diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a90006f0f..ca11ea73e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -87,6 +87,14 @@ pnpm dev:coder-acp-copilot        # A single worker natively (pnpm dev:<service-
 pnpm open:portal                  # Open the portal in your browser
 ```
 
+The first Docker start compiles the Rust AI gateway inside its development
+container and can take several minutes. During development, the gateway may use
+all CPUs assigned to Docker or the Podman VM, while its memory remains limited
+to 2 GiB. Keep the Compose command running until the `coder-acp-copilot` logs
+show that it connected to MongoDB and ensured `queue-coder-acp-copilot`; runs
+submitted before that worker is ready remain pending. Later starts reuse the
+gateway's named Cargo target volume and are faster.
+
 ### Debug the Docker development API
 
 `pnpm docker:dev:portal` starts the API with the Node inspector enabled. To
diff --git a/docker-compose.dev.yml b/docker-compose.dev.yml
index 50410ab84..0ac906094 100644
--- a/docker-compose.dev.yml
+++ b/docker-compose.dev.yml
@@ -245,10 +245,11 @@ services:
     build:
       target: dev
     # The dev stage compiles the Rust gateway in-container via `cargo watch`.
-    # A cold `cargo build` peaks well above the prod 512m runtime cap and would
-    # thrash/OOM at that limit (rustc stalls near the cap at ~2% CPU), so give it
-    # headroom — mirrors the 1g dev bump the other in-container-compiled services
-    # (api, judge, portal, ...) already get.
+    # Do not inherit the production 0.5 CPU / 512m runtime caps: a cold build can
+    # otherwise outlive the health window and prevent dependent workers from
+    # starting. Let rustc use all CPUs assigned to the container runtime or
+    # Podman VM while keeping memory bounded.
+    cpus: !reset null
     mem_limit: 2g
     # Persist the cargo `target/` cache in a named volume so the cold build only
     # happens once and survives container recreation. Re-declare the base
@@ -256,12 +257,11 @@ services:
     volumes:
       - gateway_cert:/certs
       - gateway_target:/build/target
-    # A cold cargo build takes several minutes on the very first run (empty cache,
-    # throttled to the base `cpus: 0.5`); the base `start_period: 120s` is enough
-    # once the target/ cache volume is populated but not on a fresh volume. Bump
-    # it for the dev profile only.
+    # A cold cargo build takes several minutes on the first run with an empty
+    # target cache. Keep a generous dev-only grace period for slower machines;
+    # subsequent starts reuse the named target volume and become healthy sooner.
     healthcheck:
-      start_period: 360s
+      start_period: 600s
     develop:
       watch:
         - action: sync
diff --git a/docs/architecture/ai-gateway.md b/docs/architecture/ai-gateway.md
index 772812ef6..65cad747f 100644
--- a/docs/architecture/ai-gateway.md
+++ b/docs/architecture/ai-gateway.md
@@ -466,9 +466,18 @@ gateway:
   healthcheck:
     test: ["CMD", "wget", "-q", "--spider", "http://localhost:18000/health"]
     interval: 5s
-    retries: 10
+    retries: 12
 ```
 
+The development override compiles the gateway under `cargo watch`, persists
+`/build/target` in the `gateway_target` named volume, removes the production CPU
+quota so compilation may use all CPUs assigned to the container runtime or
+Podman VM, and raises the memory limit to 2 GiB. Its health check has a
+600-second first-start grace period so a cold Cargo build cannot cause Compose
+to abandon dependent workers. The Copilot worker waits for the gateway to
+become healthy; until the worker connects to `queue-coder-acp-copilot`,
+submitted runs remain pending.
+
 Workers connect via `HTTP_PROXY=http://<sessionId>@gateway:18000` (session ID embedded as userinfo) and `DEV_PROXY_API_URL=http://gateway:18000`.
 
 ## Kubernetes Deployment
diff --git a/scripts/docker-compose.test.ts b/scripts/docker-compose.test.ts
new file mode 100644
index 000000000..096b29c5f
--- /dev/null
+++ b/scripts/docker-compose.test.ts
@@ -0,0 +1,80 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+import { spawnSync } from "node:child_process";
+import { describe, expect, it } from "vitest";
+
+interface ComposeService {
+  cpus?: number;
+  depends_on?: Record<string, { condition: string }>;
+  healthcheck?: {
+    test?: string[];
+    start_period?: string;
+  };
+  mem_limit?: string;
+  volumes?: Array<{
+    source?: string;
+    target: string;
+  }>;
+}
+
+interface ComposeConfig {
+  services: Record<string, ComposeService>;
+}
+
+// Keep the default unit suite runnable without Docker while preserving strict
+// merged-configuration validation whenever Compose is available.
+const dockerComposeAvailable =
+  spawnSync("docker", ["compose", "version"], {
+    encoding: "utf8",
+  }).status === 0;
+
+describe("development Docker Compose configuration", () => {
+  it.skipIf(!dockerComposeAvailable)(
+    "keeps the gateway cold-build resources and Copilot worker dependency",
+    () => {
+      const result = spawnSync(
+        "docker",
+        [
+          "compose",
+          "-f",
+          "docker-compose.yml",
+          "-f",
+          "docker-compose.dev.yml",
+          "--profile",
+          "copilot",
+          "config",
+          "--format",
+          "json",
+        ],
+        {
+          encoding: "utf8",
+          env: { ...process.env, GITHUB_TOKEN: process.env.GITHUB_TOKEN ?? "" },
+        },
+      );
+
+      expect(result.status, result.stderr).toBe(0);
+
+      const config = JSON.parse(result.stdout) as ComposeConfig;
+      const gateway = config.services.gateway;
+      const copilotWorker = config.services["coder-acp-copilot"];
+
+      expect(gateway.cpus).toBeUndefined();
+      expect(gateway.mem_limit).toBe(String(2 * 1024 ** 3));
+      expect(gateway.healthcheck?.start_period).toBe("10m0s");
+      expect(gateway.healthcheck?.test).toEqual([
+        "CMD-SHELL",
+        "wget -qO- http://127.0.0.1:18000/health || exit 1",
+      ]);
+      expect(gateway.volumes).toContainEqual(
+        expect.objectContaining({
+          source: "gateway_target",
+          target: "/build/target",
+        }),
+      );
+      expect(copilotWorker.depends_on?.gateway?.condition).toBe(
+        "service_healthy",
+      );
+    },
+  );
+});
diff --git a/website/src/styles/contributions.css b/website/src/styles/contributions.css
index 6aa468603..98f3bd382 100644
--- a/website/src/styles/contributions.css
+++ b/website/src/styles/contributions.css
@@ -1,7 +1,9 @@
 /*
  * Copyright (c) Microsoft Corporation.
  * Licensed under the MIT License.
- *
+ */
+
+/*
  * Shared presentation for website contribution data: status messages,
  * count pills, cards, and development-only sample labels.
  */
diff --git a/website/src/styles/contributors.css b/website/src/styles/contributors.css
index 5e75ab0ed..03ef9015a 100644
--- a/website/src/styles/contributors.css
+++ b/website/src/styles/contributors.css
@@ -1,7 +1,9 @@
 /*
  * Copyright (c) Microsoft Corporation.
  * Licensed under the MIT License.
- *
+ */
+
+/*
  * Contributors (<scope-contributors>). An avatar wall on the
  * landing page and a card grid on the Community > Contribute page. Shares
  * the card, message and sample-tag styles in contributions.css.