feat(coding-agent): add exclude tools option closes #5109

packages/coding-agent/test/args.test.ts

@@ -308,6 +308,16 @@ describe("parseArgs", () => {
 			expect(result.tools).toEqual(["read", "bash"]);
 		});
 
+		test("parses --exclude-tools flag", () => {
+			const result = parseArgs(["--exclude-tools", "read,bash"]);
+			expect(result.excludeTools).toEqual(["read", "bash"]);
+		});
+
+		test("parses -xt shorthand", () => {
+			const result = parseArgs(["-xt", "read,bash"]);
+			expect(result.excludeTools).toEqual(["read", "bash"]);
+		});
+
 		test("parses --no-tools with explicit --tools flags", () => {
 			const result = parseArgs(["--no-tools", "--tools", "read,bash"]);
 			expect(result.noTools).toBe(true);

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

@@ -60,6 +60,9 @@ export interface HarnessOptions {
 	settings?: Partial<Settings>;
 	systemPrompt?: string;
 	tools?: AgentTool[];
+	initialActiveToolNames?: string[];
+	allowedToolNames?: string[];
+	excludedToolNames?: string[];
 	resourceLoader?: ResourceLoader;
 	extensionFactories?: Array<ExtensionFactory | CreateTestExtensionsResultInput>;
 	withConfiguredAuth?: boolean;
@@ -173,6 +176,9 @@ export async function createHarness(options: HarnessOptions = {}): Promise<Harne
 		modelRegistry,
 		resourceLoader,
 		baseToolsOverride: toolMap,
+		initialActiveToolNames: options.initialActiveToolNames,
+		allowedToolNames: options.allowedToolNames,
+		excludedToolNames: options.excludedToolNames,
 		extensionRunnerRef,
 	});
 

packages/coding-agent/test/suite/regressions/5109-exclude-tools.test.ts

@@ -0,0 +1,81 @@
+import { Type } from "typebox";
+import { describe, expect, it } from "vitest";
+import type { ExtensionFactory } from "../../../src/index.ts";
+import { createHarness } from "../harness.ts";
+
+function toolNames(tools: Array<{ name: string }>): string[] {
+	return tools.map((tool) => tool.name).sort();
+}
+
+describe("regression #5109: exclude tools", () => {
+	const extensionFactories: ExtensionFactory[] = [
+		(pi) => {
+			pi.on("session_start", () => {
+				pi.registerTool({
+					name: "ask_question",
+					label: "Ask Question",
+					description: "Ask a question",
+					promptSnippet: "Ask a question",
+					parameters: Type.Object({}),
+					execute: async () => ({
+						content: [{ type: "text", text: "ok" }],
+						details: {},
+					}),
+				});
+				pi.registerTool({
+					name: "dynamic_tool",
+					label: "Dynamic Tool",
+					description: "Dynamic test tool",
+					promptSnippet: "Run dynamic test behavior",
+					parameters: Type.Object({}),
+					execute: async () => ({
+						content: [{ type: "text", text: "ok" }],
+						details: {},
+					}),
+				});
+			});
+		},
+	];
+
+	it("filters built-in and extension tools from available and active tools", async () => {
+		const harness = await createHarness({
+			excludedToolNames: ["read", "ask_question"],
+			extensionFactories,
+		});
+		try {
+			await harness.session.bindExtensions({});
+
+			const allToolNames = toolNames(harness.session.getAllTools());
+			expect(allToolNames).not.toContain("read");
+			expect(allToolNames).not.toContain("ask_question");
+			expect(allToolNames).toContain("bash");
+			expect(allToolNames).toContain("dynamic_tool");
+			expect(harness.session.getActiveToolNames().sort()).toEqual(["bash", "dynamic_tool", "edit", "write"]);
+			expect(harness.session.systemPrompt).not.toContain("- read:");
+			expect(harness.session.systemPrompt).not.toContain("ask_question");
+			expect(harness.session.systemPrompt).toContain("- dynamic_tool: Run dynamic test behavior");
+		} finally {
+			harness.cleanup();
+		}
+	});
+
+	it("lets excluded tools override the allowlist", async () => {
+		const harness = await createHarness({
+			allowedToolNames: ["read", "bash", "ask_question"],
+			excludedToolNames: ["read", "ask_question"],
+			initialActiveToolNames: ["read", "bash", "ask_question"],
+			extensionFactories,
+		});
+		try {
+			await harness.session.bindExtensions({});
+
+			expect(toolNames(harness.session.getAllTools())).toEqual(["bash"]);
+			expect(harness.session.getActiveToolNames()).toEqual(["bash"]);
+			expect(harness.session.systemPrompt).toContain("- bash:");
+			expect(harness.session.systemPrompt).not.toContain("- read:");
+			expect(harness.session.systemPrompt).not.toContain("ask_question");
+		} finally {
+			harness.cleanup();
+		}
+	});
+});