src/__tests__/model_selection.spec.ts

@@ -0,0 +1,99 @@
+/**
+ * Tests for the localStorage-backed model selection persistence helper.
+ * jsdom provides a real (per-test-class) localStorage.
+ */
+import {
+  clearModelSelection,
+  loadModelSelection,
+  saveModelSelection
+} from '../components/model_selection';
+
+describe('loadModelSelection', () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  it('returns null when no entry exists', () => {
+    expect(loadModelSelection('foo.ipynb')).toBeNull();
+  });
+
+  it('returns null for an empty notebookPath (defensive)', () => {
+    expect(loadModelSelection('')).toBeNull();
+  });
+
+  it('returns the parsed entry when storage is valid', () => {
+    localStorage.setItem(
+      'opencode_bridge:model-selection:foo.ipynb',
+      JSON.stringify({ providerId: 'anthropic', modelId: 'claude-sonnet-4-20250514' })
+    );
+    expect(loadModelSelection('foo.ipynb')).toEqual({
+      providerId: 'anthropic',
+      modelId: 'claude-sonnet-4-20250514'
+    });
+  });
+
+  it('returns null for malformed JSON (does not throw)', () => {
+    localStorage.setItem(
+      'opencode_bridge:model-selection:foo.ipynb',
+      '{not json'
+    );
+    expect(loadModelSelection('foo.ipynb')).toBeNull();
+  });
+
+  it('returns null when the entry is missing required fields', () => {
+    localStorage.setItem(
+      'opencode_bridge:model-selection:foo.ipynb',
+      JSON.stringify({ providerId: 'anthropic' })
+    );
+    expect(loadModelSelection('foo.ipynb')).toBeNull();
+  });
+
+  it('keys entries independently per notebookPath', () => {
+    saveModelSelection('a.ipynb', { providerId: 'p1', modelId: 'm1' });
+    saveModelSelection('b.ipynb', { providerId: 'p2', modelId: 'm2' });
+    expect(loadModelSelection('a.ipynb')).toEqual({
+      providerId: 'p1',
+      modelId: 'm1'
+    });
+    expect(loadModelSelection('b.ipynb')).toEqual({
+      providerId: 'p2',
+      modelId: 'm2'
+    });
+  });
+});
+
+describe('saveModelSelection + clearModelSelection', () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  it('writes a JSON entry that can be re-read', () => {
+    saveModelSelection('foo.ipynb', { providerId: 'p1', modelId: 'm1' });
+    expect(loadModelSelection('foo.ipynb')).toEqual({
+      providerId: 'p1',
+      modelId: 'm1'
+    });
+  });
+
+  it('overwrites an existing entry', () => {
+    saveModelSelection('foo.ipynb', { providerId: 'p1', modelId: 'm1' });
+    saveModelSelection('foo.ipynb', { providerId: 'p2', modelId: 'm2' });
+    expect(loadModelSelection('foo.ipynb')).toEqual({
+      providerId: 'p2',
+      modelId: 'm2'
+    });
+  });
+
+  it('clearModelSelection removes the entry', () => {
+    saveModelSelection('foo.ipynb', { providerId: 'p1', modelId: 'm1' });
+    clearModelSelection('foo.ipynb');
+    expect(loadModelSelection('foo.ipynb')).toBeNull();
+  });
+
+  it('no-op for an empty notebookPath (defensive)', () => {
+    expect(() =>
+      saveModelSelection('', { providerId: 'p1', modelId: 'm1' })
+    ).not.toThrow();
+    expect(() => clearModelSelection('')).not.toThrow();
+  });
+});

src/__tests__/opencode_cell_actions.spec.ts

@@ -103,6 +103,12 @@ beforeAll(() => {
   });
 });
 
+beforeEach(() => {
+  // Each test starts with a clean selection store so persistence tests
+  // are deterministic.
+  localStorage.clear();
+});
+
 // Mock the network-touching API module so jsdom tests don't try to hit
 // a real notebook server (and to keep the refresh-history logic decoupled
 // from the network). The cell_actions tests focus on widget behavior.
@@ -323,6 +329,122 @@ describe('OpenCodeCellActions', () => {
     setOpenCodeProviders(null);
   });
 
+  it('restores the user\'s previously-saved (provider, model) when still valid in the providers payload', () => {
+    // Seed localStorage with a prior selection that IS valid.
+    localStorage.setItem(
+      'opencode_bridge:model-selection:foo.ipynb',
+      JSON.stringify({ providerId: 'openai', modelId: 'gpt-5' })
+    );
+    setOpenCodeProviders({
+      providers: [
+        { id: 'anthropic', models: { 'claude-sonnet-4-20250514': { id: 'x' } } },
+        { id: 'openai', models: { 'gpt-5': { id: 'x' }, 'gpt-4': { id: 'x' } } }
+      ],
+      default: { anthropic: 'claude-sonnet-4-20250514' }
+    });
+    const cell = makeFakeCell('x = 1', [], 'foo.ipynb');
+    const actions = new OpenCodeCellActions(cell);
+    Object.defineProperty(actions, 'parent', { value: cell, configurable: true });
+    (actions as any).onAfterAttach({} as any);
+
+    (actions.node.querySelector('button') as HTMLButtonElement).click();
+    const prompt = (actions as any)._prompt;
+    const providerSel = prompt.node.querySelector(
+      '.opencode-provider-select'
+    ) as HTMLSelectElement;
+    const modelSel = prompt.node.querySelector(
+      '.opencode-model-select'
+    ) as HTMLSelectElement;
+    // Stored selection was applied, NOT the default (first provider).
+    expect(providerSel.value).toBe('openai');
+    expect(modelSel.value).toBe('gpt-5');
+    setOpenCodeProviders(null);
+  });
+
+  it('falls back to default when the stored provider is no longer present', () => {
+    localStorage.setItem(
+      'opencode_bridge:model-selection:foo.ipynb',
+      JSON.stringify({ providerId: 'removed-provider', modelId: 'm1' })
+    );
+    setOpenCodeProviders({
+      providers: [
+        { id: 'anthropic', models: { 'claude-sonnet-4-20250514': { id: 'x' } } }
+      ]
+    });
+    const cell = makeFakeCell('x = 1', [], 'foo.ipynb');
+    const actions = new OpenCodeCellActions(cell);
+    Object.defineProperty(actions, 'parent', { value: cell, configurable: true });
+    (actions as any).onAfterAttach({} as any);
+
+    (actions.node.querySelector('button') as HTMLButtonElement).click();
+    const providerSel = (actions as any)._prompt.node.querySelector(
+      '.opencode-provider-select'
+    ) as HTMLSelectElement;
+    // Provider is gone → fall back to first available.
+    expect(providerSel.value).toBe('anthropic');
+    setOpenCodeProviders(null);
+  });
+
+  it('falls back to default model when the stored model is no longer present under the same provider', () => {
+    localStorage.setItem(
+      'opencode_bridge:model-selection:foo.ipynb',
+      JSON.stringify({ providerId: 'openai', modelId: 'gpt-99-removed' })
+    );
+    setOpenCodeProviders({
+      providers: [
+        { id: 'openai', models: { 'gpt-5': { id: 'x' }, 'gpt-4': { id: 'x' } } }
+      ],
+      default: { openai: 'gpt-5' }
+    });
+    const cell = makeFakeCell('x = 1', [], 'foo.ipynb');
+    const actions = new OpenCodeCellActions(cell);
+    Object.defineProperty(actions, 'parent', { value: cell, configurable: true });
+    (actions as any).onAfterAttach({} as any);
+
+    (actions.node.querySelector('button') as HTMLButtonElement).click();
+    const modelSel = (actions as any)._prompt.node.querySelector(
+      '.opencode-model-select'
+    ) as HTMLSelectElement;
+    // Model is gone → fall back to default[openai] = gpt-5.
+    expect(modelSel.value).toBe('gpt-5');
+    setOpenCodeProviders(null);
+  });
+
+  it('saves the new selection to localStorage when the model select changes', () => {
+    setOpenCodeProviders({
+      providers: [
+        { id: 'anthropic', models: { 'claude-sonnet-4-20250514': { id: 'x' } } },
+        { id: 'openai', models: { 'gpt-5': { id: 'x' } } }
+      ]
+    });
+    const cell = makeFakeCell('x = 1', [], 'foo.ipynb');
+    const actions = new OpenCodeCellActions(cell);
+    Object.defineProperty(actions, 'parent', { value: cell, configurable: true });
+    (actions as any).onAfterAttach({} as any);
+
+    (actions.node.querySelector('button') as HTMLButtonElement).click();
+    const prompt = (actions as any)._prompt;
+    const providerSel = prompt.node.querySelector(
+      '.opencode-provider-select'
+    ) as HTMLSelectElement;
+    const modelSel = prompt.node.querySelector(
+      '.opencode-model-select'
+    ) as HTMLSelectElement;
+
+    // Switch provider to openai (whose model list includes gpt-5).
+    providerSel.value = 'openai';
+    providerSel.dispatchEvent(new Event('change'));
+    // Now change the model select to gpt-5.
+    modelSel.value = 'gpt-5';
+    modelSel.dispatchEvent(new Event('change'));
+
+    const stored = JSON.parse(
+      localStorage.getItem('opencode_bridge:model-selection:foo.ipynb') || 'null'
+    );
+    expect(stored).toEqual({ providerId: 'openai', modelId: 'gpt-5' });
+    setOpenCodeProviders(null);
+  });
+
   it('falls back to the first model when default[provider] is not in models', () => {
     setOpenCodeProviders({
       providers: [

src/components/model_selection.ts

@@ -0,0 +1,82 @@
+/**
+ * Persistence of the user's (provider, model) selection in the inline
+ * prompt, keyed by notebook path. Stored in localStorage so the
+ * preference survives panel close/reopen and JupyterLab restart.
+ *
+ * The selection is ALWAYS validated against the current providers
+ * payload before being applied: if the stored provider (or the model
+ * under it) is no longer present, the caller falls back to its
+ * default-selection logic. We never silently apply a stale value that
+ * would result in an empty / disabled <select>.
+ *
+ * Storage is best-effort: localStorage may be disabled (private mode),
+ * the quota may be exhausted, or the value may be corrupt. All
+ * failure modes return null / no-op rather than throw.
+ */
+const STORAGE_PREFIX = 'opencode_bridge:model-selection:';
+
+export interface ModelSelection {
+  providerId: string;
+  modelId: string;
+}
+
+export function loadModelSelection(notebookPath: string): ModelSelection | null {
+  if (!notebookPath) {
+    return null;
+  }
+  try {
+    if (typeof localStorage === 'undefined') {
+      return null;
+    }
+    const raw = localStorage.getItem(STORAGE_PREFIX + notebookPath);
+    if (!raw) {
+      return null;
+    }
+    const parsed = JSON.parse(raw);
+    if (
+      parsed &&
+      typeof parsed === 'object' &&
+      typeof (parsed as ModelSelection).providerId === 'string' &&
+      typeof (parsed as ModelSelection).modelId === 'string'
+    ) {
+      return {
+        providerId: (parsed as ModelSelection).providerId,
+        modelId: (parsed as ModelSelection).modelId
+      };
+    }
+    return null;
+  } catch {
+    return null;
+  }
+}
+
+export function saveModelSelection(
+  notebookPath: string,
+  sel: ModelSelection
+): void {
+  if (!notebookPath) {
+    return;
+  }
+  try {
+    if (typeof localStorage === 'undefined') {
+      return;
+    }
+    localStorage.setItem(STORAGE_PREFIX + notebookPath, JSON.stringify(sel));
+  } catch {
+    // Ignore quota exceeded / disabled storage.
+  }
+}
+
+export function clearModelSelection(notebookPath: string): void {
+  if (!notebookPath) {
+    return;
+  }
+  try {
+    if (typeof localStorage === 'undefined') {
+      return;
+    }
+    localStorage.removeItem(STORAGE_PREFIX + notebookPath);
+  } catch {
+    // ignore
+  }
+}

src/components/opencode_cell_actions.ts

@@ -127,6 +127,7 @@ export class OpenCodeCellActions extends Widget {
     const prompt = new OpenCodeInlinePrompt(this._cell, {
       disabled: !this._context || this._status === 'loading',
       providers: _providers,
+      notebookPath: this._context?.notebookPath,
       onSubmit: (text: string, providerId?: string, modelId?: string) => {
         void this._onSubmit(text, providerId, modelId);
       },

src/components/opencode_inline_prompt.ts

@@ -30,12 +30,23 @@ import type {
   OpenCodeMessage,
   OpenCodeProvidersResponse
 } from '../types';
+import {
+  loadModelSelection,
+  saveModelSelection
+} from './model_selection';
 
 export interface IOpenCodeInlinePromptOptions {
   onSubmit: (text: string, providerId?: string, modelId?: string) => void;
   onCancel: () => void;
   disabled: boolean;
   providers: OpenCodeProvidersResponse | null;
+  /**
+   * Notebook path used to key the persisted (provider, model) selection
+   * in localStorage. If omitted (or the stored selection is no longer
+   * valid in the current `providers` payload), the prompt falls back
+   * to the default selection (first provider / `default[pid]` model).
+   */
+  notebookPath?: string;
   /**
    * Respond to a `permission.asked` event. Returns a promise that resolves
    * to true on success, false on failure (the prompt updates the UI in
@@ -143,6 +154,12 @@ export class OpenCodeInlinePrompt extends Widget {
     this._providerModels = flat.providers;
     this._defaultMap = flat.defaultMap;
 
+    // Resolve the initial selection: prefer a previously-saved
+    // (providerId, modelId) IF it's still valid in the current
+    // providers payload; otherwise fall back to the default
+    // (first provider / `default[pid]` model).
+    const stored = this._resolveStoredSelection(options.notebookPath);
+
     if (this._providerModels.length > 0) {
       this._providerSelect = document.createElement('select');
       this._providerSelect.className = 'opencode-provider-select';
@@ -152,16 +169,25 @@ export class OpenCodeInlinePrompt extends Widget {
         o.textContent = p.name ? `${p.id} (${p.name})` : p.id;
         this._providerSelect.appendChild(o);
       }
-      this._providerSelect.value = this._providerModels[0].id;
+      this._providerSelect.value = stored
+        ? stored.providerId
+        : this._providerModels[0].id;
       this._providerSelect.addEventListener('change', () => {
         this._rebuildModelSelect(this._providerSelect!.value);
+        this._persistSelection();
       });
     }
 
     if (this._providerModels.length > 0) {
       this._modelSelect = document.createElement('select');
       this._modelSelect.className = 'opencode-model-select';
-      this._rebuildModelSelect(this._providerSelect?.value);
+      this._rebuildModelSelect(
+        this._providerSelect?.value,
+        stored ? stored.modelId : undefined
+      );
+      this._modelSelect.addEventListener('change', () => {
+        this._persistSelection();
+      });
     }
 
     this._textarea = document.createElement('textarea');
@@ -230,7 +256,10 @@ export class OpenCodeInlinePrompt extends Widget {
     this.node.appendChild(actions);
   }
 
-  private _rebuildModelSelect(providerId: string | undefined): void {
+  private _rebuildModelSelect(
+    providerId: string | undefined,
+    preferredModelId?: string
+  ): void {
     if (!this._modelSelect) {
       return;
     }
@@ -258,8 +287,65 @@ export class OpenCodeInlinePrompt extends Widget {
       this._modelSelect.appendChild(o);
     }
     this._modelSelect.disabled = false;
+    // Honor a preferred model (e.g. from a stored selection), but only
+    // if it actually exists in this provider's model list. Otherwise
+    // fall back to the default.
+    if (
+      preferredModelId &&
+      Object.prototype.hasOwnProperty.call(provider.models, preferredModelId)
+    ) {
+      this._modelSelect.value = preferredModelId;
+    } else {
       this._modelSelect.value =
-      pickDefaultModelId(providerId, provider.models, this._defaultMap) ?? keys[0];
+        pickDefaultModelId(providerId, provider.models, this._defaultMap) ??
+        keys[0];
+    }
+  }
+
+  /**
+   * Read the stored (providerId, modelId) for this notebook and
+   * validate it against the current providers payload. Returns the
+   * stored selection only when BOTH the provider and the model still
+   * exist; otherwise returns null and the caller uses the default.
+   */
+  private _resolveStoredSelection(
+    notebookPath: string | undefined
+  ): { providerId: string; modelId: string } | null {
+    if (!notebookPath) {
+      return null;
+    }
+    const sel = loadModelSelection(notebookPath);
+    if (!sel) {
+      return null;
+    }
+    const provider = this._providerModels.find(p => p.id === sel.providerId);
+    if (!provider) {
+      // The provider was removed since the user last picked.
+      return null;
+    }
+    if (!Object.prototype.hasOwnProperty.call(provider.models, sel.modelId)) {
+      // The model was removed (or renamed) under a still-valid provider.
+      return null;
+    }
+    return sel;
+  }
+
+  /**
+   * Persist the current (providerSelect.value, modelSelect.value) for
+   * this notebook. No-op if the prompt has no notebookPath, no
+   * selects, or the values are empty.
+   */
+  private _persistSelection(): void {
+    const notebookPath = this._options.notebookPath;
+    if (!notebookPath || !this._providerSelect || !this._modelSelect) {
+      return;
+    }
+    const providerId = this._providerSelect.value;
+    const modelId = this._modelSelect.value;
+    if (!providerId || !modelId) {
+      return;
+    }
+    saveModelSelection(notebookPath, { providerId, modelId });
   }
 
   setDisabled(disabled: boolean): void {