diff --git a/.env.example b/.env.example
index 6270c7f..e57694b 100644
--- a/.env.example
+++ b/.env.example
@@ -43,15 +43,24 @@ REDIS_URL="redis://:CHANGE_ME@192.168.68.102:6379/11"
 # WORKER_REPO_ROOT=  # defaults to monorepo root (pnpm-workspace.yaml walk-up)
 # WORKER_WORKTREE_BASE=/tmp/echodo-worker-worktrees
 #
-# Phase B — OpenHands agent-server (optional; requires --profile agent-server)
-# WORKER_SESSION_TYPE=minimal          # set to `openhands` when agent-server is running
+# Phase B — coding harness (optional)
+# Preferred: OpenCode (COMPOSE_PROFILES=opencode)
+# WORKER_SESSION_TYPE=minimal          # set to `opencode` when opencode profile is running
+# OPENCODE_SERVER_URL=http://opencode:4096
+# OPENCODE_SERVER_PASSWORD=            # openssl rand -hex 24; must match container
+# OPENCODE_SERVER_USERNAME=opencode
+# OPENCODE_PROVIDER_ID=omniroute
+# WORKER_OPENCODE_WORKSPACE=/workspace/repo
+# OMNIROUTE_BASE_URL=https://omniroute.stillwell.cloud/v1
+# OMNIROUTE_API_KEY=
+# OMNIROUTE_MODEL=auto/coding
+#
+# Legacy: OpenHands agent-server (COMPOSE_PROFILES=agent-server)
+# WORKER_SESSION_TYPE=openhands
 # AGENT_SERVER_URL=http://agent-server:8001
 # WORKER_OPENHANDS_WORKSPACE=/workspace/repo
 # SESSION_API_KEY=                     # must match LOCAL_BACKEND_API_KEY on agent-server
 # LOCAL_BACKEND_API_KEY=               # generate: openssl rand -hex 32
-# OMNIROUTE_BASE_URL=https://omniroute.stillwell.cloud/v1
-# OMNIROUTE_API_KEY=
-# OMNIROUTE_MODEL=auto/coding
 
 # ----- Auth (NextAuth v5) -----
 # Local: http://localhost:3000  •  Prod: https://echodo.stillwell.cloud
diff --git a/apps/worker/package.json b/apps/worker/package.json
index 9b91de6..e5e1197 100644
--- a/apps/worker/package.json
+++ b/apps/worker/package.json
@@ -18,6 +18,7 @@
     "ai": "^4.3.16",
     "drizzle-orm": "^0.38.0",
     "ioredis": "^5.4.2",
+    "yaml": "^2.7.0",
     "zod": "^3.24.0"
   },
   "devDependencies": {
diff --git a/apps/worker/src/env.ts b/apps/worker/src/env.ts
index 7c8c5cd..3b7e254 100644
--- a/apps/worker/src/env.ts
+++ b/apps/worker/src/env.ts
@@ -33,9 +33,14 @@ const envSchema = z.object({
     .string()
     .optional()
     .transform((value) => value?.trim() || "/tmp/echodo-worker-worktrees"),
-  /** Session type: "minimal" (default, in-process) or "openhands" (agent-server). */
+  /**
+   * Session type:
+   * - minimal (default) — in-process tool loop
+   * - opencode — headless `opencode serve` on CT 116 (preferred harness)
+   * - openhands — legacy agent-server (optional profile; not the target path)
+   */
   WORKER_SESSION_TYPE: z
-    .enum(["minimal", "openhands"])
+    .enum(["minimal", "opencode", "openhands"])
     .optional()
     .default("minimal"),
   /** OpenHands agent-server URL. Docker: http://agent-server:8001, Local: http://localhost:18000 */
@@ -53,6 +58,30 @@ const envSchema = z.object({
     .string()
     .optional()
     .transform((value) => value?.trim() || ""),
+  /** OpenCode serve/web base URL. Docker: http://opencode:4096 */
+  OPENCODE_SERVER_URL: z
+    .string()
+    .optional()
+    .transform((value) => value?.trim() || "http://opencode:4096"),
+  /** Must match OPENCODE_SERVER_PASSWORD on the opencode container when set. */
+  OPENCODE_SERVER_PASSWORD: z
+    .string()
+    .optional()
+    .transform((value) => value?.trim() || ""),
+  OPENCODE_SERVER_USERNAME: z
+    .string()
+    .optional()
+    .transform((value) => value?.trim() || "opencode"),
+  /** Provider id registered by @omniroute/opencode-plugin (default omniroute). */
+  OPENCODE_PROVIDER_ID: z
+    .string()
+    .optional()
+    .transform((value) => value?.trim() || "omniroute"),
+  /** Workspace path OpenCode should treat as the project root (shared volume). */
+  WORKER_OPENCODE_WORKSPACE: z
+    .string()
+    .optional()
+    .transform((value) => value?.trim() || "/workspace/repo"),
 });
 
 export type WorkerEnv = z.infer<typeof envSchema>;
diff --git a/apps/worker/src/executor/index.ts b/apps/worker/src/executor/index.ts
index 6ed0c7b..153e4d8 100644
--- a/apps/worker/src/executor/index.ts
+++ b/apps/worker/src/executor/index.ts
@@ -5,6 +5,7 @@ import type {
   WorkerJobContext,
 } from "@tasks/shared/worker";
 import { createMinimalSession } from "../session/minimal-session.js";
+import { createOpenCodeSession, type OpenCodeConfig } from "../session/opencode-session.js";
 import { createOpenHandsSession, type OpenHandsConfig } from "../session/openhands-session.js";
 import { createRemoteAgUiExecutor } from "./remote-ag-ui.js";
 
@@ -82,6 +83,33 @@ function buildOpenHandsExecutor(config: OpenHandsConfig): WorkerExecutor {
   };
 }
 
+function buildOpenCodeExecutor(config: OpenCodeConfig): WorkerExecutor {
+  return {
+    id: "opencode",
+    harnessType: "minimal" as HarnessType,
+    async run(ctx: WorkerJobContext, opts: WorkerExecutorOptions): Promise<{ summary: string; toolCalls: number; tokensTotal?: number; outcome?: "succeeded" | "failed" }> {
+      const session = await createOpenCodeSession(ctx, {
+        config,
+        resolvedModel: opts.resolvedModel as never,
+        roleId: ctx.roleId,
+        briefId: ctx.briefId,
+        briefTitle: opts.convoyTitle,
+        workflowPrompt: opts.workflowPrompt,
+        briefAcceptance: opts.briefAcceptance,
+        briefFiles: opts.briefFiles,
+        maxSteps: opts.maxSteps,
+      });
+      const convoyTitle = opts.convoyTitle ?? "unknown";
+      const result = await session.run(opts.buildPrompt(ctx, convoyTitle));
+      return {
+        summary: result.summary,
+        toolCalls: result.toolCalls,
+        tokensTotal: result.tokensTotal,
+      };
+    },
+  };
+}
+
 export type HarnessExecutorConfig = {
   harnessType: HarnessType;
   endpointUrl?: string | null;
@@ -117,3 +145,15 @@ export function createOpenHandsExecutor(
   }
   return buildOpenHandsExecutor({ agentServerUrl, sessionApiKey, repoRoot });
 }
+
+/**
+ * Create an executor for headless OpenCode (`opencode serve`).
+ * Password is optional (local/dev); production should set OPENCODE_SERVER_PASSWORD.
+ */
+export function createOpenCodeExecutor(config: OpenCodeConfig): WorkerExecutor | null {
+  if (!config.serverUrl) {
+    console.warn("[worker] OpenCode executor unavailable: missing OPENCODE_SERVER_URL");
+    return null;
+  }
+  return buildOpenCodeExecutor(config);
+}
diff --git a/apps/worker/src/executor/opencode-executor.test.ts b/apps/worker/src/executor/opencode-executor.test.ts
new file mode 100644
index 0000000..8bd81a0
--- /dev/null
+++ b/apps/worker/src/executor/opencode-executor.test.ts
@@ -0,0 +1,93 @@
+import { describe, expect, it, vi } from "vitest";
+
+import { createOpenCodeExecutor } from "./index.js";
+
+describe("createOpenCodeExecutor", () => {
+  it("returns null when serverUrl is empty", () => {
+    const exec = createOpenCodeExecutor({
+      serverUrl: "",
+      serverPassword: "",
+      serverUsername: "opencode",
+      repoRoot: "/workspace/repo",
+      providerId: "omniroute",
+    });
+    expect(exec).toBeNull();
+  });
+
+  it("returns an opencode executor with the expected id", () => {
+    const exec = createOpenCodeExecutor({
+      serverUrl: "http://opencode:4096",
+      serverPassword: "secret",
+      serverUsername: "opencode",
+      repoRoot: "/workspace/repo",
+      providerId: "omniroute",
+    });
+    expect(exec).not.toBeNull();
+    expect(exec?.id).toBe("opencode");
+  });
+
+  it("creates a session and posts a message with basic auth", async () => {
+    const fetchImpl = vi
+      .fn()
+      .mockResolvedValueOnce(
+        new Response(JSON.stringify({ id: "ses_1" }), { status: 200 }),
+      )
+      .mockResolvedValueOnce(
+        new Response(
+          JSON.stringify({
+            info: { role: "assistant" },
+            parts: [{ type: "text", text: "done" }, { type: "tool", tool: "bash" }],
+          }),
+          { status: 200 },
+        ),
+      );
+
+    vi.stubGlobal("fetch", fetchImpl);
+
+    const exec = createOpenCodeExecutor({
+      serverUrl: "http://opencode:4096",
+      serverPassword: "secret",
+      serverUsername: "opencode",
+      repoRoot: "/workspace/repo",
+      providerId: "omniroute",
+    });
+    expect(exec).not.toBeNull();
+    if (!exec) return;
+
+    const result = await exec.run(
+      {
+        workspaceId: "w",
+        convoyId: "c",
+        roleId: "role-implementer",
+        briefId: "b",
+        repoRoot: "/workspace/repo",
+      },
+      {
+        resolvedModel: {
+          modelId: "omniroute/auto/coding",
+          providerType: "openai",
+          alias: "auto/coding",
+        },
+        resolvedAlias: "auto/coding",
+        rolePromptPath: "/tmp/role.md",
+        maxSteps: 5,
+        buildPrompt: () => "Implement the thing",
+        convoyTitle: "test",
+      },
+    );
+
+    expect(result.summary).toBe("done");
+    expect(result.toolCalls).toBe(1);
+    expect(fetchImpl).toHaveBeenCalledTimes(2);
+    const [, createInit] = fetchImpl.mock.calls[0]!;
+    expect((createInit as RequestInit).headers).toMatchObject({
+      Authorization: expect.stringMatching(/^Basic /),
+    });
+    const [msgUrl, msgInit] = fetchImpl.mock.calls[1]!;
+    expect(msgUrl).toBe("http://opencode:4096/session/ses_1/message");
+    const body = JSON.parse(String((msgInit as RequestInit).body));
+    expect(body.model).toEqual({ providerID: "omniroute", modelID: "auto/coding" });
+
+    vi.unstubAllGlobals();
+  });
+});
diff --git a/apps/worker/src/handle-job.test.ts b/apps/worker/src/handle-job.test.ts
index b97d7f1..4576f8a 100644
--- a/apps/worker/src/handle-job.test.ts
+++ b/apps/worker/src/handle-job.test.ts
@@ -91,6 +91,11 @@ const env = {
   AGENT_SERVER_URL: "http://agent-server:8001",
   WORKER_OPENHANDS_WORKSPACE: "/workspace/repo",
   SESSION_API_KEY: "",
+  OPENCODE_SERVER_URL: "http://opencode:4096",
+  OPENCODE_SERVER_PASSWORD: "",
+  OPENCODE_SERVER_USERNAME: "opencode",
+  OPENCODE_PROVIDER_ID: "omniroute",
+  WORKER_OPENCODE_WORKSPACE: "/workspace/repo",
   REDIS_URL: "redis://localhost:6379",
 };
 
diff --git a/apps/worker/src/handle-job.ts b/apps/worker/src/handle-job.ts
index 27cf337..d68e52d 100644
--- a/apps/worker/src/handle-job.ts
+++ b/apps/worker/src/handle-job.ts
@@ -30,7 +30,7 @@ import {
 } from "./git/worktree.js";
 import { openDraftPR } from "./git/pr.js";
 import { resolveHarnessForJob, getHarnessExecutor } from "./harness.js";
-import { getExecutor, createOpenHandsExecutor, type HarnessExecutorConfig } from "./executor/index.js";
+import { getExecutor, createOpenCodeExecutor, createOpenHandsExecutor, type HarnessExecutorConfig } from "./executor/index.js";
 import { resolveHarnessForRoleDb } from "./db/harness.js";
 import { resolveRepoRoot } from "./lib/repo-root.js";
 import {
@@ -255,10 +255,31 @@ export async function handleOrchestratorJob(
           }
         : undefined;
 
-    // Resolve the executor from the registry based on the harness type
-    // When WORKER_SESSION_TYPE=openhands, route to OpenHands agent-server executor
+    // Resolve the executor from the registry based on the harness type.
+    // WORKER_SESSION_TYPE=opencode → headless OpenCode (preferred).
+    // WORKER_SESSION_TYPE=openhands → legacy OpenHands agent-server.
     let executor;
-    if (env.WORKER_SESSION_TYPE === "openhands") {
+    if (env.WORKER_SESSION_TYPE === "opencode") {
+      const ocExecutor = createOpenCodeExecutor({
+        serverUrl: env.OPENCODE_SERVER_URL,
+        serverPassword: env.OPENCODE_SERVER_PASSWORD,
+        serverUsername: env.OPENCODE_SERVER_USERNAME,
+        repoRoot: env.WORKER_OPENCODE_WORKSPACE,
+        providerId: env.OPENCODE_PROVIDER_ID,
+      });
+      if (ocExecutor) {
+        executor = ocExecutor;
+        console.info(`[worker] using OpenCode executor server=${env.OPENCODE_SERVER_URL}`);
+      } else {
+        console.warn("[worker] OpenCode executor unavailable, falling back to minimal");
+        const harnessExecutorConfig: HarnessExecutorConfig = {
+          harnessType: harness.harnessType,
+          endpointUrl: harness.endpointUrl,
+          authEnvVar: harness.authEnvVar,
+        };
+        executor = getExecutor(harnessExecutorConfig);
+      }
+    } else if (env.WORKER_SESSION_TYPE === "openhands") {
       const ohExecutor = createOpenHandsExecutor(
         env.AGENT_SERVER_URL,
         env.SESSION_API_KEY,
diff --git a/apps/worker/src/session/opencode-session.ts b/apps/worker/src/session/opencode-session.ts
new file mode 100644
index 0000000..568933f
--- /dev/null
+++ b/apps/worker/src/session/opencode-session.ts
@@ -0,0 +1,175 @@
+import type { ResolvedModel } from "@tasks/shared/model-routing";
+import type { WorkerJobContext, WorkerSession } from "@tasks/shared/worker";
+
+import { buildSkillFullContext, loadAgentSkills } from "./load-skills.js";
+
+/**
+ * Configuration for a headless OpenCode server (`opencode serve` / `opencode web`).
+ * Auth is HTTP basic when OPENCODE_SERVER_PASSWORD is set on the server.
+ */
+export type OpenCodeConfig = {
+  serverUrl: string;
+  /** Basic-auth password; empty = no Authorization header. */
+  serverPassword: string;
+  /** Basic-auth username (OpenCode default: opencode). */
+  serverUsername: string;
+  /** Repo root to scan for .agents/skills/ and to describe in the prompt. */
+  repoRoot: string;
+  /** OpenCode provider id registered by the OmniRoute plugin (default omniroute). */
+  providerId: string;
+};
+
+export type OpenCodeSessionOptions = {
+  config: OpenCodeConfig;
+  resolvedModel: ResolvedModel;
+  roleId: string;
+  briefId?: string;
+  briefTitle?: string;
+  workflowPrompt?: string;
+  briefAcceptance?: string;
+  briefFiles?: string[];
+  maxSteps?: number;
+};
+
+type SessionCreateResponse = { id: string; title?: string };
+type MessageResponse = {
+  info?: { role?: string; error?: { name?: string; message?: string } };
+  parts?: Array<{ type?: string; text?: string; tool?: string }>;
+};
+
+function basicAuthHeader(username: string, password: string): string {
+  const token = Buffer.from(`${username}:${password}`, "utf8").toString("base64");
+  return `Basic ${token}`;
+}
+
+function stripProviderPrefix(modelId: string, providerId: string): string {
+  const prefix = `${providerId}/`;
+  return modelId.startsWith(prefix) ? modelId.slice(prefix.length) : modelId;
+}
+
+/**
+ * Create an OpenCode session that drives a remote `opencode serve` over HTTP.
+ * Prefer this over OpenHands on CT 116 — same OmniRoute catalog via the plugin,
+ * no Docker-in-Docker sandbox, one concurrent agent until RAM upgrade.
+ */
+export async function createOpenCodeSession(
+  context: WorkerJobContext,
+  options: OpenCodeSessionOptions,
+): Promise<WorkerSession> {
+  const {
+    config,
+    resolvedModel,
+    roleId,
+    briefId,
+    briefTitle,
+    workflowPrompt,
+    briefAcceptance,
+    briefFiles,
+  } = options;
+  const apiBase = config.serverUrl.replace(/\/$/, "");
+  const headers: Record<string, string> = {
+    "Content-Type": "application/json",
+    Accept: "application/json",
+  };
+  if (config.serverPassword) {
+    headers.Authorization = basicAuthHeader(config.serverUsername, config.serverPassword);
+  }
+
+  let skillContext = "";
+  try {
+    const skills = await loadAgentSkills(config.repoRoot);
+    skillContext = buildSkillFullContext(skills);
+  } catch (e) {
+    console.warn("[opencode] skill loading failed, continuing without skills:", e);
+  }
+
+  const systemParts: string[] = [
+    `You are an AI agent executing a brief for convoy "${context.convoyId}".`,
+    `Role: ${roleId}`,
+    briefId ? `Brief ID: ${briefId}` : "",
+    briefTitle ? `Brief: ${briefTitle}` : "",
+    `Working directory: ${config.repoRoot}`,
+    workflowPrompt ? `\n## Task\n${workflowPrompt}` : "",
+    briefAcceptance ? `\n## Acceptance criteria\n${briefAcceptance}` : "",
+    briefFiles?.length
+      ? `\n## Files to examine\n${briefFiles.map((f) => `- ${f}`).join("\n")}`
+      : "",
+    skillContext || "",
+    "\n## Instructions\nUse the available tools to inspect and modify the repo. Run lint/type-check when appropriate. Finish with a concise summary of what changed.",
+  ].filter(Boolean);
+  const systemPrompt = systemParts.join("\n");
+
+  const modelId = stripProviderPrefix(resolvedModel.modelId, config.providerId);
+
+  async function createSession(title: string): Promise<string> {
+    const res = await fetch(`${apiBase}/session`, {
+      method: "POST",
+      headers,
+      body: JSON.stringify({ title }),
+    });
+    if (!res.ok) {
+      throw new Error(`OpenCode session create failed (${res.status}): ${await res.text()}`);
+    }
+    const data = (await res.json()) as SessionCreateResponse;
+    if (!data.id) throw new Error("OpenCode session create returned no id");
+    return data.id;
+  }
+
+  async function sendPrompt(sessionId: string, prompt: string): Promise<{
+    summary: string;
+    toolCalls: number;
+  }> {
+    const res = await fetch(`${apiBase}/session/${sessionId}/message`, {
+      method: "POST",
+      headers,
+      body: JSON.stringify({
+        model: { providerID: config.providerId, modelID: modelId },
+        system: systemPrompt,
+        parts: [{ type: "text", text: prompt }],
+      }),
+    });
+    if (!res.ok) {
+      throw new Error(`OpenCode prompt failed (${res.status}): ${await res.text()}`);
+    }
+    const data = (await res.json()) as MessageResponse;
+    if (data.info?.error) {
+      throw new Error(
+        `OpenCode error ${data.info.error.name ?? "unknown"}: ${data.info.error.message ?? ""}`,
+      );
+    }
+    const textParts = (data.parts ?? [])
+      .filter((p) => p.type === "text" && p.text)
+      .map((p) => p.text as string);
+    const toolCalls = (data.parts ?? []).filter((p) => p.type === "tool" || p.tool).length;
+    return {
+      summary: textParts.join("\n").trim() || "OpenCode session completed with no text summary.",
+      toolCalls,
+    };
+  }
+
+  return {
+    context,
+    async run(prompt: string) {
+      console.info(
+        `[opencode] session.run roleId=${roleId} brief=${briefId ?? "none"} model=${config.providerId}/${modelId}`,
+      );
+      try {
+        const title = `convoy:${context.convoyId}:${roleId}:${briefId ?? "none"}`;
+        const sessionId = await createSession(title);
+        console.info(`[opencode] session started id=${sessionId}`);
+        const result = await sendPrompt(sessionId, prompt);
+        console.info(
+          `[opencode] session complete tools=${result.toolCalls} summary_len=${result.summary.length}`,
+        );
+        return result;
+      } catch (e) {
+        const msg = e instanceof Error ? e.message : String(e);
+        console.error(`[opencode] session failed:`, msg);
+        return {
+          summary: `OpenCode session failed: ${msg}`,
+          toolCalls: 0,
+        };
+      }
+    },
+  };
+}
diff --git a/docker/docker-compose.prod.yml b/docker/docker-compose.prod.yml
index de9292f..6f5aa5d 100644
--- a/docker/docker-compose.prod.yml
+++ b/docker/docker-compose.prod.yml
@@ -1,7 +1,9 @@
 # Echodo production stack — shared CT 102 Postgres/Redis, multi-service build.
 #
 # Phase A (default): web, collab, mcp, orchestrator, worker
-# Phase B (optional): OpenHands agent-server — enable with profile `agent-server`
+# Phase B (optional coding harness):
+#   Preferred: OpenCode — COMPOSE_PROFILES=opencode, WORKER_SESSION_TYPE=opencode
+#   Legacy:    OpenHands — COMPOSE_PROFILES=agent-server, WORKER_SESSION_TYPE=openhands
 #
 # Deploy targets:
 #   - Dokploy (CT 112): compose file path `docker/docker-compose.prod.yml`, project dir = repo root
@@ -10,13 +12,18 @@
 # Domains (Dokploy UI or CT 100 Traefik):
 #   web    → echodo.stillwell.cloud        (port 3000)
 #   collab → collab.echodo.stillwell.cloud (port 1234)
+#   opencode (optional) → opencode.stillwell.cloud (port 4096)
 #
 # Build (required on ≤8 GB hosts — parallel export OOMs with exit 255):
 #   bash scripts/build-prod.sh
 # Dokploy → Advanced → Custom Build Command: bash scripts/build-prod.sh
 #
-# Phase B:
-#   docker compose -f docker/docker-compose.prod.yml --profile agent-server up -d
+# Phase B OpenCode:
+#   export COMPOSE_PROFILES=opencode
+#   Set WORKER_SESSION_TYPE=opencode, OPENCODE_SERVER_PASSWORD, OMNIROUTE_API_KEY / BASE_URL.
+#
+# Phase B OpenHands (legacy):
+#   export COMPOSE_PROFILES=agent-server
 #   Set WORKER_SESSION_TYPE=openhands and matching SESSION_API_KEY / LOCAL_BACKEND_API_KEY.
 
 services:
@@ -179,6 +186,11 @@ services:
       - WORKER_OPENHANDS_WORKSPACE=${WORKER_OPENHANDS_WORKSPACE:-/workspace/repo}
       - AGENT_SERVER_URL=${AGENT_SERVER_URL:-http://agent-server:8001}
       - SESSION_API_KEY=${SESSION_API_KEY:-}
+      - OPENCODE_SERVER_URL=${OPENCODE_SERVER_URL:-http://opencode:4096}
+      - OPENCODE_SERVER_PASSWORD=${OPENCODE_SERVER_PASSWORD:-}
+      - OPENCODE_SERVER_USERNAME=${OPENCODE_SERVER_USERNAME:-opencode}
+      - OPENCODE_PROVIDER_ID=${OPENCODE_PROVIDER_ID:-omniroute}
+      - WORKER_OPENCODE_WORKSPACE=${WORKER_OPENCODE_WORKSPACE:-/workspace/repo}
       - OPENAI_API_KEY=${OPENAI_API_KEY}
       - OPENAI_BASE_URL=${OPENAI_BASE_URL}
       - ANTHROPIC_API_KEY=${ANTHROPIC_API_KEY}
@@ -200,6 +212,52 @@ services:
     networks:
       - echodo
 
+  opencode:
+    profiles: ["opencode"]
+    image: ghcr.io/anomalyco/opencode:latest
+    container_name: submatter-opencode
+    restart: unless-stopped
+    working_dir: /workspace/repo
+    entrypoint: ["/bin/sh", "/config/entrypoint.sh"]
+    command:
+      [
+        "opencode",
+        "serve",
+        "--hostname",
+        "0.0.0.0",
+        "--port",
+        "4096",
+      ]
+    environment:
+      - HOME=/data
+      - XDG_CONFIG_HOME=/data/.config
+      - XDG_DATA_HOME=/data/.local/share
+      - OPENCODE_SERVER_PASSWORD=${OPENCODE_SERVER_PASSWORD}
+      - OPENCODE_SERVER_USERNAME=${OPENCODE_SERVER_USERNAME:-opencode}
+      - OMNIROUTE_API_KEY=${OMNIROUTE_API_KEY}
+    volumes:
+      - echodo-workspace:/workspace
+      - opencode-data:/data
+      - ./docker/opencode/opencode.json:/config/opencode.json:ro
+      - ./docker/opencode/entrypoint.sh:/config/entrypoint.sh:ro
+    ports:
+      - "4096:4096"
+    healthcheck:
+      test:
+        - CMD-SHELL
+        - "wget -qO- --timeout=3 http://127.0.0.1:4096/global/health >/dev/null || curl -fsS http://127.0.0.1:4096/global/health >/dev/null || exit 1"
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 45s
+    deploy:
+      resources:
+        limits:
+          memory: 2G
+          cpus: "2"
+    networks:
+      - echodo
+
   agent-server:
     profiles: ["agent-server"]
     image: ghcr.io/open-hands/agent-server:0.19.0
@@ -238,6 +296,7 @@ services:
 
 volumes:
   echodo-workspace:
+  opencode-data:
 
 networks:
   echodo:
diff --git a/docker/opencode/README.md b/docker/opencode/README.md
new file mode 100644
index 0000000..b99719e
--- /dev/null
+++ b/docker/opencode/README.md
@@ -0,0 +1,51 @@
+# OpenCode on CT 116 (Submatter)
+
+Headless coding harness for Submatter. Prefer this over OpenHands.
+
+Runs `opencode serve` on `:4096` (HTTP API for the worker). Attach a TUI with
+`opencode attach http://…:4096`, or use the browser via Traefik once Authentik
+is happy. The image has no desktop browser — do not use `opencode web` in
+compose without an `xdg-open` stub (entrypoint provides one if you switch back).
+
+## Enable
+
+On CT 116 `/opt/submatter/.env`:
+
+```bash
+COMPOSE_PROFILES=opencode
+WORKER_SESSION_TYPE=opencode          # after worker image rebuild with opencode session
+OPENCODE_SERVER_PASSWORD=<openssl rand -hex 24>
+OPENCODE_SERVER_URL=http://opencode:4096
+OMNIROUTE_BASE_URL=https://omniroute.stillwell.cloud/v1
+OMNIROUTE_API_KEY=<gateway inference key>
+```
+
+Then:
+
+```bash
+export COMPOSE_PROFILES=opencode
+bash scripts/deploy-prod.sh up
+# First time / after worker harness code lands:
+# bash scripts/deploy-prod.sh build
+```
+
+Keep `WORKER_SESSION_TYPE=minimal` until the rebuilt worker image includes the
+`opencode` session type (and the `yaml` dependency fix).
+
+## URLs
+
+| Surface | URL |
+|---------|-----|
+| Traefik | `https://opencode.stillwell.cloud` (Authentik + basic auth) |
+| Worker API | `http://opencode:4096` on the `echodo` Docker network |
+| LAN health | `curl -u opencode:$OPENCODE_SERVER_PASSWORD http://192.168.68.116:4096/global/health` |
+
+## Auth
+
+- Browser: Authentik via Traefik (`authentik-auth`) **and** OpenCode basic auth.
+- Worker: same basic auth via `OPENCODE_SERVER_PASSWORD`.
+- Models: `@omniroute/opencode-plugin` + `OMNIROUTE_API_KEY` (seeded into `auth.json` by `entrypoint.sh`).
+
+## RAM
+
+Container capped at 2 GB. Keep one concurrent agent until host RAM → 64 GB.
diff --git a/docker/opencode/entrypoint.sh b/docker/opencode/entrypoint.sh
new file mode 100644
index 0000000..ad6aee3
--- /dev/null
+++ b/docker/opencode/entrypoint.sh
@@ -0,0 +1,27 @@
+#!/bin/sh
+# Seed OmniRoute auth for headless OpenCode, then start serve/web.
+set -eu
+
+CONFIG_HOME="${XDG_CONFIG_HOME:-${HOME:-/data}/.config}"
+DATA_HOME="${XDG_DATA_HOME:-${HOME:-/data}/.local/share}"
+mkdir -p "$CONFIG_HOME/opencode" "$DATA_HOME/opencode" /data/bin
+
+# Container has no desktop — stub xdg-open so `opencode web` does not exit.
+if [ ! -x /data/bin/xdg-open ]; then
+  printf '#!/bin/sh\nexit 0\n' > /data/bin/xdg-open
+  chmod +x /data/bin/xdg-open
+fi
+export PATH="/data/bin:${PATH}"
+
+if [ -f /config/opencode.json ]; then
+  cp /config/opencode.json "$CONFIG_HOME/opencode/opencode.json"
+fi
+
+if [ -n "${OMNIROUTE_API_KEY:-}" ]; then
+  # Keys must not contain double-quotes; OmniRoute keys are hex/base64-safe.
+  printf '{"omniroute":{"type":"api","key":"%s"}}\n' "$OMNIROUTE_API_KEY" \
+    > "$DATA_HOME/opencode/auth.json"
+  chmod 600 "$DATA_HOME/opencode/auth.json" || true
+fi
+
+exec "$@"
diff --git a/docker/opencode/opencode.json b/docker/opencode/opencode.json
new file mode 100644
index 0000000..79f6899
--- /dev/null
+++ b/docker/opencode/opencode.json
@@ -0,0 +1,16 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "plugin": [
+    [
+      "@omniroute/opencode-plugin",
+      {
+        "providerId": "omniroute",
+        "baseURL": "http://192.168.68.108:20128"
+      }
+    ]
+  ],
+  "server": {
+    "port": 4096,
+    "hostname": "0.0.0.0"
+  }
+}
diff --git a/docker/worker-entrypoint.sh b/docker/worker-entrypoint.sh
index 717b2b4..ee439bb 100755
--- a/docker/worker-entrypoint.sh
+++ b/docker/worker-entrypoint.sh
@@ -1,13 +1,18 @@
 #!/bin/sh
 set -eu
 
-# When OpenHands is enabled, seed the shared workspace volume from the deploy
-# snapshot baked into the image (/app/repo). Agent-server reads the same path.
-if [ "${WORKER_SESSION_TYPE:-minimal}" = "openhands" ]; then
-  target="${WORKER_OPENHANDS_WORKSPACE:-/workspace/repo}"
+# When a remote harness shares a workspace volume, seed it from the deploy
+# snapshot baked into the image (/app/repo).
+session_type="${WORKER_SESSION_TYPE:-minimal}"
+if [ "$session_type" = "openhands" ] || [ "$session_type" = "opencode" ]; then
+  if [ "$session_type" = "opencode" ]; then
+    target="${WORKER_OPENCODE_WORKSPACE:-/workspace/repo}"
+  else
+    target="${WORKER_OPENHANDS_WORKSPACE:-/workspace/repo}"
+  fi
   mkdir -p "$(dirname "$target")"
   if [ ! -f "$target/pnpm-workspace.yaml" ]; then
-    echo "[worker-entrypoint] seeding OpenHands workspace at ${target}"
+    echo "[worker-entrypoint] seeding ${session_type} workspace at ${target}"
     mkdir -p "$target"
     cp -a /app/repo/. "$target/"
   fi
diff --git a/docs/deployment-production.md b/docs/deployment-production.md
index dd34e95..d322a5c 100644
--- a/docs/deployment-production.md
+++ b/docs/deployment-production.md
@@ -117,7 +117,26 @@ If Forgejo is canonical git and you want push deploy without Actions:
 
 ---
 
-## Phase B — OpenHands (optional)
+## Phase B — OpenCode (preferred)
+
+```bash
+export COMPOSE_PROFILES=opencode
+# Set in .env: WORKER_SESSION_TYPE=opencode, OPENCODE_SERVER_PASSWORD, OMNIROUTE_*
+bash scripts/deploy-prod.sh build   # first time / worker code change
+# or: bash scripts/deploy-prod.sh up
+```
+
+| Variable | Notes |
+|----------|-------|
+| `OPENCODE_SERVER_PASSWORD` | `openssl rand -hex 24` — Traefik still fronts Authentik |
+| `WORKER_SESSION_TYPE` | `opencode` |
+| `OPENCODE_SERVER_URL` | `http://opencode:4096` (Docker DNS) |
+| `OMNIROUTE_BASE_URL` | `https://omniroute.stillwell.cloud/v1` or LAN `http://192.168.68.108:20128/v1` |
+| `OMNIROUTE_API_KEY` | OmniRoute bearer key |
+
+Web UI: `https://opencode.stillwell.cloud`. Details: `docker/opencode/README.md`.
+
+### Legacy — OpenHands (optional)
 
 ```bash
 export COMPOSE_PROFILES=agent-server
@@ -129,11 +148,8 @@ bash scripts/deploy-prod.sh build
 | `LOCAL_BACKEND_API_KEY` | `openssl rand -hex 32` |
 | `SESSION_API_KEY` | Same as above (worker) |
 | `WORKER_SESSION_TYPE` | `openhands` |
-| `OMNIROUTE_BASE_URL` | `https://omniroute.stillwell.cloud/v1` |
-| `OMNIROUTE_API_KEY` | OmniRoute bearer key |
-
-Requires Docker socket on CT 116 (`nesting=1` on LXC).
 
+Requires Docker socket on CT 116 (`nesting=1` on LXC). Prefer OpenCode unless debugging the old path.
 ---
 
 ## Troubleshooting
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 3b16179..2c7d6d1 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -393,6 +393,9 @@ importers:
       ioredis:
         specifier: ^5.4.2
         version: 5.10.1
+      yaml:
+        specifier: ^2.7.0
+        version: 2.8.3
       zod:
         specifier: ^3.24.0
         version: 3.25.76
diff --git a/proxmox/ct116/README.md b/proxmox/ct116/README.md
index c4c92b1..6cf9b9a 100644
--- a/proxmox/ct116/README.md
+++ b/proxmox/ct116/README.md
@@ -108,7 +108,16 @@ Handler: `deploy-webhook.sh`
 ssh root@192.168.68.116 'cd /opt/submatter && git pull && bash scripts/deploy-prod.sh build'
 ```
 
-## Phase B (OpenHands)
+## Phase B (OpenCode — preferred)
+
+```bash
+export COMPOSE_PROFILES=opencode
+bash scripts/deploy-prod.sh build
+```
+
+Set in `.env`: `WORKER_SESSION_TYPE=opencode`, `OPENCODE_SERVER_PASSWORD`, `OMNIROUTE_API_KEY` / `OMNIROUTE_BASE_URL`. See `docker/opencode/README.md`.
+
+### Legacy Phase B (OpenHands)
 
 ```bash
 export COMPOSE_PROFILES=agent-server
@@ -116,7 +125,6 @@ bash scripts/deploy-prod.sh build
 ```
 
 Set `WORKER_SESSION_TYPE=openhands`, `SESSION_API_KEY`, `LOCAL_BACKEND_API_KEY`, OmniRoute vars in `.env`.
-
 ## AGENT-DEPLOY.md handoff
 
 After CT is live, add to your local `AGENT-DEPLOY.md` (gitignored):