Add startup session name flag

closes #5153

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

@@ -157,6 +157,36 @@ describe("parseArgs", () => {
 		});
 	});
 
+	describe("--name flag", () => {
+		test("parses --name flag with value", () => {
+			const result = parseArgs(["--name", "my-session"]);
+			expect(result.name).toBe("my-session");
+		});
+
+		test("parses -n shorthand", () => {
+			const result = parseArgs(["-n", "quick-session"]);
+			expect(result.name).toBe("quick-session");
+		});
+
+		test("preserves empty values for main validation", () => {
+			const result = parseArgs(["--name", ""]);
+			expect(result.name).toBe("");
+		});
+
+		test("reports missing value", () => {
+			const result = parseArgs(["--name"]);
+			expect(result.diagnostics).toEqual([{ type: "error", message: "--name requires a value" }]);
+		});
+
+		test("works alongside other flags", () => {
+			const result = parseArgs(["--name", "named-run", "--print", "--model", "gpt-4o", "hello"]);
+			expect(result.name).toBe("named-run");
+			expect(result.print).toBe(true);
+			expect(result.model).toBe("gpt-4o");
+			expect(result.messages).toEqual(["hello"]);
+		});
+	});
+
 	describe("--no-session flag", () => {
 		test("parses --no-session flag", () => {
 			const result = parseArgs(["--no-session"]);

packages/coding-agent/test/startup-session-name.test.ts

@@ -0,0 +1,135 @@
+import { spawn } from "node:child_process";
+import { mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join, resolve } from "node:path";
+import { afterEach, describe, expect, it } from "vitest";
+import { ENV_AGENT_DIR } from "../src/config.ts";
+
+const cliPath = resolve(__dirname, "../src/cli.ts");
+const tempDirs: string[] = [];
+
+afterEach(() => {
+	for (const dir of tempDirs.splice(0)) {
+		rmSync(dir, { recursive: true, force: true });
+	}
+});
+
+function createTempDir(): string {
+	const dir = mkdtempSync(join(tmpdir(), "pi-startup-session-name-"));
+	tempDirs.push(dir);
+	return dir;
+}
+
+interface CliDirs {
+	agentDir: string;
+	projectDir: string;
+	sessionFile: string;
+}
+
+interface CliResult {
+	code: number | null;
+	signal: NodeJS.Signals | null;
+	stderr: string;
+}
+
+function createSessionFile(projectDir: string, sessionFile: string): void {
+	const timestamp = new Date().toISOString();
+	writeFileSync(
+		sessionFile,
+		`${JSON.stringify({ type: "session", version: 3, id: "existing-session", timestamp, cwd: projectDir })}\n${JSON.stringify(
+			{
+				type: "message",
+				id: "assistant-1",
+				parentId: null,
+				timestamp,
+				message: {
+					role: "assistant",
+					content: [{ type: "text", text: "hello" }],
+					provider: "anthropic",
+					model: "claude-sonnet-4-5",
+					timestamp: Date.now(),
+				},
+			},
+		)}\n`,
+	);
+}
+
+function readSessionInfoNames(sessionFile: string): string[] {
+	return readFileSync(sessionFile, "utf8")
+		.trim()
+		.split("\n")
+		.map((line) => JSON.parse(line) as { type?: string; name?: string })
+		.filter((entry) => entry.type === "session_info")
+		.map((entry) => entry.name ?? "");
+}
+
+async function runCli(args: string[], dirs: CliDirs): Promise<CliResult> {
+	let stderr = "";
+	const child = spawn(process.execPath, [cliPath, ...args], {
+		cwd: dirs.projectDir,
+		env: {
+			...process.env,
+			[ENV_AGENT_DIR]: dirs.agentDir,
+			PI_OFFLINE: "1",
+			TSX_TSCONFIG_PATH: resolve(__dirname, "../../../tsconfig.json"),
+		},
+		stdio: ["ignore", "ignore", "pipe"],
+	});
+	child.stderr.on("data", (chunk) => {
+		stderr += chunk.toString();
+	});
+
+	return new Promise((resolvePromise, reject) => {
+		const timeout = setTimeout(() => {
+			child.kill("SIGKILL");
+		}, 10_000);
+		child.on("error", (error) => {
+			clearTimeout(timeout);
+			reject(error);
+		});
+		child.on("close", (code, signal) => {
+			clearTimeout(timeout);
+			resolvePromise({ code, signal, stderr });
+		});
+	});
+}
+
+function setup(): CliDirs {
+	const tempRoot = createTempDir();
+	const dirs = {
+		agentDir: join(tempRoot, "agent"),
+		projectDir: join(tempRoot, "project"),
+		sessionFile: join(tempRoot, "session.jsonl"),
+	};
+	mkdirSync(dirs.agentDir, { recursive: true });
+	mkdirSync(dirs.projectDir, { recursive: true });
+	createSessionFile(dirs.projectDir, dirs.sessionFile);
+	return dirs;
+}
+
+describe("startup session name", () => {
+	it("sets --name on the selected session before runtime model validation", async () => {
+		const dirs = setup();
+		const result = await runCli(
+			["--session", dirs.sessionFile, "--name", "  CLI Named Session  ", "--model", "missing-model", "-p", "hi"],
+			dirs,
+		);
+
+		expect(result.code).toBe(1);
+		expect(result.signal).toBeNull();
+		expect(readSessionInfoNames(dirs.sessionFile)).toEqual(["CLI Named Session"]);
+	});
+
+	it("rejects empty --name values without appending session metadata", async () => {
+		const dirs = setup();
+		const result = await runCli(
+			["--session", dirs.sessionFile, "--name", "   ", "--model", "missing-model", "-p", "hi"],
+			dirs,
+		);
+
+		expect(result.code).toBe(1);
+		expect(result.signal).toBeNull();
+		expect(result.stderr).toContain("--name requires a non-empty value");
+		expect(readSessionInfoNames(dirs.sessionFile)).toEqual([]);
+	});
+});