diff --git a/docs/gateway/index.md b/docs/gateway/index.md
index de553aa2d..a9f0a70b9 100644
--- a/docs/gateway/index.md
+++ b/docs/gateway/index.md
@@ -28,6 +28,7 @@ pnpm gateway:watch
   - Disable with `gateway.reload.mode="off"`.
 - Binds WebSocket control plane to `127.0.0.1:<port>` (default 18789).
 - The same port also serves HTTP (control UI, hooks, A2UI). Single-port multiplex.
+  - OpenAI-compatible HTTP API: [`/v1/chat/completions`](/gateway/openai-http-api).
 - Starts a Canvas file server by default on `canvasHost.port` (default `18793`), serving `http://<gateway-host>:18793/__clawdbot__/canvas/` from `~/clawd/canvas`. Disable with `canvasHost.enabled=false` or `CLAWDBOT_SKIP_CANVAS_HOST=1`.
 - Logs to stdout; use launchd/systemd to keep it alive and rotate logs.
 - Pass `--verbose` to mirror debug logging (handshakes, req/res, events) from the log file into stdio when troubleshooting.
diff --git a/docs/gateway/openai-http-api.md b/docs/gateway/openai-http-api.md
new file mode 100644
index 000000000..519158d11
--- /dev/null
+++ b/docs/gateway/openai-http-api.md
@@ -0,0 +1,72 @@
+---
+summary: "Expose an OpenAI-compatible /v1/chat/completions HTTP endpoint from the Gateway"
+read_when:
+  - Integrating tools that expect OpenAI Chat Completions
+---
+# OpenAI-compatible HTTP API
+
+Clawdbot’s Gateway can serve a small OpenAI-compatible endpoint:
+
+- `POST /v1/chat/completions`
+- Same port as the Gateway (WS + HTTP multiplex): `http://<gateway-host>:<port>/v1/chat/completions`
+
+## Authentication
+
+Uses the Gateway auth configuration. Send a bearer token:
+
+- `Authorization: Bearer <token>`
+
+Notes:
+- When `gateway.auth.mode="token"`, use `gateway.auth.token` (or `CLAWDBOT_GATEWAY_TOKEN`).
+- When `gateway.auth.mode="password"`, use `gateway.auth.password` (or `CLAWDBOT_GATEWAY_PASSWORD`).
+
+## Choosing an agent
+
+Target a specific Clawdbot agent by id:
+
+- `x-clawdbot-agent-id: <agentId>` (default: `main`)
+
+Advanced:
+- `x-clawdbot-session-key: <sessionKey>` to fully control session routing.
+
+## Session behavior
+
+By default the endpoint is **stateless per request** (a new session key is generated each call).
+
+If the request includes an OpenAI `user` string, the Gateway derives a stable session key from it, so repeated calls can share an agent session.
+
+## Streaming (SSE)
+
+Set `stream: true` to receive Server-Sent Events (SSE):
+
+- `Content-Type: text/event-stream`
+- Each event line is `data: <json>`
+- Stream ends with `data: [DONE]`
+
+## Examples
+
+Non-streaming:
+```bash
+curl -sS http://127.0.0.1:18789/v1/chat/completions \
+  -H 'Authorization: Bearer YOUR_TOKEN' \
+  -H 'Content-Type: application/json' \
+  -H 'x-clawdbot-agent-id: main' \
+  -d '{
+    "model": "clawdbot",
+    "messages": [{"role":"user","content":"hi"}]
+  }'
+```
+
+Streaming:
+```bash
+curl -N http://127.0.0.1:18789/v1/chat/completions \
+  -H 'Authorization: Bearer YOUR_TOKEN' \
+  -H 'Content-Type: application/json' \
+  -H 'x-clawdbot-agent-id: main' \
+  -d '{
+    "model": "clawdbot",
+    "stream": true,
+    "messages": [{"role":"user","content":"hi"}]
+  }'
+```
+
diff --git a/src/gateway/openai-http.e2e.test.ts b/src/gateway/openai-http.e2e.test.ts
new file mode 100644
index 000000000..ec85285d5
--- /dev/null
+++ b/src/gateway/openai-http.e2e.test.ts
@@ -0,0 +1,297 @@
+import { describe, expect, it } from "vitest";
+
+import { emitAgentEvent } from "../infra/agent-events.js";
+import {
+  agentCommand,
+  getFreePort,
+  installGatewayTestHooks,
+} from "./test-helpers.js";
+
+installGatewayTestHooks();
+
+async function startServer(port: number) {
+  const { startGatewayServer } = await import("./server.js");
+  return await startGatewayServer(port, {
+    host: "127.0.0.1",
+    auth: { mode: "token", token: "secret" },
+    controlUiEnabled: false,
+  });
+}
+
+async function postChatCompletions(
+  port: number,
+  body: unknown,
+  headers?: Record<string, string>,
+) {
+  const res = await fetch(`http://127.0.0.1:${port}/v1/chat/completions`, {
+    method: "POST",
+    headers: {
+      "content-type": "application/json",
+      authorization: "Bearer secret",
+      ...headers,
+    },
+    body: JSON.stringify(body),
+  });
+  return res;
+}
+
+function parseSseDataLines(text: string): string[] {
+  return text
+    .split("\n")
+    .map((line) => line.trim())
+    .filter((line) => line.startsWith("data: "))
+    .map((line) => line.slice("data: ".length));
+}
+
+describe("OpenAI-compatible HTTP API (e2e)", () => {
+  it("rejects non-POST", async () => {
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await fetch(`http://127.0.0.1:${port}/v1/chat/completions`, {
+        method: "GET",
+        headers: { authorization: "Bearer secret" },
+      });
+      expect(res.status).toBe(405);
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("rejects missing auth", async () => {
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await fetch(`http://127.0.0.1:${port}/v1/chat/completions`, {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({ messages: [{ role: "user", content: "hi" }] }),
+      });
+      expect(res.status).toBe(401);
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("routes to a specific agent via header", async () => {
+    agentCommand.mockResolvedValueOnce({
+      payloads: [{ text: "hello" }],
+    } as never);
+
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await postChatCompletions(
+        port,
+        { model: "clawdbot", messages: [{ role: "user", content: "hi" }] },
+        { "x-clawdbot-agent-id": "beta" },
+      );
+      expect(res.status).toBe(200);
+
+      expect(agentCommand).toHaveBeenCalledTimes(1);
+      const [opts] = agentCommand.mock.calls[0] ?? [];
+      expect(
+        (opts as { sessionKey?: string } | undefined)?.sessionKey ?? "",
+      ).toMatch(/^agent:beta:/);
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("honors x-clawdbot-session-key override", async () => {
+    agentCommand.mockResolvedValueOnce({
+      payloads: [{ text: "hello" }],
+    } as never);
+
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await postChatCompletions(
+        port,
+        { model: "clawdbot", messages: [{ role: "user", content: "hi" }] },
+        {
+          "x-clawdbot-agent-id": "beta",
+          "x-clawdbot-session-key": "agent:beta:openai:custom",
+        },
+      );
+      expect(res.status).toBe(200);
+
+      const [opts] = agentCommand.mock.calls[0] ?? [];
+      expect((opts as { sessionKey?: string } | undefined)?.sessionKey).toBe(
+        "agent:beta:openai:custom",
+      );
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("uses OpenAI user for a stable session key", async () => {
+    agentCommand.mockResolvedValueOnce({
+      payloads: [{ text: "hello" }],
+    } as never);
+
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await postChatCompletions(port, {
+        user: "alice",
+        model: "clawdbot",
+        messages: [{ role: "user", content: "hi" }],
+      });
+      expect(res.status).toBe(200);
+
+      const [opts] = agentCommand.mock.calls[0] ?? [];
+      expect(
+        (opts as { sessionKey?: string } | undefined)?.sessionKey ?? "",
+      ).toContain("openai-user:alice");
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("extracts user message text from array content", async () => {
+    agentCommand.mockResolvedValueOnce({
+      payloads: [{ text: "hello" }],
+    } as never);
+
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await postChatCompletions(port, {
+        model: "clawdbot",
+        messages: [
+          {
+            role: "user",
+            content: [
+              { type: "text", text: "hello" },
+              { type: "input_text", text: "world" },
+            ],
+          },
+        ],
+      });
+      expect(res.status).toBe(200);
+
+      const [opts] = agentCommand.mock.calls[0] ?? [];
+      expect((opts as { message?: string } | undefined)?.message).toBe(
+        "hello\nworld",
+      );
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("returns a non-streaming OpenAI chat.completion response", async () => {
+    agentCommand.mockResolvedValueOnce({
+      payloads: [{ text: "hello" }],
+    } as never);
+
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await postChatCompletions(port, {
+        stream: false,
+        model: "clawdbot",
+        messages: [{ role: "user", content: "hi" }],
+      });
+      expect(res.status).toBe(200);
+      const json = (await res.json()) as Record<string, unknown>;
+      expect(json.object).toBe("chat.completion");
+      expect(Array.isArray(json.choices)).toBe(true);
+      const choice0 = (json.choices as Array<Record<string, unknown>>)[0] ?? {};
+      const msg =
+        (choice0.message as Record<string, unknown> | undefined) ?? {};
+      expect(msg.role).toBe("assistant");
+      expect(msg.content).toBe("hello");
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("requires a user message", async () => {
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await postChatCompletions(port, {
+        model: "clawdbot",
+        messages: [{ role: "system", content: "yo" }],
+      });
+      expect(res.status).toBe(400);
+      const json = (await res.json()) as Record<string, unknown>;
+      expect((json.error as Record<string, unknown> | undefined)?.type).toBe(
+        "invalid_request_error",
+      );
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("streams SSE chunks when stream=true (delta events)", async () => {
+    agentCommand.mockImplementationOnce(async (opts: unknown) => {
+      const runId = (opts as { runId?: string } | undefined)?.runId ?? "";
+      emitAgentEvent({ runId, stream: "assistant", data: { delta: "he" } });
+      emitAgentEvent({ runId, stream: "assistant", data: { delta: "llo" } });
+      return { payloads: [{ text: "hello" }] } as never;
+    });
+
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await postChatCompletions(port, {
+        stream: true,
+        model: "clawdbot",
+        messages: [{ role: "user", content: "hi" }],
+      });
+      expect(res.status).toBe(200);
+      expect(res.headers.get("content-type") ?? "").toContain(
+        "text/event-stream",
+      );
+
+      const text = await res.text();
+      const data = parseSseDataLines(text);
+      expect(data[data.length - 1]).toBe("[DONE]");
+
+      const jsonChunks = data
+        .filter((d) => d !== "[DONE]")
+        .map((d) => JSON.parse(d) as Record<string, unknown>);
+      expect(jsonChunks.some((c) => c.object === "chat.completion.chunk")).toBe(
+        true,
+      );
+      const allContent = jsonChunks
+        .flatMap(
+          (c) =>
+            (c.choices as Array<Record<string, unknown>> | undefined) ?? [],
+        )
+        .map(
+          (choice) =>
+            (choice.delta as Record<string, unknown> | undefined)?.content,
+        )
+        .filter((v): v is string => typeof v === "string")
+        .join("");
+      expect(allContent).toBe("hello");
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+
+  it("streams SSE chunks when stream=true (fallback when no deltas)", async () => {
+    agentCommand.mockResolvedValueOnce({
+      payloads: [{ text: "hello" }],
+    } as never);
+
+    const port = await getFreePort();
+    const server = await startServer(port);
+    try {
+      const res = await postChatCompletions(port, {
+        stream: true,
+        model: "clawdbot",
+        messages: [{ role: "user", content: "hi" }],
+      });
+      expect(res.status).toBe(200);
+      const text = await res.text();
+      expect(text).toContain("[DONE]");
+      expect(text).toContain("hello");
+    } finally {
+      await server.close({ reason: "test done" });
+    }
+  });
+});
diff --git a/src/gateway/openai-http.ts b/src/gateway/openai-http.ts
new file mode 100644
index 000000000..4194cb33a
--- /dev/null
+++ b/src/gateway/openai-http.ts
@@ -0,0 +1,407 @@
+import { randomUUID } from "node:crypto";
+import type { IncomingMessage, ServerResponse } from "node:http";
+
+import { createDefaultDeps } from "../cli/deps.js";
+import { agentCommand } from "../commands/agent.js";
+import { emitAgentEvent, onAgentEvent } from "../infra/agent-events.js";
+import {
+  buildAgentMainSessionKey,
+  normalizeAgentId,
+} from "../routing/session-key.js";
+import { defaultRuntime } from "../runtime.js";
+import { authorizeGatewayConnect, type ResolvedGatewayAuth } from "./auth.js";
+import { readJsonBody } from "./hooks.js";
+
+type OpenAiHttpOptions = {
+  auth: ResolvedGatewayAuth;
+  maxBodyBytes?: number;
+};
+
+type OpenAiChatMessage = {
+  role?: unknown;
+  content?: unknown;
+};
+
+type OpenAiChatCompletionRequest = {
+  model?: unknown;
+  stream?: unknown;
+  messages?: unknown;
+  user?: unknown;
+};
+
+function sendJson(res: ServerResponse, status: number, body: unknown) {
+  res.statusCode = status;
+  res.setHeader("Content-Type", "application/json; charset=utf-8");
+  res.end(JSON.stringify(body));
+}
+
+function getHeader(req: IncomingMessage, name: string): string | undefined {
+  const raw = req.headers[name.toLowerCase()];
+  if (typeof raw === "string") return raw;
+  if (Array.isArray(raw)) return raw[0];
+  return undefined;
+}
+
+function getBearerToken(req: IncomingMessage): string | undefined {
+  const raw = getHeader(req, "authorization")?.trim() ?? "";
+  if (!raw.toLowerCase().startsWith("bearer ")) return undefined;
+  const token = raw.slice(7).trim();
+  return token || undefined;
+}
+
+function writeSse(res: ServerResponse, data: unknown) {
+  res.write(`data: ${JSON.stringify(data)}\n\n`);
+}
+
+function writeDone(res: ServerResponse) {
+  res.write("data: [DONE]\n\n");
+}
+
+function asMessages(val: unknown): OpenAiChatMessage[] {
+  return Array.isArray(val) ? (val as OpenAiChatMessage[]) : [];
+}
+
+function extractTextContent(content: unknown): string {
+  if (typeof content === "string") return content;
+  if (Array.isArray(content)) {
+    return content
+      .map((part) => {
+        if (!part || typeof part !== "object") return "";
+        const type = (part as { type?: unknown }).type;
+        const text = (part as { text?: unknown }).text;
+        const inputText = (part as { input_text?: unknown }).input_text;
+        if (type === "text" && typeof text === "string") return text;
+        if (type === "input_text" && typeof text === "string") return text;
+        if (typeof inputText === "string") return inputText;
+        return "";
+      })
+      .filter(Boolean)
+      .join("\n");
+  }
+  return "";
+}
+
+function buildAgentPrompt(messagesUnknown: unknown): {
+  message: string;
+  extraSystemPrompt?: string;
+} {
+  const messages = asMessages(messagesUnknown);
+
+  const systemParts: string[] = [];
+  let lastUser = "";
+
+  for (const msg of messages) {
+    if (!msg || typeof msg !== "object") continue;
+    const role = typeof msg.role === "string" ? msg.role.trim() : "";
+    const content = extractTextContent(msg.content).trim();
+    if (!role || !content) continue;
+    if (role === "system") {
+      systemParts.push(content);
+      continue;
+    }
+    if (role === "user") {
+      lastUser = content;
+    }
+  }
+
+  return {
+    message: lastUser,
+    extraSystemPrompt:
+      systemParts.length > 0 ? systemParts.join("\n\n") : undefined,
+  };
+}
+
+function resolveAgentId(req: IncomingMessage): string {
+  const raw =
+    getHeader(req, "x-clawdbot-agent-id")?.trim() ||
+    getHeader(req, "x-clawdbot-agent")?.trim() ||
+    "main";
+  return normalizeAgentId(raw);
+}
+
+function resolveSessionKey(params: {
+  req: IncomingMessage;
+  agentId: string;
+  user?: string | undefined;
+}): string {
+  const explicit = getHeader(params.req, "x-clawdbot-session-key")?.trim();
+  if (explicit) return explicit;
+
+  // Default: stateless per-request session key, but stable if OpenAI "user" is provided.
+  const user = params.user?.trim();
+  const mainKey = user ? `openai-user:${user}` : `openai:${randomUUID()}`;
+  return buildAgentMainSessionKey({ agentId: params.agentId, mainKey });
+}
+
+function coerceRequest(val: unknown): OpenAiChatCompletionRequest {
+  if (!val || typeof val !== "object") return {};
+  return val as OpenAiChatCompletionRequest;
+}
+
+export async function handleOpenAiHttpRequest(
+  req: IncomingMessage,
+  res: ServerResponse,
+  opts: OpenAiHttpOptions,
+): Promise<boolean> {
+  const url = new URL(
+    req.url ?? "/",
+    `http://${req.headers.host || "localhost"}`,
+  );
+  if (url.pathname !== "/v1/chat/completions") return false;
+
+  if (req.method !== "POST") {
+    res.statusCode = 405;
+    res.setHeader("Allow", "POST");
+    res.setHeader("Content-Type", "text/plain; charset=utf-8");
+    res.end("Method Not Allowed");
+    return true;
+  }
+
+  const token = getBearerToken(req);
+  const authResult = await authorizeGatewayConnect({
+    auth: opts.auth,
+    connectAuth: { token, password: token },
+    req,
+  });
+  if (!authResult.ok) {
+    sendJson(res, 401, {
+      error: { message: "Unauthorized", type: "unauthorized" },
+    });
+    return true;
+  }
+
+  const body = await readJsonBody(req, opts.maxBodyBytes ?? 1024 * 1024);
+  if (!body.ok) {
+    sendJson(res, 400, {
+      error: { message: body.error, type: "invalid_request_error" },
+    });
+    return true;
+  }
+
+  const payload = coerceRequest(body.value);
+  const stream = Boolean(payload.stream);
+  const model = typeof payload.model === "string" ? payload.model : "clawdbot";
+  const user = typeof payload.user === "string" ? payload.user : undefined;
+
+  const agentId = resolveAgentId(req);
+  const sessionKey = resolveSessionKey({ req, agentId, user });
+  const prompt = buildAgentPrompt(payload.messages);
+  if (!prompt.message) {
+    sendJson(res, 400, {
+      error: {
+        message: "Missing user message in `messages`.",
+        type: "invalid_request_error",
+      },
+    });
+    return true;
+  }
+
+  const runId = `chatcmpl_${randomUUID()}`;
+  const deps = createDefaultDeps();
+
+  if (!stream) {
+    try {
+      const result = await agentCommand(
+        {
+          message: prompt.message,
+          extraSystemPrompt: prompt.extraSystemPrompt,
+          sessionKey,
+          runId,
+          deliver: false,
+          messageProvider: "webchat",
+          bestEffortDeliver: false,
+        },
+        defaultRuntime,
+        deps,
+      );
+
+      const payloads = (
+        result as { payloads?: Array<{ text?: string }> } | null
+      )?.payloads;
+      const content =
+        Array.isArray(payloads) && payloads.length > 0
+          ? payloads
+              .map((p) => (typeof p.text === "string" ? p.text : ""))
+              .filter(Boolean)
+              .join("\n\n")
+          : "No response from Clawdbot.";
+
+      sendJson(res, 200, {
+        id: runId,
+        object: "chat.completion",
+        created: Math.floor(Date.now() / 1000),
+        model,
+        choices: [
+          {
+            index: 0,
+            message: { role: "assistant", content },
+            finish_reason: "stop",
+          },
+        ],
+        usage: { prompt_tokens: 0, completion_tokens: 0, total_tokens: 0 },
+      });
+    } catch (err) {
+      sendJson(res, 500, {
+        error: { message: String(err), type: "api_error" },
+      });
+    }
+    return true;
+  }
+
+  res.statusCode = 200;
+  res.setHeader("Content-Type", "text/event-stream; charset=utf-8");
+  res.setHeader("Cache-Control", "no-cache");
+  res.setHeader("Connection", "keep-alive");
+  res.flushHeaders?.();
+
+  let wroteRole = false;
+  let sawAssistantDelta = false;
+  let closed = false;
+
+  const unsubscribe = onAgentEvent((evt) => {
+    if (evt.runId !== runId) return;
+    if (closed) return;
+
+    if (evt.stream === "assistant") {
+      const delta = evt.data?.delta;
+      const text = evt.data?.text;
+      const content =
+        typeof delta === "string"
+          ? delta
+          : typeof text === "string"
+            ? text
+            : "";
+      if (!content) return;
+
+      if (!wroteRole) {
+        wroteRole = true;
+        writeSse(res, {
+          id: runId,
+          object: "chat.completion.chunk",
+          created: Math.floor(Date.now() / 1000),
+          model,
+          choices: [{ index: 0, delta: { role: "assistant" } }],
+        });
+      }
+
+      sawAssistantDelta = true;
+      writeSse(res, {
+        id: runId,
+        object: "chat.completion.chunk",
+        created: Math.floor(Date.now() / 1000),
+        model,
+        choices: [
+          {
+            index: 0,
+            delta: { content },
+            finish_reason: null,
+          },
+        ],
+      });
+      return;
+    }
+
+    if (evt.stream === "lifecycle") {
+      const phase = evt.data?.phase;
+      if (phase === "end" || phase === "error") {
+        closed = true;
+        unsubscribe();
+        writeDone(res);
+        res.end();
+      }
+    }
+  });
+
+  req.on("close", () => {
+    closed = true;
+    unsubscribe();
+  });
+
+  void (async () => {
+    try {
+      const result = await agentCommand(
+        {
+          message: prompt.message,
+          extraSystemPrompt: prompt.extraSystemPrompt,
+          sessionKey,
+          runId,
+          deliver: false,
+          messageProvider: "webchat",
+          bestEffortDeliver: false,
+        },
+        defaultRuntime,
+        deps,
+      );
+
+      if (closed) return;
+
+      if (!sawAssistantDelta) {
+        if (!wroteRole) {
+          wroteRole = true;
+          writeSse(res, {
+            id: runId,
+            object: "chat.completion.chunk",
+            created: Math.floor(Date.now() / 1000),
+            model,
+            choices: [{ index: 0, delta: { role: "assistant" } }],
+          });
+        }
+
+        const payloads = (
+          result as { payloads?: Array<{ text?: string }> } | null
+        )?.payloads;
+        const content =
+          Array.isArray(payloads) && payloads.length > 0
+            ? payloads
+                .map((p) => (typeof p.text === "string" ? p.text : ""))
+                .filter(Boolean)
+                .join("\n\n")
+            : "No response from Clawdbot.";
+
+        sawAssistantDelta = true;
+        writeSse(res, {
+          id: runId,
+          object: "chat.completion.chunk",
+          created: Math.floor(Date.now() / 1000),
+          model,
+          choices: [
+            {
+              index: 0,
+              delta: { content },
+              finish_reason: null,
+            },
+          ],
+        });
+      }
+    } catch (err) {
+      if (closed) return;
+      writeSse(res, {
+        id: runId,
+        object: "chat.completion.chunk",
+        created: Math.floor(Date.now() / 1000),
+        model,
+        choices: [
+          {
+            index: 0,
+            delta: { content: `Error: ${String(err)}` },
+            finish_reason: "stop",
+          },
+        ],
+      });
+      emitAgentEvent({
+        runId,
+        stream: "lifecycle",
+        data: { phase: "error" },
+      });
+    } finally {
+      if (!closed) {
+        closed = true;
+        unsubscribe();
+        writeDone(res);
+        res.end();
+      }
+    }
+  })();
+
+  return true;
+}
diff --git a/src/gateway/server-http.ts b/src/gateway/server-http.ts
index 6dc106ac9..dbd4105b1 100644
--- a/src/gateway/server-http.ts
+++ b/src/gateway/server-http.ts
@@ -22,6 +22,7 @@ import {
   resolveHookProvider,
 } from "./hooks.js";
 import { applyHookMappings } from "./hooks-mapping.js";
+import { handleOpenAiHttpRequest } from "./openai-http.js";
 
 type SubsystemLogger = ReturnType<typeof createSubsystemLogger>;
 
@@ -206,12 +207,14 @@ export function createGatewayHttpServer(opts: {
   controlUiEnabled: boolean;
   controlUiBasePath: string;
   handleHooksRequest: HooksRequestHandler;
+  resolvedAuth: import("./auth.js").ResolvedGatewayAuth;
 }): HttpServer {
   const {
     canvasHost,
     controlUiEnabled,
     controlUiBasePath,
     handleHooksRequest,
+    resolvedAuth,
   } = opts;
   const httpServer: HttpServer = createHttpServer((req, res) => {
     // Don't interfere with WebSocket upgrades; ws handles the 'upgrade' event.
@@ -219,6 +222,8 @@ export function createGatewayHttpServer(opts: {
 
     void (async () => {
       if (await handleHooksRequest(req, res)) return;
+      if (await handleOpenAiHttpRequest(req, res, { auth: resolvedAuth }))
+        return;
       if (canvasHost) {
         if (await handleA2uiHttpRequest(req, res)) return;
         if (await canvasHost.handleHttpRequest(req, res)) return;
diff --git a/src/gateway/server.ts b/src/gateway/server.ts
index 2f77446bc..6b51c2065 100644
--- a/src/gateway/server.ts
+++ b/src/gateway/server.ts
@@ -616,6 +616,7 @@ export async function startGatewayServer(
     controlUiEnabled,
     controlUiBasePath,
     handleHooksRequest,
+    resolvedAuth,
   });
   let bonjourStop: (() => Promise<void>) | null = null;
   let bridge: Awaited<ReturnType<typeof startNodeBridgeServer>> | null = null;