diff --git a/docs-internal/registry-parity-worklist.md b/docs-internal/registry-parity-worklist.md
index 237307251f..f588f47acb 100644
--- a/docs-internal/registry-parity-worklist.md
+++ b/docs-internal/registry-parity-worklist.md
@@ -714,6 +714,16 @@ real e2e tests that prove Linux-parity behavior — not smoke tests.
     `2026-07-08T15-17-00-0700-item12-claude-sidecar-build-after-cache-move.log`;
     `2026-07-08T15-19-00-0700-item12-claude-session-after-cache-move.log`.
     Rev: `rxmoulty`.
+  - **opencode — DONE.** Added default core Vitest coverage for real
+    `createSession('opencode')` initialization through the projected
+    `@agentos-software/opencode` agent package. The focused suite proves the
+    sidecar resolves the OpenCode ACP package, initializes the adapter, exposes
+    agent metadata/capabilities/modes, and registers the session through the
+    Agent OS session API. Proof:
+    `2026-07-08T15-36-00-0700-item12-opencode-cc-cache-restored-focused.log`;
+    `2026-07-08T15-36-00-0700-item12-opencode-sidecar-build-focused.log`;
+    `2026-07-08T15-37-00-0700-item12-opencode-real-session-final.log`.
+    Rev: `xtnuomsw`.
 - **Objective:** write real e2e tests proving each behaves like its Linux
  counterpart (jq processes real JSON, sed edits streams, tar round-trips archives,
   gzip round-trips, etc.); agents exercise the real ACP
diff --git a/packages/core/tests/opencode-real-session.test.ts b/packages/core/tests/opencode-real-session.test.ts
new file mode 100644
index 0000000000..c47f4b2cd6
--- /dev/null
+++ b/packages/core/tests/opencode-real-session.test.ts
@@ -0,0 +1,76 @@
+import { resolve } from "node:path";
+import opencode from "@agentos-software/opencode";
+import { describe, expect, test } from "vitest";
+import type { AgentCapabilities, AgentInfo } from "../src/agent-os.js";
+import { AgentOs } from "../src/agent-os.js";
+import {
+	DEFAULT_TEXT_FIXTURE,
+	startLlmock,
+	stopLlmock,
+} from "./helpers/llmock-helper.js";
+import { moduleAccessMounts } from "./helpers/node-modules-mount.js";
+import {
+	createVmOpenCodeHome,
+	createVmWorkspace,
+} from "./helpers/opencode-helper.js";
+
+const MODULE_ACCESS_CWD = resolve(import.meta.dirname, "..");
+
+async function createOpenCodeVm(mockUrl: string): Promise<AgentOs> {
+	return AgentOs.create({
+		loopbackExemptPorts: [Number(new URL(mockUrl).port)],
+		mounts: moduleAccessMounts(MODULE_ACCESS_CWD),
+		software: [opencode],
+	});
+}
+
+describe("real createSession('opencode')", () => {
+	test("initializes the projected OpenCode ACP package inside the VM", async () => {
+		const { mock, url } = await startLlmock([DEFAULT_TEXT_FIXTURE]);
+		const vm = await createOpenCodeVm(url);
+
+		let sessionId: string | undefined;
+		try {
+			const homeDir = await createVmOpenCodeHome(vm, url);
+			const workspaceDir = await createVmWorkspace(vm);
+			sessionId = (
+				await vm.createSession("opencode", {
+					cwd: workspaceDir,
+					env: {
+						HOME: homeDir,
+						ANTHROPIC_API_KEY: "mock-key",
+					},
+				})
+			).sessionId;
+
+			const agentInfo = vm.getSessionAgentInfo(sessionId) as AgentInfo;
+			expect(agentInfo.name).toBe("OpenCode");
+			expect(agentInfo.version).toBeTruthy();
+
+			const capabilities = vm.getSessionCapabilities(
+				sessionId,
+			) as AgentCapabilities;
+			expect(capabilities.promptCapabilities).toMatchObject({
+				embeddedContext: true,
+				image: true,
+			});
+
+			const modes = vm.getSessionModes(sessionId);
+			expect(modes?.currentModeId).toBe("build");
+			expect(modes?.availableModes.map((mode) => mode.id)).toEqual(
+				expect.arrayContaining(["build", "plan"]),
+			);
+
+			expect(vm.listSessions()).toContainEqual({
+				sessionId,
+				agentType: "opencode",
+			});
+		} finally {
+			if (sessionId) {
+				vm.closeSession(sessionId);
+			}
+			await vm.dispose();
+			await stopLlmock(mock);
+		}
+	}, 120_000);
+});