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feat(dev): supervise every runtime in headless mode #2138

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45a092e
feat(dev): supervise every runtime in headless mode
tejaskash Aug 28, 2026
ba8cddf
refactor(dev): drop the dead await on eager start results
tejaskash Aug 28, 2026
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97 changes: 80 additions & 17 deletions src/handlers/project/dev/index.test.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -4,6 +4,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
InputValidationError,
ResourceNotFoundError,
SilentCLIError,
UserCancellationError,
} from "../../../errors";
import type { HttpRequestHandler, PortChecker } from "../../../io";
Expand DownExpand Up@@ -45,6 +46,22 @@ function captureRunner(events: DevEvent[] = []) {
return { runner, inputs };
}

/** A runner that emits `events` then stays alive until aborted, like a real dev server. */
function stayingRunner(events: DevEvent[] = []) {
const inputs: DevServerInput[] = [];
const runner: DevRunner = {
run: async function* (input) {
inputs.push(input);
yield* events;
if (input.signal.aborted) return;
await new Promise<void>((resolve) =>
input.signal.addEventListener("abort", () => resolve(), { once: true }),
);
},
};
return { runner, inputs };
}

function fakeCollector() {
const starts: Parameters<DevProjectHandlerConfig["startTraceCollector"]>[0][] = [];
const state = { closed: 0 };
Expand DownExpand Up@@ -120,6 +137,9 @@ function harness(options: HarnessOptions = {}) {
resolve: async () =>
options.reloadedRuntimes ? project(...options.reloadedRuntimes) : undefined,
},
waitReady: async () => {
await Bun.sleep(5);
},
});
const ctx = ValueContext.EmptyContext()
.withValue(ProjectKey, options.project ?? project(runtime()))
Expand DownExpand Up@@ -167,16 +187,10 @@ async function inspectorStatus(subject: ReturnType<typeof harness>): Promise<{ n
describe("project dev selection and dispatch", () => {
test.each([
[project(), {}, "This project has no runtimes", InputValidationError],
[
project(runtime("orders")),
{},
"--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders",
InputValidationError,
],
[
project(runtime("orders"), runtime("support", "Container")),
{},
"--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders, support",
{ port: 4567 },
"--port applies to a single runtime. Use --agent to select one.",
InputValidationError,
],
[
Expand DownExpand Up@@ -237,6 +251,64 @@ describe("project dev selection and dispatch", () => {
});
});

describe("project dev headless multi-agent", () => {
const twoRuntimes = () => project(runtime("orders"), runtime("support", "Container"));

/** Start a headless multi-agent run and give its agents time to reach "running". */
async function supervised(subject: ReturnType<typeof harness>) {
const pending = subject.run();
pending.catch(() => undefined);
await Bun.sleep(30);
return { pending };
}

test("supervises every runtime with attributed output and per-runtime env", async () => {
const codeZip = stayingRunner([{ type: "stdout", line: "orders says hi" }]);
const container = stayingRunner();
const subject = harness({ project: twoRuntimes(), codeZip, container });
const { pending } = await supervised(subject);

expect(codeZip.inputs).toHaveLength(1);
expect(container.inputs).toHaveLength(1);
expect(codeZip.inputs[0]!.env).toMatchObject({
OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:43180",
OTEL_SERVICE_NAME: "orders",
});
expect(container.inputs[0]!.env).toMatchObject({
OTEL_EXPORTER_OTLP_ENDPOINT: "http://host.docker.internal:43180",
OTEL_SERVICE_NAME: "support",
});
expect(subject.io.stdout()).toContain("[orders] orders says hi");
expect(subject.io.stderr()).toContain("Agent 'orders' is running on port");

process.emit("SIGINT", "SIGINT");
await expect(pending).rejects.toMatchObject({ exitCode: 130 });
expect(subject.collector.state.closed).toBe(1);
});

test("one agent failing to start leaves the others running", async () => {
const subject = harness({
project: twoRuntimes(),
codeZip: captureRunner([{ type: "status", message: "dying" }]),
container: stayingRunner(),
});
const { pending } = await supervised(subject);

expect(subject.io.stderr()).toContain("[orders] Agent 'orders' failed to start");
expect(subject.io.stderr()).toContain("Agent 'support' is running on port");

process.emit("SIGINT", "SIGINT");
await pending.catch(() => undefined);
});

test("exits non-zero when every agent fails to start", async () => {
const subject = harness({ project: twoRuntimes() });

await expect(subject.run()).rejects.toBeInstanceOf(SilentCLIError);
expect(subject.collector.state.closed).toBe(1);
});
});

describe("project dev trace collection", () => {
test("starts the collector, announces it, and points a CodeZip agent at loopback", async () => {
const subject = harness();
Expand DownExpand Up@@ -396,15 +468,6 @@ describe("project dev Inspector UI mode", () => {
"Port 9999 is already in use",
);
});

test("--port with several runtimes is rejected", async () => {
const subject = harness({
project: project(runtime("orders"), runtime("support", "Container")),
});
await expect(subject.run({ mode: "browser", port: 4567 })).rejects.toThrow(
"--port applies to a single runtime",
);
});
});

test("project dev renders attributed human and NDJSON output", async () => {
Expand Down
25 changes: 17 additions & 8 deletions src/handlers/project/dev/index.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -10,6 +10,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
InputValidationError,
ResourceNotFoundError,
SilentCLIError,
UserCancellationError,
} from "../../../errors";
import type { AppIO, BrowserOpener, FileWatcher, PortChecker, startHttpServer } from "../../../io";
Expand DownExpand Up@@ -102,7 +103,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
flag("traces", "disable local OTEL trace collection", z.boolean().default(true)),
flag(
"mode",
"how to run: browser (Agent Inspector web UI), headless (one agent in the terminal), or tui",
"how to run: browser (Agent Inspector web UI), headless (agents stream to the terminal), or tui",
z.enum(["browser", "headless", "tui"]).default("browser"),
),
flag(
Expand DownExpand Up@@ -132,12 +133,6 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
);
}
const runtimes = selectRuntimes(project, flags.agent);
if (flags.mode === "headless" && !flags.agent) {
const available = runtimes.map((runtime) => runtime.name).join(", ");
throw new InputValidationError(
`--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: ${available}.`,
);
}
if (runtimes.length > 1 && flags.port !== undefined) {
throw new InputValidationError(
"--port applies to a single runtime. Use --agent to select one.",
Expand DownExpand Up@@ -194,7 +189,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
return { ...env, ...otel };
};

if (flags.mode === "headless") {
if (flags.mode === "headless" && flags.agent) {
await runWithoutUi(
config,
runtimes[0]!,
Expand DownExpand Up@@ -227,6 +222,20 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
signal: controller.signal,
});

if (flags.mode === "headless") {
void Promise.allSettled(runtimes.map((runtime) => supervisor.start(runtime.name)));
for await (const { agentName, event } of supervisor.events()) {

@aidandaly24aidandaly24Aug 28, 2026

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I think normal Ctrl-C gets reported as a crash in this supervised headless path. The production process runner rejects with the child signal's UserCancellationError, so the supervisor emits Agent 'orders' crashed: Operation cancelled by user before the command exits 130. Could the supervisor treat an error from an already-aborted child signal as a normal stop? A test where the runner throws input.signal.reason on abort would cover the production behavior better than stayingRunner, which returns cleanly.

renderAgentEvent(config.io, event, agentName, json);
const phases = supervisor.snapshot();
if (phases.every(({ phase }) => phase !== "starting" && phase !== "running")) {
if (phases.some(({ phase }) => phase === "failed")) throw new SilentCLIError();
break;
}
}
controller.signal.throwIfAborted();
return;
}

const uiPort = (
await findFreePort(UI_DEFAULT_PORT, flags["ui-port"], config.checkPort, controller.signal)
).port;
Expand Down
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
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addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
feat(dev): supervise every runtime in headless mode by tejaskash · Pull Request #2138 · aws/agentcore-cli · GitHub
Skip to content
feat(dev): supervise every runtime in headless mode#2138

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−25

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feat(dev): supervise every runtime in headless mode
#2138
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45a092e

feat(dev): supervise every runtime in headless mode


tejaskash Aug 28, 2026
ba8cddf

refactor(dev): drop the dead await on eager start results


tejaskash Aug 28, 2026

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97 changes: 80 additions & 17 deletions
src/handlers/project/dev/index.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -4,6 +4,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { HttpRequestHandler, PortChecker } from "../../../io";
Expand DownExpand Up@@ -45,6 +46,22 @@ function captureRunner(events: DevEvent[] = []) {
 return { runner, inputs };
}

/** A runner that emits `events` then stays alive until aborted, like a real dev server. */
function stayingRunner(events: DevEvent[] = []) {
 const inputs: DevServerInput[] = [];
 const runner: DevRunner = {
 run: async function* (input) {
 inputs.push(input);
 yield* events;
 if (input.signal.aborted) return;
 await new Promise<void>((resolve) =>
 input.signal.addEventListener("abort", () => resolve(), { once: true }),
 );
 },
 };
 return { runner, inputs };
}

function fakeCollector() {
 const starts: Parameters<DevProjectHandlerConfig["startTraceCollector"]>[0][] = [];
 const state = { closed: 0 };
Expand DownExpand Up@@ -120,6 +137,9 @@ function harness(options: HarnessOptions = {}) {
 resolve: async () =>
 options.reloadedRuntimes ? project(...options.reloadedRuntimes) : undefined,
 },
 waitReady: async () => {
 await Bun.sleep(5);
 },
 });
 const ctx = ValueContext.EmptyContext()
 .withValue(ProjectKey, options.project ?? project(runtime()))
Expand DownExpand Up@@ -167,16 +187,10 @@ async function inspectorStatus(subject: ReturnType<typeof harness>): Promise<{ n
describe("project dev selection and dispatch", () => {
 test.each([
 [project(), {}, "This project has no runtimes", InputValidationError],
 [
 project(runtime("orders")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders",
 InputValidationError,
 ],
 [
 project(runtime("orders"), runtime("support", "Container")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders, support",
 { port: 4567 },
 "--port applies to a single runtime. Use --agent to select one.",
 InputValidationError,
 ],
 [
Expand DownExpand Up@@ -237,6 +251,64 @@ describe("project dev selection and dispatch", () => {
 });
});

describe("project dev headless multi-agent", () => {
 const twoRuntimes = () => project(runtime("orders"), runtime("support", "Container"));

 /** Start a headless multi-agent run and give its agents time to reach "running". */
 async function supervised(subject: ReturnType<typeof harness>) {
 const pending = subject.run();
 pending.catch(() => undefined);
 await Bun.sleep(30);
 return { pending };
 }

 test("supervises every runtime with attributed output and per-runtime env", async () => {
 const codeZip = stayingRunner([{ type: "stdout", line: "orders says hi" }]);
 const container = stayingRunner();
 const subject = harness({ project: twoRuntimes(), codeZip, container });
 const { pending } = await supervised(subject);

 expect(codeZip.inputs).toHaveLength(1);
 expect(container.inputs).toHaveLength(1);
 expect(codeZip.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:43180",
 OTEL_SERVICE_NAME: "orders",
 });
 expect(container.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://host.docker.internal:43180",
 OTEL_SERVICE_NAME: "support",
 });
 expect(subject.io.stdout()).toContain("[orders] orders says hi");
 expect(subject.io.stderr()).toContain("Agent 'orders' is running on port");

 process.emit("SIGINT", "SIGINT");
 await expect(pending).rejects.toMatchObject({ exitCode: 130 });
 expect(subject.collector.state.closed).toBe(1);
 });

 test("one agent failing to start leaves the others running", async () => {
 const subject = harness({
 project: twoRuntimes(),
 codeZip: captureRunner([{ type: "status", message: "dying" }]),
 container: stayingRunner(),
 });
 const { pending } = await supervised(subject);

 expect(subject.io.stderr()).toContain("[orders] Agent 'orders' failed to start");
 expect(subject.io.stderr()).toContain("Agent 'support' is running on port");

 process.emit("SIGINT", "SIGINT");
 await pending.catch(() => undefined);
 });

 test("exits non-zero when every agent fails to start", async () => {
 const subject = harness({ project: twoRuntimes() });

 await expect(subject.run()).rejects.toBeInstanceOf(SilentCLIError);
 expect(subject.collector.state.closed).toBe(1);
 });
});

describe("project dev trace collection", () => {
 test("starts the collector, announces it, and points a CodeZip agent at loopback", async () => {
 const subject = harness();
Expand DownExpand Up@@ -396,15 +468,6 @@ describe("project dev Inspector UI mode", () => {
 "Port 9999 is already in use",
 );
 });

 test("--port with several runtimes is rejected", async () => {
 const subject = harness({
 project: project(runtime("orders"), runtime("support", "Container")),
 });
 await expect(subject.run({ mode: "browser", port: 4567 })).rejects.toThrow(
 "--port applies to a single runtime",
 );
 });
});

test("project dev renders attributed human and NDJSON output", async () => {
Expand Down

25 changes: 17 additions & 8 deletions
src/handlers/project/dev/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10,6 +10,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { AppIO, BrowserOpener, FileWatcher, PortChecker, startHttpServer } from "../../../io";
Expand DownExpand Up@@ -102,7 +103,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 flag("traces", "disable local OTEL trace collection", z.boolean().default(true)),
 flag(
 "mode",
 "how to run: browser (Agent Inspector web UI), headless (one agent in the terminal), or tui",
 "how to run: browser (Agent Inspector web UI), headless (agents stream to the terminal), or tui",
 z.enum(["browser", "headless", "tui"]).default("browser"),
 ),
 flag(
Expand DownExpand Up@@ -132,12 +133,6 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 );
 }
 const runtimes = selectRuntimes(project, flags.agent);
 if (flags.mode === "headless" && !flags.agent) {
 const available = runtimes.map((runtime) => runtime.name).join(", ");
 throw new InputValidationError(
 `--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: ${available}.`,
 );
 }
 if (runtimes.length > 1 && flags.port !== undefined) {
 throw new InputValidationError(
 "--port applies to a single runtime. Use --agent to select one.",
Expand DownExpand Up@@ -194,7 +189,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 return { ...env, ...otel };
 };

 if (flags.mode === "headless") {
 if (flags.mode === "headless" && flags.agent) {
 await runWithoutUi(
 config,
 runtimes[0]!,
Expand DownExpand Up@@ -227,6 +222,20 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 signal: controller.signal,
 });

 if (flags.mode === "headless") {
 void Promise.allSettled(runtimes.map((runtime) => supervisor.start(runtime.name)));
 for await (const { agentName, event } of supervisor.events()) {
@aidandaly24aidandaly24Aug 28, 2026

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I think normal Ctrl-C gets reported as a crash in this supervised headless path. The production process runner rejects with the child signal's UserCancellationError, so the supervisor emits Agent 'orders' crashed: Operation cancelled by user before the command exits 130. Could the supervisor treat an error from an already-aborted child signal as a normal stop? A test where the runner throws input.signal.reason on abort would cover the production behavior better than stayingRunner, which returns cleanly.
 renderAgentEvent(config.io, event, agentName, json);
 const phases = supervisor.snapshot();
 if (phases.every(({ phase }) => phase !== "starting" && phase !== "running")) {
 if (phases.some(({ phase }) => phase === "failed")) throw new SilentCLIError();
 break;
 }
 }
 controller.signal.throwIfAborted();
 return;
 }

 const uiPort = (
 await findFreePort(UI_DEFAULT_PORT, flags["ui-port"], config.checkPort, controller.signal)
 ).port;
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(dev): supervise every runtime in headless mode by tejaskash · Pull Request #2138 · aws/agentcore-cli · GitHub
Skip to content
feat(dev): supervise every runtime in headless mode#2138

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 Open

tejaskash
wants to merge
2
commits into

base:refactor
Choose a base branch

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+97

−25

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feat(dev): supervise every runtime in headless mode
#2138
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45a092e

feat(dev): supervise every runtime in headless mode


tejaskash Aug 28, 2026
ba8cddf

refactor(dev): drop the dead await on eager start results


tejaskash Aug 28, 2026

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97 changes: 80 additions & 17 deletions
src/handlers/project/dev/index.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -4,6 +4,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { HttpRequestHandler, PortChecker } from "../../../io";
Expand DownExpand Up@@ -45,6 +46,22 @@ function captureRunner(events: DevEvent[] = []) {
 return { runner, inputs };
}

/** A runner that emits `events` then stays alive until aborted, like a real dev server. */
function stayingRunner(events: DevEvent[] = []) {
 const inputs: DevServerInput[] = [];
 const runner: DevRunner = {
 run: async function* (input) {
 inputs.push(input);
 yield* events;
 if (input.signal.aborted) return;
 await new Promise<void>((resolve) =>
 input.signal.addEventListener("abort", () => resolve(), { once: true }),
 );
 },
 };
 return { runner, inputs };
}

function fakeCollector() {
 const starts: Parameters<DevProjectHandlerConfig["startTraceCollector"]>[0][] = [];
 const state = { closed: 0 };
Expand DownExpand Up@@ -120,6 +137,9 @@ function harness(options: HarnessOptions = {}) {
 resolve: async () =>
 options.reloadedRuntimes ? project(...options.reloadedRuntimes) : undefined,
 },
 waitReady: async () => {
 await Bun.sleep(5);
 },
 });
 const ctx = ValueContext.EmptyContext()
 .withValue(ProjectKey, options.project ?? project(runtime()))
Expand DownExpand Up@@ -167,16 +187,10 @@ async function inspectorStatus(subject: ReturnType<typeof harness>): Promise<{ n
describe("project dev selection and dispatch", () => {
 test.each([
 [project(), {}, "This project has no runtimes", InputValidationError],
 [
 project(runtime("orders")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders",
 InputValidationError,
 ],
 [
 project(runtime("orders"), runtime("support", "Container")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders, support",
 { port: 4567 },
 "--port applies to a single runtime. Use --agent to select one.",
 InputValidationError,
 ],
 [
Expand DownExpand Up@@ -237,6 +251,64 @@ describe("project dev selection and dispatch", () => {
 });
});

describe("project dev headless multi-agent", () => {
 const twoRuntimes = () => project(runtime("orders"), runtime("support", "Container"));

 /** Start a headless multi-agent run and give its agents time to reach "running". */
 async function supervised(subject: ReturnType<typeof harness>) {
 const pending = subject.run();
 pending.catch(() => undefined);
 await Bun.sleep(30);
 return { pending };
 }

 test("supervises every runtime with attributed output and per-runtime env", async () => {
 const codeZip = stayingRunner([{ type: "stdout", line: "orders says hi" }]);
 const container = stayingRunner();
 const subject = harness({ project: twoRuntimes(), codeZip, container });
 const { pending } = await supervised(subject);

 expect(codeZip.inputs).toHaveLength(1);
 expect(container.inputs).toHaveLength(1);
 expect(codeZip.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:43180",
 OTEL_SERVICE_NAME: "orders",
 });
 expect(container.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://host.docker.internal:43180",
 OTEL_SERVICE_NAME: "support",
 });
 expect(subject.io.stdout()).toContain("[orders] orders says hi");
 expect(subject.io.stderr()).toContain("Agent 'orders' is running on port");

 process.emit("SIGINT", "SIGINT");
 await expect(pending).rejects.toMatchObject({ exitCode: 130 });
 expect(subject.collector.state.closed).toBe(1);
 });

 test("one agent failing to start leaves the others running", async () => {
 const subject = harness({
 project: twoRuntimes(),
 codeZip: captureRunner([{ type: "status", message: "dying" }]),
 container: stayingRunner(),
 });
 const { pending } = await supervised(subject);

 expect(subject.io.stderr()).toContain("[orders] Agent 'orders' failed to start");
 expect(subject.io.stderr()).toContain("Agent 'support' is running on port");

 process.emit("SIGINT", "SIGINT");
 await pending.catch(() => undefined);
 });

 test("exits non-zero when every agent fails to start", async () => {
 const subject = harness({ project: twoRuntimes() });

 await expect(subject.run()).rejects.toBeInstanceOf(SilentCLIError);
 expect(subject.collector.state.closed).toBe(1);
 });
});

describe("project dev trace collection", () => {
 test("starts the collector, announces it, and points a CodeZip agent at loopback", async () => {
 const subject = harness();
Expand DownExpand Up@@ -396,15 +468,6 @@ describe("project dev Inspector UI mode", () => {
 "Port 9999 is already in use",
 );
 });

 test("--port with several runtimes is rejected", async () => {
 const subject = harness({
 project: project(runtime("orders"), runtime("support", "Container")),
 });
 await expect(subject.run({ mode: "browser", port: 4567 })).rejects.toThrow(
 "--port applies to a single runtime",
 );
 });
});

test("project dev renders attributed human and NDJSON output", async () => {
Expand Down

25 changes: 17 additions & 8 deletions
src/handlers/project/dev/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10,6 +10,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { AppIO, BrowserOpener, FileWatcher, PortChecker, startHttpServer } from "../../../io";
Expand DownExpand Up@@ -102,7 +103,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 flag("traces", "disable local OTEL trace collection", z.boolean().default(true)),
 flag(
 "mode",
 "how to run: browser (Agent Inspector web UI), headless (one agent in the terminal), or tui",
 "how to run: browser (Agent Inspector web UI), headless (agents stream to the terminal), or tui",
 z.enum(["browser", "headless", "tui"]).default("browser"),
 ),
 flag(
Expand DownExpand Up@@ -132,12 +133,6 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 );
 }
 const runtimes = selectRuntimes(project, flags.agent);
 if (flags.mode === "headless" && !flags.agent) {
 const available = runtimes.map((runtime) => runtime.name).join(", ");
 throw new InputValidationError(
 `--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: ${available}.`,
 );
 }
 if (runtimes.length > 1 && flags.port !== undefined) {
 throw new InputValidationError(
 "--port applies to a single runtime. Use --agent to select one.",
Expand DownExpand Up@@ -194,7 +189,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 return { ...env, ...otel };
 };

 if (flags.mode === "headless") {
 if (flags.mode === "headless" && flags.agent) {
 await runWithoutUi(
 config,
 runtimes[0]!,
Expand DownExpand Up@@ -227,6 +222,20 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 signal: controller.signal,
 });

 if (flags.mode === "headless") {
 void Promise.allSettled(runtimes.map((runtime) => supervisor.start(runtime.name)));
 for await (const { agentName, event } of supervisor.events()) {
@aidandaly24aidandaly24Aug 28, 2026

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I think normal Ctrl-C gets reported as a crash in this supervised headless path. The production process runner rejects with the child signal's UserCancellationError, so the supervisor emits Agent 'orders' crashed: Operation cancelled by user before the command exits 130. Could the supervisor treat an error from an already-aborted child signal as a normal stop? A test where the runner throws input.signal.reason on abort would cover the production behavior better than stayingRunner, which returns cleanly.
 renderAgentEvent(config.io, event, agentName, json);
 const phases = supervisor.snapshot();
 if (phases.every(({ phase }) => phase !== "starting" && phase !== "running")) {
 if (phases.some(({ phase }) => phase === "failed")) throw new SilentCLIError();
 break;
 }
 }
 controller.signal.throwIfAborted();
 return;
 }

 const uiPort = (
 await findFreePort(UI_DEFAULT_PORT, flags["ui-port"], config.checkPort, controller.signal)
 ).port;
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(dev): supervise every runtime in headless mode by tejaskash · Pull Request #2138 · aws/agentcore-cli · GitHub
Skip to content
feat(dev): supervise every runtime in headless mode#2138

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feat(dev): supervise every runtime in headless mode
#2138
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45a092e

feat(dev): supervise every runtime in headless mode


tejaskash Aug 28, 2026
ba8cddf

refactor(dev): drop the dead await on eager start results


tejaskash Aug 28, 2026

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97 changes: 80 additions & 17 deletions
src/handlers/project/dev/index.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -4,6 +4,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { HttpRequestHandler, PortChecker } from "../../../io";
Expand DownExpand Up@@ -45,6 +46,22 @@ function captureRunner(events: DevEvent[] = []) {
 return { runner, inputs };
}

/** A runner that emits `events` then stays alive until aborted, like a real dev server. */
function stayingRunner(events: DevEvent[] = []) {
 const inputs: DevServerInput[] = [];
 const runner: DevRunner = {
 run: async function* (input) {
 inputs.push(input);
 yield* events;
 if (input.signal.aborted) return;
 await new Promise<void>((resolve) =>
 input.signal.addEventListener("abort", () => resolve(), { once: true }),
 );
 },
 };
 return { runner, inputs };
}

function fakeCollector() {
 const starts: Parameters<DevProjectHandlerConfig["startTraceCollector"]>[0][] = [];
 const state = { closed: 0 };
Expand DownExpand Up@@ -120,6 +137,9 @@ function harness(options: HarnessOptions = {}) {
 resolve: async () =>
 options.reloadedRuntimes ? project(...options.reloadedRuntimes) : undefined,
 },
 waitReady: async () => {
 await Bun.sleep(5);
 },
 });
 const ctx = ValueContext.EmptyContext()
 .withValue(ProjectKey, options.project ?? project(runtime()))
Expand DownExpand Up@@ -167,16 +187,10 @@ async function inspectorStatus(subject: ReturnType<typeof harness>): Promise<{ n
describe("project dev selection and dispatch", () => {
 test.each([
 [project(), {}, "This project has no runtimes", InputValidationError],
 [
 project(runtime("orders")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders",
 InputValidationError,
 ],
 [
 project(runtime("orders"), runtime("support", "Container")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders, support",
 { port: 4567 },
 "--port applies to a single runtime. Use --agent to select one.",
 InputValidationError,
 ],
 [
Expand DownExpand Up@@ -237,6 +251,64 @@ describe("project dev selection and dispatch", () => {
 });
});

describe("project dev headless multi-agent", () => {
 const twoRuntimes = () => project(runtime("orders"), runtime("support", "Container"));

 /** Start a headless multi-agent run and give its agents time to reach "running". */
 async function supervised(subject: ReturnType<typeof harness>) {
 const pending = subject.run();
 pending.catch(() => undefined);
 await Bun.sleep(30);
 return { pending };
 }

 test("supervises every runtime with attributed output and per-runtime env", async () => {
 const codeZip = stayingRunner([{ type: "stdout", line: "orders says hi" }]);
 const container = stayingRunner();
 const subject = harness({ project: twoRuntimes(), codeZip, container });
 const { pending } = await supervised(subject);

 expect(codeZip.inputs).toHaveLength(1);
 expect(container.inputs).toHaveLength(1);
 expect(codeZip.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:43180",
 OTEL_SERVICE_NAME: "orders",
 });
 expect(container.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://host.docker.internal:43180",
 OTEL_SERVICE_NAME: "support",
 });
 expect(subject.io.stdout()).toContain("[orders] orders says hi");
 expect(subject.io.stderr()).toContain("Agent 'orders' is running on port");

 process.emit("SIGINT", "SIGINT");
 await expect(pending).rejects.toMatchObject({ exitCode: 130 });
 expect(subject.collector.state.closed).toBe(1);
 });

 test("one agent failing to start leaves the others running", async () => {
 const subject = harness({
 project: twoRuntimes(),
 codeZip: captureRunner([{ type: "status", message: "dying" }]),
 container: stayingRunner(),
 });
 const { pending } = await supervised(subject);

 expect(subject.io.stderr()).toContain("[orders] Agent 'orders' failed to start");
 expect(subject.io.stderr()).toContain("Agent 'support' is running on port");

 process.emit("SIGINT", "SIGINT");
 await pending.catch(() => undefined);
 });

 test("exits non-zero when every agent fails to start", async () => {
 const subject = harness({ project: twoRuntimes() });

 await expect(subject.run()).rejects.toBeInstanceOf(SilentCLIError);
 expect(subject.collector.state.closed).toBe(1);
 });
});

describe("project dev trace collection", () => {
 test("starts the collector, announces it, and points a CodeZip agent at loopback", async () => {
 const subject = harness();
Expand DownExpand Up@@ -396,15 +468,6 @@ describe("project dev Inspector UI mode", () => {
 "Port 9999 is already in use",
 );
 });

 test("--port with several runtimes is rejected", async () => {
 const subject = harness({
 project: project(runtime("orders"), runtime("support", "Container")),
 });
 await expect(subject.run({ mode: "browser", port: 4567 })).rejects.toThrow(
 "--port applies to a single runtime",
 );
 });
});

test("project dev renders attributed human and NDJSON output", async () => {
Expand Down

25 changes: 17 additions & 8 deletions
src/handlers/project/dev/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10,6 +10,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { AppIO, BrowserOpener, FileWatcher, PortChecker, startHttpServer } from "../../../io";
Expand DownExpand Up@@ -102,7 +103,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 flag("traces", "disable local OTEL trace collection", z.boolean().default(true)),
 flag(
 "mode",
 "how to run: browser (Agent Inspector web UI), headless (one agent in the terminal), or tui",
 "how to run: browser (Agent Inspector web UI), headless (agents stream to the terminal), or tui",
 z.enum(["browser", "headless", "tui"]).default("browser"),
 ),
 flag(
Expand DownExpand Up@@ -132,12 +133,6 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 );
 }
 const runtimes = selectRuntimes(project, flags.agent);
 if (flags.mode === "headless" && !flags.agent) {
 const available = runtimes.map((runtime) => runtime.name).join(", ");
 throw new InputValidationError(
 `--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: ${available}.`,
 );
 }
 if (runtimes.length > 1 && flags.port !== undefined) {
 throw new InputValidationError(
 "--port applies to a single runtime. Use --agent to select one.",
Expand DownExpand Up@@ -194,7 +189,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 return { ...env, ...otel };
 };

 if (flags.mode === "headless") {
 if (flags.mode === "headless" && flags.agent) {
 await runWithoutUi(
 config,
 runtimes[0]!,
Expand DownExpand Up@@ -227,6 +222,20 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 signal: controller.signal,
 });

 if (flags.mode === "headless") {
 void Promise.allSettled(runtimes.map((runtime) => supervisor.start(runtime.name)));
 for await (const { agentName, event } of supervisor.events()) {
@aidandaly24aidandaly24Aug 28, 2026

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I think normal Ctrl-C gets reported as a crash in this supervised headless path. The production process runner rejects with the child signal's UserCancellationError, so the supervisor emits Agent 'orders' crashed: Operation cancelled by user before the command exits 130. Could the supervisor treat an error from an already-aborted child signal as a normal stop? A test where the runner throws input.signal.reason on abort would cover the production behavior better than stayingRunner, which returns cleanly.
 renderAgentEvent(config.io, event, agentName, json);
 const phases = supervisor.snapshot();
 if (phases.every(({ phase }) => phase !== "starting" && phase !== "running")) {
 if (phases.some(({ phase }) => phase === "failed")) throw new SilentCLIError();
 break;
 }
 }
 controller.signal.throwIfAborted();
 return;
 }

 const uiPort = (
 await findFreePort(UI_DEFAULT_PORT, flags["ui-port"], config.checkPort, controller.signal)
 ).port;
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
feat(dev): supervise every runtime in headless mode by tejaskash · Pull Request #2138 · aws/agentcore-cli · GitHub
Skip to content
feat(dev): supervise every runtime in headless mode#2138

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feat(dev): supervise every runtime in headless mode
#2138
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45a092e

feat(dev): supervise every runtime in headless mode


tejaskash Aug 28, 2026
ba8cddf

refactor(dev): drop the dead await on eager start results


tejaskash Aug 28, 2026

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97 changes: 80 additions & 17 deletions
src/handlers/project/dev/index.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -4,6 +4,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { HttpRequestHandler, PortChecker } from "../../../io";
Expand DownExpand Up@@ -45,6 +46,22 @@ function captureRunner(events: DevEvent[] = []) {
 return { runner, inputs };
}

/** A runner that emits `events` then stays alive until aborted, like a real dev server. */
function stayingRunner(events: DevEvent[] = []) {
 const inputs: DevServerInput[] = [];
 const runner: DevRunner = {
 run: async function* (input) {
 inputs.push(input);
 yield* events;
 if (input.signal.aborted) return;
 await new Promise<void>((resolve) =>
 input.signal.addEventListener("abort", () => resolve(), { once: true }),
 );
 },
 };
 return { runner, inputs };
}

function fakeCollector() {
 const starts: Parameters<DevProjectHandlerConfig["startTraceCollector"]>[0][] = [];
 const state = { closed: 0 };
Expand DownExpand Up@@ -120,6 +137,9 @@ function harness(options: HarnessOptions = {}) {
 resolve: async () =>
 options.reloadedRuntimes ? project(...options.reloadedRuntimes) : undefined,
 },
 waitReady: async () => {
 await Bun.sleep(5);
 },
 });
 const ctx = ValueContext.EmptyContext()
 .withValue(ProjectKey, options.project ?? project(runtime()))
Expand DownExpand Up@@ -167,16 +187,10 @@ async function inspectorStatus(subject: ReturnType<typeof harness>): Promise<{ n
describe("project dev selection and dispatch", () => {
 test.each([
 [project(), {}, "This project has no runtimes", InputValidationError],
 [
 project(runtime("orders")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders",
 InputValidationError,
 ],
 [
 project(runtime("orders"), runtime("support", "Container")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders, support",
 { port: 4567 },
 "--port applies to a single runtime. Use --agent to select one.",
 InputValidationError,
 ],
 [
Expand DownExpand Up@@ -237,6 +251,64 @@ describe("project dev selection and dispatch", () => {
 });
});

describe("project dev headless multi-agent", () => {
 const twoRuntimes = () => project(runtime("orders"), runtime("support", "Container"));

 /** Start a headless multi-agent run and give its agents time to reach "running". */
 async function supervised(subject: ReturnType<typeof harness>) {
 const pending = subject.run();
 pending.catch(() => undefined);
 await Bun.sleep(30);
 return { pending };
 }

 test("supervises every runtime with attributed output and per-runtime env", async () => {
 const codeZip = stayingRunner([{ type: "stdout", line: "orders says hi" }]);
 const container = stayingRunner();
 const subject = harness({ project: twoRuntimes(), codeZip, container });
 const { pending } = await supervised(subject);

 expect(codeZip.inputs).toHaveLength(1);
 expect(container.inputs).toHaveLength(1);
 expect(codeZip.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:43180",
 OTEL_SERVICE_NAME: "orders",
 });
 expect(container.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://host.docker.internal:43180",
 OTEL_SERVICE_NAME: "support",
 });
 expect(subject.io.stdout()).toContain("[orders] orders says hi");
 expect(subject.io.stderr()).toContain("Agent 'orders' is running on port");

 process.emit("SIGINT", "SIGINT");
 await expect(pending).rejects.toMatchObject({ exitCode: 130 });
 expect(subject.collector.state.closed).toBe(1);
 });

 test("one agent failing to start leaves the others running", async () => {
 const subject = harness({
 project: twoRuntimes(),
 codeZip: captureRunner([{ type: "status", message: "dying" }]),
 container: stayingRunner(),
 });
 const { pending } = await supervised(subject);

 expect(subject.io.stderr()).toContain("[orders] Agent 'orders' failed to start");
 expect(subject.io.stderr()).toContain("Agent 'support' is running on port");

 process.emit("SIGINT", "SIGINT");
 await pending.catch(() => undefined);
 });

 test("exits non-zero when every agent fails to start", async () => {
 const subject = harness({ project: twoRuntimes() });

 await expect(subject.run()).rejects.toBeInstanceOf(SilentCLIError);
 expect(subject.collector.state.closed).toBe(1);
 });
});

describe("project dev trace collection", () => {
 test("starts the collector, announces it, and points a CodeZip agent at loopback", async () => {
 const subject = harness();
Expand DownExpand Up@@ -396,15 +468,6 @@ describe("project dev Inspector UI mode", () => {
 "Port 9999 is already in use",
 );
 });

 test("--port with several runtimes is rejected", async () => {
 const subject = harness({
 project: project(runtime("orders"), runtime("support", "Container")),
 });
 await expect(subject.run({ mode: "browser", port: 4567 })).rejects.toThrow(
 "--port applies to a single runtime",
 );
 });
});

test("project dev renders attributed human and NDJSON output", async () => {
Expand Down

25 changes: 17 additions & 8 deletions
src/handlers/project/dev/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10,6 +10,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { AppIO, BrowserOpener, FileWatcher, PortChecker, startHttpServer } from "../../../io";
Expand DownExpand Up@@ -102,7 +103,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 flag("traces", "disable local OTEL trace collection", z.boolean().default(true)),
 flag(
 "mode",
 "how to run: browser (Agent Inspector web UI), headless (one agent in the terminal), or tui",
 "how to run: browser (Agent Inspector web UI), headless (agents stream to the terminal), or tui",
 z.enum(["browser", "headless", "tui"]).default("browser"),
 ),
 flag(
Expand DownExpand Up@@ -132,12 +133,6 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 );
 }
 const runtimes = selectRuntimes(project, flags.agent);
 if (flags.mode === "headless" && !flags.agent) {
 const available = runtimes.map((runtime) => runtime.name).join(", ");
 throw new InputValidationError(
 `--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: ${available}.`,
 );
 }
 if (runtimes.length > 1 && flags.port !== undefined) {
 throw new InputValidationError(
 "--port applies to a single runtime. Use --agent to select one.",
Expand DownExpand Up@@ -194,7 +189,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 return { ...env, ...otel };
 };

 if (flags.mode === "headless") {
 if (flags.mode === "headless" && flags.agent) {
 await runWithoutUi(
 config,
 runtimes[0]!,
Expand DownExpand Up@@ -227,6 +222,20 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 signal: controller.signal,
 });

 if (flags.mode === "headless") {
 void Promise.allSettled(runtimes.map((runtime) => supervisor.start(runtime.name)));
 for await (const { agentName, event } of supervisor.events()) {
@aidandaly24aidandaly24Aug 28, 2026

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I think normal Ctrl-C gets reported as a crash in this supervised headless path. The production process runner rejects with the child signal's UserCancellationError, so the supervisor emits Agent 'orders' crashed: Operation cancelled by user before the command exits 130. Could the supervisor treat an error from an already-aborted child signal as a normal stop? A test where the runner throws input.signal.reason on abort would cover the production behavior better than stayingRunner, which returns cleanly.
 renderAgentEvent(config.io, event, agentName, json);
 const phases = supervisor.snapshot();
 if (phases.every(({ phase }) => phase !== "starting" && phase !== "running")) {
 if (phases.some(({ phase }) => phase === "failed")) throw new SilentCLIError();
 break;
 }
 }
 controller.signal.throwIfAborted();
 return;
 }

 const uiPort = (
 await findFreePort(UI_DEFAULT_PORT, flags["ui-port"], config.checkPort, controller.signal)
 ).port;
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(dev): supervise every runtime in headless mode by tejaskash · Pull Request #2138 · aws/agentcore-cli · GitHub
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feat(dev): supervise every runtime in headless mode#2138

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feat(dev): supervise every runtime in headless mode
#2138
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feat(dev): supervise every runtime in headless mode


tejaskash Aug 28, 2026
ba8cddf

refactor(dev): drop the dead await on eager start results


tejaskash Aug 28, 2026

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97 changes: 80 additions & 17 deletions
src/handlers/project/dev/index.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -4,6 +4,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { HttpRequestHandler, PortChecker } from "../../../io";
Expand DownExpand Up@@ -45,6 +46,22 @@ function captureRunner(events: DevEvent[] = []) {
 return { runner, inputs };
}

/** A runner that emits `events` then stays alive until aborted, like a real dev server. */
function stayingRunner(events: DevEvent[] = []) {
 const inputs: DevServerInput[] = [];
 const runner: DevRunner = {
 run: async function* (input) {
 inputs.push(input);
 yield* events;
 if (input.signal.aborted) return;
 await new Promise<void>((resolve) =>
 input.signal.addEventListener("abort", () => resolve(), { once: true }),
 );
 },
 };
 return { runner, inputs };
}

function fakeCollector() {
 const starts: Parameters<DevProjectHandlerConfig["startTraceCollector"]>[0][] = [];
 const state = { closed: 0 };
Expand DownExpand Up@@ -120,6 +137,9 @@ function harness(options: HarnessOptions = {}) {
 resolve: async () =>
 options.reloadedRuntimes ? project(...options.reloadedRuntimes) : undefined,
 },
 waitReady: async () => {
 await Bun.sleep(5);
 },
 });
 const ctx = ValueContext.EmptyContext()
 .withValue(ProjectKey, options.project ?? project(runtime()))
Expand DownExpand Up@@ -167,16 +187,10 @@ async function inspectorStatus(subject: ReturnType<typeof harness>): Promise<{ n
describe("project dev selection and dispatch", () => {
 test.each([
 [project(), {}, "This project has no runtimes", InputValidationError],
 [
 project(runtime("orders")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders",
 InputValidationError,
 ],
 [
 project(runtime("orders"), runtime("support", "Container")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders, support",
 { port: 4567 },
 "--port applies to a single runtime. Use --agent to select one.",
 InputValidationError,
 ],
 [
Expand DownExpand Up@@ -237,6 +251,64 @@ describe("project dev selection and dispatch", () => {
 });
});

describe("project dev headless multi-agent", () => {
 const twoRuntimes = () => project(runtime("orders"), runtime("support", "Container"));

 /** Start a headless multi-agent run and give its agents time to reach "running". */
 async function supervised(subject: ReturnType<typeof harness>) {
 const pending = subject.run();
 pending.catch(() => undefined);
 await Bun.sleep(30);
 return { pending };
 }

 test("supervises every runtime with attributed output and per-runtime env", async () => {
 const codeZip = stayingRunner([{ type: "stdout", line: "orders says hi" }]);
 const container = stayingRunner();
 const subject = harness({ project: twoRuntimes(), codeZip, container });
 const { pending } = await supervised(subject);

 expect(codeZip.inputs).toHaveLength(1);
 expect(container.inputs).toHaveLength(1);
 expect(codeZip.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:43180",
 OTEL_SERVICE_NAME: "orders",
 });
 expect(container.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://host.docker.internal:43180",
 OTEL_SERVICE_NAME: "support",
 });
 expect(subject.io.stdout()).toContain("[orders] orders says hi");
 expect(subject.io.stderr()).toContain("Agent 'orders' is running on port");

 process.emit("SIGINT", "SIGINT");
 await expect(pending).rejects.toMatchObject({ exitCode: 130 });
 expect(subject.collector.state.closed).toBe(1);
 });

 test("one agent failing to start leaves the others running", async () => {
 const subject = harness({
 project: twoRuntimes(),
 codeZip: captureRunner([{ type: "status", message: "dying" }]),
 container: stayingRunner(),
 });
 const { pending } = await supervised(subject);

 expect(subject.io.stderr()).toContain("[orders] Agent 'orders' failed to start");
 expect(subject.io.stderr()).toContain("Agent 'support' is running on port");

 process.emit("SIGINT", "SIGINT");
 await pending.catch(() => undefined);
 });

 test("exits non-zero when every agent fails to start", async () => {
 const subject = harness({ project: twoRuntimes() });

 await expect(subject.run()).rejects.toBeInstanceOf(SilentCLIError);
 expect(subject.collector.state.closed).toBe(1);
 });
});

describe("project dev trace collection", () => {
 test("starts the collector, announces it, and points a CodeZip agent at loopback", async () => {
 const subject = harness();
Expand DownExpand Up@@ -396,15 +468,6 @@ describe("project dev Inspector UI mode", () => {
 "Port 9999 is already in use",
 );
 });

 test("--port with several runtimes is rejected", async () => {
 const subject = harness({
 project: project(runtime("orders"), runtime("support", "Container")),
 });
 await expect(subject.run({ mode: "browser", port: 4567 })).rejects.toThrow(
 "--port applies to a single runtime",
 );
 });
});

test("project dev renders attributed human and NDJSON output", async () => {
Expand Down

25 changes: 17 additions & 8 deletions
src/handlers/project/dev/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10,6 +10,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { AppIO, BrowserOpener, FileWatcher, PortChecker, startHttpServer } from "../../../io";
Expand DownExpand Up@@ -102,7 +103,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 flag("traces", "disable local OTEL trace collection", z.boolean().default(true)),
 flag(
 "mode",
 "how to run: browser (Agent Inspector web UI), headless (one agent in the terminal), or tui",
 "how to run: browser (Agent Inspector web UI), headless (agents stream to the terminal), or tui",
 z.enum(["browser", "headless", "tui"]).default("browser"),
 ),
 flag(
Expand DownExpand Up@@ -132,12 +133,6 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 );
 }
 const runtimes = selectRuntimes(project, flags.agent);
 if (flags.mode === "headless" && !flags.agent) {
 const available = runtimes.map((runtime) => runtime.name).join(", ");
 throw new InputValidationError(
 `--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: ${available}.`,
 );
 }
 if (runtimes.length > 1 && flags.port !== undefined) {
 throw new InputValidationError(
 "--port applies to a single runtime. Use --agent to select one.",
Expand DownExpand Up@@ -194,7 +189,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 return { ...env, ...otel };
 };

 if (flags.mode === "headless") {
 if (flags.mode === "headless" && flags.agent) {
 await runWithoutUi(
 config,
 runtimes[0]!,
Expand DownExpand Up@@ -227,6 +222,20 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 signal: controller.signal,
 });

 if (flags.mode === "headless") {
 void Promise.allSettled(runtimes.map((runtime) => supervisor.start(runtime.name)));
 for await (const { agentName, event } of supervisor.events()) {
@aidandaly24aidandaly24Aug 28, 2026

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I think normal Ctrl-C gets reported as a crash in this supervised headless path. The production process runner rejects with the child signal's UserCancellationError, so the supervisor emits Agent 'orders' crashed: Operation cancelled by user before the command exits 130. Could the supervisor treat an error from an already-aborted child signal as a normal stop? A test where the runner throws input.signal.reason on abort would cover the production behavior better than stayingRunner, which returns cleanly.
 renderAgentEvent(config.io, event, agentName, json);
 const phases = supervisor.snapshot();
 if (phases.every(({ phase }) => phase !== "starting" && phase !== "running")) {
 if (phases.some(({ phase }) => phase === "failed")) throw new SilentCLIError();
 break;
 }
 }
 controller.signal.throwIfAborted();
 return;
 }

 const uiPort = (
 await findFreePort(UI_DEFAULT_PORT, flags["ui-port"], config.checkPort, controller.signal)
 ).port;
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(dev): supervise every runtime in headless mode by tejaskash · Pull Request #2138 · aws/agentcore-cli · GitHub
Skip to content
feat(dev): supervise every runtime in headless mode#2138

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Choose a base branch

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feat(dev): supervise every runtime in headless mode
#2138
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45a092e

feat(dev): supervise every runtime in headless mode


tejaskash Aug 28, 2026
ba8cddf

refactor(dev): drop the dead await on eager start results


tejaskash Aug 28, 2026

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97 changes: 80 additions & 17 deletions
src/handlers/project/dev/index.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -4,6 +4,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { HttpRequestHandler, PortChecker } from "../../../io";
Expand DownExpand Up@@ -45,6 +46,22 @@ function captureRunner(events: DevEvent[] = []) {
 return { runner, inputs };
}

/** A runner that emits `events` then stays alive until aborted, like a real dev server. */
function stayingRunner(events: DevEvent[] = []) {
 const inputs: DevServerInput[] = [];
 const runner: DevRunner = {
 run: async function* (input) {
 inputs.push(input);
 yield* events;
 if (input.signal.aborted) return;
 await new Promise<void>((resolve) =>
 input.signal.addEventListener("abort", () => resolve(), { once: true }),
 );
 },
 };
 return { runner, inputs };
}

function fakeCollector() {
 const starts: Parameters<DevProjectHandlerConfig["startTraceCollector"]>[0][] = [];
 const state = { closed: 0 };
Expand DownExpand Up@@ -120,6 +137,9 @@ function harness(options: HarnessOptions = {}) {
 resolve: async () =>
 options.reloadedRuntimes ? project(...options.reloadedRuntimes) : undefined,
 },
 waitReady: async () => {
 await Bun.sleep(5);
 },
 });
 const ctx = ValueContext.EmptyContext()
 .withValue(ProjectKey, options.project ?? project(runtime()))
Expand DownExpand Up@@ -167,16 +187,10 @@ async function inspectorStatus(subject: ReturnType<typeof harness>): Promise<{ n
describe("project dev selection and dispatch", () => {
 test.each([
 [project(), {}, "This project has no runtimes", InputValidationError],
 [
 project(runtime("orders")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders",
 InputValidationError,
 ],
 [
 project(runtime("orders"), runtime("support", "Container")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders, support",
 { port: 4567 },
 "--port applies to a single runtime. Use --agent to select one.",
 InputValidationError,
 ],
 [
Expand DownExpand Up@@ -237,6 +251,64 @@ describe("project dev selection and dispatch", () => {
 });
});

describe("project dev headless multi-agent", () => {
 const twoRuntimes = () => project(runtime("orders"), runtime("support", "Container"));

 /** Start a headless multi-agent run and give its agents time to reach "running". */
 async function supervised(subject: ReturnType<typeof harness>) {
 const pending = subject.run();
 pending.catch(() => undefined);
 await Bun.sleep(30);
 return { pending };
 }

 test("supervises every runtime with attributed output and per-runtime env", async () => {
 const codeZip = stayingRunner([{ type: "stdout", line: "orders says hi" }]);
 const container = stayingRunner();
 const subject = harness({ project: twoRuntimes(), codeZip, container });
 const { pending } = await supervised(subject);

 expect(codeZip.inputs).toHaveLength(1);
 expect(container.inputs).toHaveLength(1);
 expect(codeZip.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:43180",
 OTEL_SERVICE_NAME: "orders",
 });
 expect(container.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://host.docker.internal:43180",
 OTEL_SERVICE_NAME: "support",
 });
 expect(subject.io.stdout()).toContain("[orders] orders says hi");
 expect(subject.io.stderr()).toContain("Agent 'orders' is running on port");

 process.emit("SIGINT", "SIGINT");
 await expect(pending).rejects.toMatchObject({ exitCode: 130 });
 expect(subject.collector.state.closed).toBe(1);
 });

 test("one agent failing to start leaves the others running", async () => {
 const subject = harness({
 project: twoRuntimes(),
 codeZip: captureRunner([{ type: "status", message: "dying" }]),
 container: stayingRunner(),
 });
 const { pending } = await supervised(subject);

 expect(subject.io.stderr()).toContain("[orders] Agent 'orders' failed to start");
 expect(subject.io.stderr()).toContain("Agent 'support' is running on port");

 process.emit("SIGINT", "SIGINT");
 await pending.catch(() => undefined);
 });

 test("exits non-zero when every agent fails to start", async () => {
 const subject = harness({ project: twoRuntimes() });

 await expect(subject.run()).rejects.toBeInstanceOf(SilentCLIError);
 expect(subject.collector.state.closed).toBe(1);
 });
});

describe("project dev trace collection", () => {
 test("starts the collector, announces it, and points a CodeZip agent at loopback", async () => {
 const subject = harness();
Expand DownExpand Up@@ -396,15 +468,6 @@ describe("project dev Inspector UI mode", () => {
 "Port 9999 is already in use",
 );
 });

 test("--port with several runtimes is rejected", async () => {
 const subject = harness({
 project: project(runtime("orders"), runtime("support", "Container")),
 });
 await expect(subject.run({ mode: "browser", port: 4567 })).rejects.toThrow(
 "--port applies to a single runtime",
 );
 });
});

test("project dev renders attributed human and NDJSON output", async () => {
Expand Down

25 changes: 17 additions & 8 deletions
src/handlers/project/dev/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10,6 +10,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { AppIO, BrowserOpener, FileWatcher, PortChecker, startHttpServer } from "../../../io";
Expand DownExpand Up@@ -102,7 +103,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 flag("traces", "disable local OTEL trace collection", z.boolean().default(true)),
 flag(
 "mode",
 "how to run: browser (Agent Inspector web UI), headless (one agent in the terminal), or tui",
 "how to run: browser (Agent Inspector web UI), headless (agents stream to the terminal), or tui",
 z.enum(["browser", "headless", "tui"]).default("browser"),
 ),
 flag(
Expand DownExpand Up@@ -132,12 +133,6 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 );
 }
 const runtimes = selectRuntimes(project, flags.agent);
 if (flags.mode === "headless" && !flags.agent) {
 const available = runtimes.map((runtime) => runtime.name).join(", ");
 throw new InputValidationError(
 `--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: ${available}.`,
 );
 }
 if (runtimes.length > 1 && flags.port !== undefined) {
 throw new InputValidationError(
 "--port applies to a single runtime. Use --agent to select one.",
Expand DownExpand Up@@ -194,7 +189,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 return { ...env, ...otel };
 };

 if (flags.mode === "headless") {
 if (flags.mode === "headless" && flags.agent) {
 await runWithoutUi(
 config,
 runtimes[0]!,
Expand DownExpand Up@@ -227,6 +222,20 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 signal: controller.signal,
 });

 if (flags.mode === "headless") {
 void Promise.allSettled(runtimes.map((runtime) => supervisor.start(runtime.name)));
 for await (const { agentName, event } of supervisor.events()) {
@aidandaly24aidandaly24Aug 28, 2026

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I think normal Ctrl-C gets reported as a crash in this supervised headless path. The production process runner rejects with the child signal's UserCancellationError, so the supervisor emits Agent 'orders' crashed: Operation cancelled by user before the command exits 130. Could the supervisor treat an error from an already-aborted child signal as a normal stop? A test where the runner throws input.signal.reason on abort would cover the production behavior better than stayingRunner, which returns cleanly.
 renderAgentEvent(config.io, event, agentName, json);
 const phases = supervisor.snapshot();
 if (phases.every(({ phase }) => phase !== "starting" && phase !== "running")) {
 if (phases.some(({ phase }) => phase === "failed")) throw new SilentCLIError();
 break;
 }
 }
 controller.signal.throwIfAborted();
 return;
 }

 const uiPort = (
 await findFreePort(UI_DEFAULT_PORT, flags["ui-port"], config.checkPort, controller.signal)
 ).port;
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
feat(dev): supervise every runtime in headless mode by tejaskash · Pull Request #2138 · aws/agentcore-cli · GitHub
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feat(dev): supervise every runtime in headless mode
#2138
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45a092e

feat(dev): supervise every runtime in headless mode


tejaskash Aug 28, 2026
ba8cddf

refactor(dev): drop the dead await on eager start results


tejaskash Aug 28, 2026

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97 changes: 80 additions & 17 deletions
src/handlers/project/dev/index.test.ts

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Original file line numberDiff line numberDiff line change
Expand Up@@ -4,6 +4,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { HttpRequestHandler, PortChecker } from "../../../io";
Expand DownExpand Up@@ -45,6 +46,22 @@ function captureRunner(events: DevEvent[] = []) {
 return { runner, inputs };
}

/** A runner that emits `events` then stays alive until aborted, like a real dev server. */
function stayingRunner(events: DevEvent[] = []) {
 const inputs: DevServerInput[] = [];
 const runner: DevRunner = {
 run: async function* (input) {
 inputs.push(input);
 yield* events;
 if (input.signal.aborted) return;
 await new Promise<void>((resolve) =>
 input.signal.addEventListener("abort", () => resolve(), { once: true }),
 );
 },
 };
 return { runner, inputs };
}

function fakeCollector() {
 const starts: Parameters<DevProjectHandlerConfig["startTraceCollector"]>[0][] = [];
 const state = { closed: 0 };
Expand DownExpand Up@@ -120,6 +137,9 @@ function harness(options: HarnessOptions = {}) {
 resolve: async () =>
 options.reloadedRuntimes ? project(...options.reloadedRuntimes) : undefined,
 },
 waitReady: async () => {
 await Bun.sleep(5);
 },
 });
 const ctx = ValueContext.EmptyContext()
 .withValue(ProjectKey, options.project ?? project(runtime()))
Expand DownExpand Up@@ -167,16 +187,10 @@ async function inspectorStatus(subject: ReturnType<typeof harness>): Promise<{ n
describe("project dev selection and dispatch", () => {
 test.each([
 [project(), {}, "This project has no runtimes", InputValidationError],
 [
 project(runtime("orders")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders",
 InputValidationError,
 ],
 [
 project(runtime("orders"), runtime("support", "Container")),
 {},
 "--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: orders, support",
 { port: 4567 },
 "--port applies to a single runtime. Use --agent to select one.",
 InputValidationError,
 ],
 [
Expand DownExpand Up@@ -237,6 +251,64 @@ describe("project dev selection and dispatch", () => {
 });
});

describe("project dev headless multi-agent", () => {
 const twoRuntimes = () => project(runtime("orders"), runtime("support", "Container"));

 /** Start a headless multi-agent run and give its agents time to reach "running". */
 async function supervised(subject: ReturnType<typeof harness>) {
 const pending = subject.run();
 pending.catch(() => undefined);
 await Bun.sleep(30);
 return { pending };
 }

 test("supervises every runtime with attributed output and per-runtime env", async () => {
 const codeZip = stayingRunner([{ type: "stdout", line: "orders says hi" }]);
 const container = stayingRunner();
 const subject = harness({ project: twoRuntimes(), codeZip, container });
 const { pending } = await supervised(subject);

 expect(codeZip.inputs).toHaveLength(1);
 expect(container.inputs).toHaveLength(1);
 expect(codeZip.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://127.0.0.1:43180",
 OTEL_SERVICE_NAME: "orders",
 });
 expect(container.inputs[0]!.env).toMatchObject({
 OTEL_EXPORTER_OTLP_ENDPOINT: "http://host.docker.internal:43180",
 OTEL_SERVICE_NAME: "support",
 });
 expect(subject.io.stdout()).toContain("[orders] orders says hi");
 expect(subject.io.stderr()).toContain("Agent 'orders' is running on port");

 process.emit("SIGINT", "SIGINT");
 await expect(pending).rejects.toMatchObject({ exitCode: 130 });
 expect(subject.collector.state.closed).toBe(1);
 });

 test("one agent failing to start leaves the others running", async () => {
 const subject = harness({
 project: twoRuntimes(),
 codeZip: captureRunner([{ type: "status", message: "dying" }]),
 container: stayingRunner(),
 });
 const { pending } = await supervised(subject);

 expect(subject.io.stderr()).toContain("[orders] Agent 'orders' failed to start");
 expect(subject.io.stderr()).toContain("Agent 'support' is running on port");

 process.emit("SIGINT", "SIGINT");
 await pending.catch(() => undefined);
 });

 test("exits non-zero when every agent fails to start", async () => {
 const subject = harness({ project: twoRuntimes() });

 await expect(subject.run()).rejects.toBeInstanceOf(SilentCLIError);
 expect(subject.collector.state.closed).toBe(1);
 });
});

describe("project dev trace collection", () => {
 test("starts the collector, announces it, and points a CodeZip agent at loopback", async () => {
 const subject = harness();
Expand DownExpand Up@@ -396,15 +468,6 @@ describe("project dev Inspector UI mode", () => {
 "Port 9999 is already in use",
 );
 });

 test("--port with several runtimes is rejected", async () => {
 const subject = harness({
 project: project(runtime("orders"), runtime("support", "Container")),
 });
 await expect(subject.run({ mode: "browser", port: 4567 })).rejects.toThrow(
 "--port applies to a single runtime",
 );
 });
});

test("project dev renders attributed human and NDJSON output", async () => {
Expand Down

25 changes: 17 additions & 8 deletions
src/handlers/project/dev/index.ts

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Original file line numberDiff line numberDiff line change
Expand Up@@ -10,6 +10,7 @@ import type { ProjectRuntime } from "../../../projectSchemas/runtime";
import {
 InputValidationError,
 ResourceNotFoundError,
 SilentCLIError,
 UserCancellationError,
} from "../../../errors";
import type { AppIO, BrowserOpener, FileWatcher, PortChecker, startHttpServer } from "../../../io";
Expand DownExpand Up@@ -102,7 +103,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 flag("traces", "disable local OTEL trace collection", z.boolean().default(true)),
 flag(
 "mode",
 "how to run: browser (Agent Inspector web UI), headless (one agent in the terminal), or tui",
 "how to run: browser (Agent Inspector web UI), headless (agents stream to the terminal), or tui",
 z.enum(["browser", "headless", "tui"]).default("browser"),
 ),
 flag(
Expand DownExpand Up@@ -132,12 +133,6 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 );
 }
 const runtimes = selectRuntimes(project, flags.agent);
 if (flags.mode === "headless" && !flags.agent) {
 const available = runtimes.map((runtime) => runtime.name).join(", ");
 throw new InputValidationError(
 `--mode headless runs a single agent in the terminal. Pass --agent <name> to choose which one. Available: ${available}.`,
 );
 }
 if (runtimes.length > 1 && flags.port !== undefined) {
 throw new InputValidationError(
 "--port applies to a single runtime. Use --agent to select one.",
Expand DownExpand Up@@ -194,7 +189,7 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 return { ...env, ...otel };
 };

 if (flags.mode === "headless") {
 if (flags.mode === "headless" && flags.agent) {
 await runWithoutUi(
 config,
 runtimes[0]!,
Expand DownExpand Up@@ -227,6 +222,20 @@ export const createDevProjectHandler = (config: DevProjectHandlerConfig) =>
 signal: controller.signal,
 });

 if (flags.mode === "headless") {
 void Promise.allSettled(runtimes.map((runtime) => supervisor.start(runtime.name)));
 for await (const { agentName, event } of supervisor.events()) {
@aidandaly24aidandaly24Aug 28, 2026

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I think normal Ctrl-C gets reported as a crash in this supervised headless path. The production process runner rejects with the child signal's UserCancellationError, so the supervisor emits Agent 'orders' crashed: Operation cancelled by user before the command exits 130. Could the supervisor treat an error from an already-aborted child signal as a normal stop? A test where the runner throws input.signal.reason on abort would cover the production behavior better than stayingRunner, which returns cleanly.
 renderAgentEvent(config.io, event, agentName, json);
 const phases = supervisor.snapshot();
 if (phases.every(({ phase }) => phase !== "starting" && phase !== "running")) {
 if (phases.some(({ phase }) => phase === "failed")) throw new SilentCLIError();
 break;
 }
 }
 controller.signal.throwIfAborted();
 return;
 }

 const uiPort = (
 await findFreePort(UI_DEFAULT_PORT, flags["ui-port"], config.checkPort, controller.signal)
 ).port;
Expand Down
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