fix(coding-agent): reload model config in picker (#7036)

packages/coding-agent/src/core/model-registry.ts

@@ -25,8 +25,8 @@ export class ModelRegistry {
 	}
 
 	/** Reload models.json asynchronously. Await before making synchronous registry reads. */
-	refresh(): Promise<void> {
-		return this.runtime.reloadConfig();
+	async refresh(): Promise<void> {
+		await this.runtime.refresh();
 	}
 
 	getError(): string | undefined {

packages/coding-agent/src/core/model-runtime.ts

@@ -513,14 +513,10 @@ export class ModelRuntime implements Models {
 		await this.refresh({ allowNetwork: this.modelNetworkEnabled });
 	}
 
-	async reloadConfig(): Promise<void> {
+	async refresh(options: ModelsRefreshOptions = {}): Promise<ModelsRefreshResult> {
 		this.config = await ModelConfig.load(this.modelsPath);
 		this.configureRadiusProviders();
 		this.rebuildProviders();
-		await this.refresh({ allowNetwork: this.modelNetworkEnabled });
-	}
-
-	async refresh(options: ModelsRefreshOptions = {}): Promise<ModelsRefreshResult> {
 		const refreshOptions = {
 			...options,
 			allowNetwork: options.allowNetwork ?? this.modelNetworkEnabled,

packages/coding-agent/test/suite/harness.ts

@@ -1,9 +1,9 @@
-import { createInMemoryModelRegistry, getModelRuntime } from "../model-runtime-test-utils.ts";
+import { createInMemoryModelRegistry, createModelRegistry, getModelRuntime } from "../model-runtime-test-utils.ts";
 /**
  * Local test harness for the new coding-agent test suite.
  */
 
-import { existsSync, mkdirSync, rmSync } from "node:fs";
+import { existsSync, mkdirSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import type { AgentMessage, AgentTool } from "@earendil-works/pi-agent-core";
@@ -71,6 +71,7 @@ export interface HarnessOptions {
 	resourceLoader?: ResourceLoader;
 	extensionFactories?: Array<InlineExtension | CreateTestExtensionsResultInput>;
 	withConfiguredAuth?: boolean;
+	modelsJson?: Record<string, unknown>;
 }
 
 export interface Harness {
@@ -115,7 +116,11 @@ export async function createHarness(options: HarnessOptions = {}): Promise<Harne
 	if (withConfiguredAuth) {
 		await authStorage.modify(model.provider, async () => ({ type: "api_key", key: "faux-key" }));
 	}
-	const modelRegistry = await createInMemoryModelRegistry(authStorage);
+	const modelsPath = options.modelsJson === undefined ? undefined : join(tempDir, "models.json");
+	if (modelsPath) writeFileSync(modelsPath, JSON.stringify(options.modelsJson));
+	const modelRegistry = modelsPath
+		? await createModelRegistry(authStorage, modelsPath)
+		: await createInMemoryModelRegistry(authStorage);
 	if (withConfiguredAuth) {
 		modelRegistry.registerProvider(model.provider, {
 			baseUrl: model.baseUrl,

packages/coding-agent/test/suite/regressions/6999-models-json-hot-reload.test.ts

@@ -0,0 +1,68 @@
+import { writeFileSync } from "node:fs";
+import { join } from "node:path";
+import { setKeybindings, type TUI } from "@earendil-works/pi-tui";
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import { KeybindingsManager } from "../../../src/core/keybindings.ts";
+import { ModelSelectorComponent } from "../../../src/modes/interactive/components/model-selector.ts";
+import { initTheme } from "../../../src/modes/interactive/theme/theme.ts";
+import { stripAnsi } from "../../../src/utils/ansi.ts";
+import { createHarness, type Harness } from "../harness.ts";
+
+function createFakeTui(): TUI {
+	return {
+		requestRender: () => {},
+	} as unknown as TUI;
+}
+
+function modelsJson(provider: string, model: string): Record<string, unknown> {
+	return {
+		providers: {
+			[provider]: {
+				baseUrl: "https://example.test/v1",
+				api: "openai-completions",
+				apiKey: "test-key",
+				models: [{ id: model }],
+			},
+		},
+	};
+}
+
+describe("issue #6999 models.json hot reload", () => {
+	let harness: Harness | undefined;
+
+	beforeAll(() => {
+		initTheme("dark");
+	});
+
+	beforeEach(() => {
+		setKeybindings(new KeybindingsManager());
+	});
+
+	afterEach(() => {
+		harness?.cleanup();
+		harness = undefined;
+	});
+
+	it("reloads models.json when opening /model", async () => {
+		harness = await createHarness({ modelsJson: modelsJson("old-provider", "old-model") });
+		expect(harness.session.modelRuntime.getModel("old-provider", "old-model")).toBeDefined();
+
+		writeFileSync(join(harness.tempDir, "models.json"), JSON.stringify(modelsJson("new-provider", "new-model")));
+		const selector = new ModelSelectorComponent(
+			createFakeTui(),
+			harness.getModel(),
+			harness.settingsManager,
+			harness.session.modelRuntime,
+			[],
+			() => {},
+			() => {},
+		);
+
+		await vi.waitFor(() => {
+			const rendered = stripAnsi(selector.render(120).join("\n"));
+			expect(rendered).toContain("new-model [new-provider]");
+			expect(rendered).toContain("Model catalogs refreshed.");
+		});
+		expect(harness.session.modelRuntime.getModel("old-provider", "old-model")).toBeUndefined();
+	});
+});