Add configurable OAuth storage backend and respect --models in model selector

- Add setOAuthStorage() and resetOAuthStorage() to pi-ai for custom storage backends
- Configure coding-agent to use its own configurable OAuth path via getOAuthPath()
- Model selector (/model command) now only shows models from --models scope when set
- Rewrite OAuth documentation in pi-ai README with examples

Fixes #255

packages/coding-agent/src/core/oauth/index.ts

@@ -13,15 +13,25 @@ import {
 	loginGitHubCopilot,
 	type OAuthCredentials,
 	type OAuthProvider,
+	type OAuthStorageBackend,
 	refreshToken as refreshTokenFromAi,
 	removeOAuthCredentials,
+	resetOAuthStorage,
 	saveOAuthCredentials,
+	setOAuthStorage,
 } from "@mariozechner/pi-ai";
 
 // Re-export types and functions
-export type { OAuthCredentials, OAuthProvider };
+export type { OAuthCredentials, OAuthProvider, OAuthStorageBackend };
 export { listOAuthProvidersFromAi as listOAuthProviders };
-export { getOAuthApiKey, loadOAuthCredentials, removeOAuthCredentials, saveOAuthCredentials };
+export {
+	getOAuthApiKey,
+	loadOAuthCredentials,
+	removeOAuthCredentials,
+	resetOAuthStorage,
+	saveOAuthCredentials,
+	setOAuthStorage,
+};
 
 // Types for OAuth flow
 export interface OAuthAuthInfo {

packages/coding-agent/src/main.ts

@@ -3,13 +3,15 @@
  */
 
 import { Agent, type Attachment, ProviderTransport, type ThinkingLevel } from "@mariozechner/pi-agent-core";
-import { supportsXhigh } from "@mariozechner/pi-ai";
+import { setOAuthStorage, supportsXhigh } from "@mariozechner/pi-ai";
 import chalk from "chalk";
+import { chmodSync, existsSync, mkdirSync, readFileSync, writeFileSync } from "fs";
+import { dirname } from "path";
 import { type Args, parseArgs, printHelp } from "./cli/args.js";
 import { processFileArguments } from "./cli/file-processor.js";
 import { listModels } from "./cli/list-models.js";
 import { selectSession } from "./cli/session-picker.js";
-import { getModelsPath, VERSION } from "./config.js";
+import { getModelsPath, getOAuthPath, VERSION } from "./config.js";
 import { AgentSession } from "./core/agent-session.js";
 import { discoverAndLoadCustomTools, type LoadedCustomTool } from "./core/custom-tools/index.js";
 import { exportFromFile } from "./core/export-html.js";
@@ -27,6 +29,32 @@ import { initTheme, stopThemeWatcher } from "./modes/interactive/theme/theme.js"
 import { getChangelogPath, getNewEntries, parseChangelog } from "./utils/changelog.js";
 import { ensureTool } from "./utils/tools-manager.js";
 
+/** Configure OAuth storage to use the coding-agent's configurable path */
+function configureOAuthStorage(): void {
+	const oauthPath = getOAuthPath();
+
+	setOAuthStorage({
+		load: () => {
+			if (!existsSync(oauthPath)) {
+				return {};
+			}
+			try {
+				return JSON.parse(readFileSync(oauthPath, "utf-8"));
+			} catch {
+				return {};
+			}
+		},
+		save: (storage) => {
+			const dir = dirname(oauthPath);
+			if (!existsSync(dir)) {
+				mkdirSync(dir, { recursive: true, mode: 0o700 });
+			}
+			writeFileSync(oauthPath, JSON.stringify(storage, null, 2), "utf-8");
+			chmodSync(oauthPath, 0o600);
+		},
+	});
+}
+
 /** Check npm registry for new version (non-blocking) */
 async function checkForNewVersion(currentVersion: string): Promise<string | null> {
 	try {
@@ -142,6 +170,10 @@ async function prepareInitialMessage(parsed: Args): Promise<{
 }
 
 export async function main(args: string[]) {
+	// Configure OAuth storage to use the coding-agent's configurable path
+	// This must happen before any OAuth operations
+	configureOAuthStorage();
+
 	const parsed = parseArgs(args);
 
 	if (parsed.version) {

packages/coding-agent/src/modes/interactive/components/model-selector.ts

@@ -22,6 +22,11 @@ interface ModelItem {
 	model: Model<any>;
 }
 
+interface ScopedModelItem {
+	model: Model<any>;
+	thinkingLevel: string;
+}
+
 /**
  * Component that renders a model selector with search
  */
@@ -37,11 +42,13 @@ export class ModelSelectorComponent extends Container {
 	private onCancelCallback: () => void;
 	private errorMessage: string | null = null;
 	private tui: TUI;
+	private scopedModels: ReadonlyArray<ScopedModelItem>;
 
 	constructor(
 		tui: TUI,
 		currentModel: Model<any> | null,
 		settingsManager: SettingsManager,
+		scopedModels: ReadonlyArray<ScopedModelItem>,
 		onSelect: (model: Model<any>) => void,
 		onCancel: () => void,
 	) {
@@ -50,6 +57,7 @@ export class ModelSelectorComponent extends Container {
 		this.tui = tui;
 		this.currentModel = currentModel;
 		this.settingsManager = settingsManager;
+		this.scopedModels = scopedModels;
 		this.onSelectCallback = onSelect;
 		this.onCancelCallback = onCancel;
 
@@ -57,10 +65,12 @@ export class ModelSelectorComponent extends Container {
 		this.addChild(new DynamicBorder());
 		this.addChild(new Spacer(1));
 
-		// Add hint about API key filtering
-		this.addChild(
-			new Text(theme.fg("warning", "Only showing models with configured API keys (see README for details)"), 0, 0),
-		);
+		// Add hint about model filtering
+		const hintText =
+			scopedModels.length > 0
+				? "Showing models from --models scope"
+				: "Only showing models with configured API keys (see README for details)";
+		this.addChild(new Text(theme.fg("warning", hintText), 0, 0));
 		this.addChild(new Spacer(1));
 
 		// Create search input
@@ -93,24 +103,35 @@ export class ModelSelectorComponent extends Container {
 	}
 
 	private async loadModels(): Promise<void> {
-		// Load available models fresh (includes custom models from models.json)
-		const { models: availableModels, error } = await getAvailableModels();
+		let models: ModelItem[];
 
-		// If there's an error loading models.json, we'll show it via the "no models" path
-		// The error will be displayed to the user
-		if (error) {
-			this.allModels = [];
-			this.filteredModels = [];
-			this.errorMessage = error;
-			return;
+		// Use scoped models if provided via --models flag
+		if (this.scopedModels.length > 0) {
+			models = this.scopedModels.map((scoped) => ({
+				provider: scoped.model.provider,
+				id: scoped.model.id,
+				model: scoped.model,
+			}));
+		} else {
+			// Load available models fresh (includes custom models from models.json)
+			const { models: availableModels, error } = await getAvailableModels();
+
+			// If there's an error loading models.json, we'll show it via the "no models" path
+			// The error will be displayed to the user
+			if (error) {
+				this.allModels = [];
+				this.filteredModels = [];
+				this.errorMessage = error;
+				return;
+			}
+
+			models = availableModels.map((model) => ({
+				provider: model.provider,
+				id: model.id,
+				model,
+			}));
 		}
 
-		const models: ModelItem[] = availableModels.map((model) => ({
-			provider: model.provider,
-			id: model.id,
-			model,
-		}));
-
 		// Sort: current model first, then by provider
 		models.sort((a, b) => {
 			const aIsCurrent = this.currentModel?.id === a.model.id && this.currentModel?.provider === a.provider;

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -1382,6 +1382,7 @@ export class InteractiveMode {
 				this.ui,
 				this.session.model,
 				this.settingsManager,
+				this.session.scopedModels,
 				async (model) => {
 					try {
 						await this.session.setModel(model);