains/:

• ./gradlew typecheck
• ./gradlew test

Out of scope / follow-ups

• Wiring the already-implemented fetchCustomModels RPC (KiloProviderService.fetchCustomModels) into the dialog as a "Fetch models" button. This would improve UX further but is not required to fix the silent failure; track separately.
• Changing the CLI's zero-model drop in packages/opencode/src/provider/provider.ts is intentionally avoided — it is shared upstream code, and the fix above prevents the JetBrains client from ever reaching that path.