fix(cli): awaited config JSON stdout flush

- Waited for the stdout write callback before the config command exits.
- Covered JSON output larger than the 64 KiB pipe buffer.

Fixes #5309

packages/coding-agent/CHANGELOG.md

@@ -10,6 +10,10 @@
 
 - Updated status event log to prioritize the most recent entries in the display window
 
+### Fixed
+
+- Fixed `omp config list --json` truncating output at 64 KiB when stdout is piped ([#5309](https://github.com/can1357/oh-my-pi/issues/5309))
+
 ### Removed
 
 - Removed the unreliable Bing and Yahoo HTML-scraping web search providers

packages/coding-agent/src/cli/config-cli.ts

@@ -241,7 +241,7 @@ export async function runConfigCommand(cmd: ConfigCommandArgs): Promise<void> {
 
 	switch (cmd.action) {
 		case "list":
-			handleList(cmd.flags);
+			await handleList(cmd.flags);
 			break;
 		case "get":
 			handleGet(cmd.key, cmd.flags);
@@ -261,7 +261,19 @@ export async function runConfigCommand(cmd: ConfigCommandArgs): Promise<void> {
 	}
 }
 
-function handleList(flags: { json?: boolean }): void {
+async function writeStdout(text: string): Promise<void> {
+	const pending = Promise.withResolvers<void>();
+	process.stdout.write(text, error => {
+		if (error) {
+			pending.reject(error);
+			return;
+		}
+		pending.resolve();
+	});
+	await pending.promise;
+}
+
+async function handleList(flags: { json?: boolean }): Promise<void> {
 	const defs = ALL_SETTING_PATHS.map(path => findSettingDef(path)).filter((def): def is CliSettingDef => !!def);
 
 	if (flags.json) {
@@ -273,7 +285,7 @@ function handleList(flags: { json?: boolean }): void {
 				description: def.description,
 			};
 		}
-		console.log(JSON.stringify(result, null, 2));
+		await writeStdout(`${JSON.stringify(result, null, 2)}\n`);
 		return;
 	}
 

packages/coding-agent/test/config-cli.test.ts

@@ -8,6 +8,7 @@ import { getConfigRootDir, setAgentDir, TempDir } from "@oh-my-pi/pi-utils";
 let testAgentDir: TempDir | undefined;
 const originalAgentDir = process.env.PI_CODING_AGENT_DIR;
 const fallbackAgentDir = path.join(getConfigRootDir(), "agent");
+const cliEntry = path.join(import.meta.dir, "..", "src", "cli.ts");
 
 beforeEach(() => {
 	resetSettingsForTest();
@@ -166,4 +167,25 @@ describe("config CLI schema coverage", () => {
 		expect(parsed.type).toBe("enum");
 		expect(parsed.value).toBe("max");
 	});
+	it("fully flushes JSON larger than a pipe buffer", async () => {
+		if (!testAgentDir) throw new Error("Test agent directory was not initialized");
+		const proc = Bun.spawn([process.execPath, cliEntry, "config", "list", "--json"], {
+			stdout: "pipe",
+			stderr: "pipe",
+			env: {
+				...process.env,
+				NO_COLOR: "1",
+				PI_CODING_AGENT_DIR: testAgentDir.path(),
+			},
+		});
+		const stdout = new Response(proc.stdout).text();
+		const stderr = new Response(proc.stderr).text();
+		const [exitCode, output, error] = await Promise.all([proc.exited, stdout, stderr]);
+
+		expect(exitCode).toBe(0);
+		expect(error).toBe("");
+		expect(Buffer.byteLength(output)).toBeGreaterThan(65_536);
+		const parsed: unknown = JSON.parse(output);
+		expect(parsed).toMatchObject({ modelRoles: { type: "record" } });
+	});
 });