diff --git a/bin/qc.js b/bin/qc.js
index 3f9e1dd5..8bb0dac0 100755
--- a/bin/qc.js
+++ b/bin/qc.js
@@ -1,16 +1,17 @@
 #!/usr/bin/env node
 // qc: qrypt.chat in the terminal. `qc` opens the chat client; `qc --help` lists the rest.
 import { readFileSync } from 'node:fs';
-import { errorLine, main } from '../src/cli/commands.js';
+import { errorLine, exitWhenFlushed, main } from '../src/cli/commands.js';
 
 const pkg = JSON.parse(readFileSync(new URL('../package.json', import.meta.url), 'utf8'));
 
 // main resolves when the command is done (the TUI quit, stdin closed under
-// mcp); exit then, or the SSE socket and timers would hold the process open.
+// mcp); exit then, or the SSE socket and timers would hold the process open,
+// but only once stdout has drained (see exit.js).
 main(process.argv.slice(2), { version: pkg.version }).then(
-	() => process.exit(0),
+	() => exitWhenFlushed(0),
 	(err) => {
 		process.stderr.write(`${errorLine(err)}\n`);
-		process.exit(1);
+		exitWhenFlushed(1);
 	},
 );
diff --git a/packages/qryptchat/bin/qc.js b/packages/qryptchat/bin/qc.js
index f095126a..a290c2d7 100644
--- a/packages/qryptchat/bin/qc.js
+++ b/packages/qryptchat/bin/qc.js
@@ -1,14 +1,14 @@
 #!/usr/bin/env node
 // qc: qrypt.chat in the terminal. `qc` opens the chat client; `qc --help` lists the rest.
 import { readFileSync } from 'node:fs';
-import { errorLine, main } from '../dist/commands.js';
+import { errorLine, exitWhenFlushed, main } from '../dist/commands.js';
 
 const pkg = JSON.parse(readFileSync(new URL('../package.json', import.meta.url), 'utf8'));
 
 main(process.argv.slice(2), { version: pkg.version }).then(
-	() => process.exit(0),
+	() => exitWhenFlushed(0),
 	(err) => {
 		process.stderr.write(`${errorLine(err)}\n`);
-		process.exit(1);
+		exitWhenFlushed(1);
 	},
 );
diff --git a/packages/qryptchat/package.json b/packages/qryptchat/package.json
index 583a501e..bb1453ac 100644
--- a/packages/qryptchat/package.json
+++ b/packages/qryptchat/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@profullstack/qryptchat",
-  "version": "0.6.3",
+  "version": "0.6.4",
   "description": "qc: qrypt.chat in your terminal. A full-screen end-to-end encrypted chat client (ML-KEM-1024), plus a scriptable CLI and an MCP server.",
   "type": "module",
   "bin": {
diff --git a/src/cli/commands.js b/src/cli/commands.js
index 178b9af8..55adb5e8 100644
--- a/src/cli/commands.js
+++ b/src/cli/commands.js
@@ -8,6 +8,7 @@ import { login } from './login.js';
 import { joinAsAgent } from './agent.js';
 import { em, fail, info, mark, ok, warn, who } from './style.js';
 import { notify } from './notify.js';
+export { exitWhenFlushed } from './exit.js';
 
 /** An error as qc prints it: the error icon and the message. */
 export const errorLine = (err) => `qc: ${fail(err?.message ?? String(err))}`;
diff --git a/src/cli/exit.js b/src/cli/exit.js
new file mode 100644
index 00000000..6d4ac522
--- /dev/null
+++ b/src/cli/exit.js
@@ -0,0 +1,10 @@
+// process.exit() does not wait for stdout. Into a pipe (qc read --json | jq, a
+// script's subprocess) the write is asynchronous, so anything past the 64 KB
+// pipe buffer was dropped and the reader got truncated JSON. Exit once both
+// streams have finished; the timer only guards a reader that never reads.
+// end(), not write('', cb): under Bun an empty write calls back before the
+// earlier data has drained.
+export function exitWhenFlushed(code, { timeoutMs = 30_000 } = {}) {
+	setTimeout(() => process.exit(code), timeoutMs);
+	process.stdout.end(() => process.stderr.end(() => process.exit(code)));
+}
diff --git a/tests/cli/exit.test.js b/tests/cli/exit.test.js
new file mode 100644
index 00000000..454726b8
--- /dev/null
+++ b/tests/cli/exit.test.js
@@ -0,0 +1,35 @@
+import { spawnSync } from 'node:child_process';
+import { resolve } from 'node:path';
+import { pathToFileURL } from 'node:url';
+import { describe, expect, it } from 'vitest';
+
+// vitest runs from the repo root; import.meta.url is http:// under jsdom.
+const exitJs = pathToFileURL(resolve('src/cli/exit.js')).href;
+const SIZE = 1024 * 1024;
+
+// Run a child that writes SIZE bytes to a piped stdout, then exits the given way.
+// `node` is Bun under `bun --bun vitest`, so this covers both runtimes between
+// a local `node` run and CI.
+function run(exit) {
+	const script = `import { exitWhenFlushed } from ${JSON.stringify(exitJs)};
+process.stdout.write('x'.repeat(${SIZE}));
+${exit}`;
+	const r = spawnSync('node', ['--input-type=module', '-e', script], { maxBuffer: SIZE * 2 });
+	return r;
+}
+
+describe('exitWhenFlushed', () => {
+	it('delivers all of a large piped stdout before exiting', () => {
+		const r = run('exitWhenFlushed(0);');
+		expect(r.status).toBe(0);
+		expect(r.stdout.length).toBe(SIZE);
+	});
+
+	it('keeps the exit code', () => {
+		expect(run('exitWhenFlushed(3);').status).toBe(3);
+	});
+
+	it('is needed: a bare process.exit truncates at the pipe buffer', () => {
+		expect(run('process.exit(0);').stdout.length).toBeLessThan(SIZE);
+	});
+});