Add isolated OpenCode 2 contract shell

package.json

@@ -21,8 +21,8 @@
     "build:plugin": "bun build src/source/v1.js --outfile=src/index.js --target=bun --format=esm --external=@opencode-ai/plugin/tool",
     "build:plugin:npm": "npm install --no-save --package-lock=false bun@1.3.14 && bun build src/source/v1.js --outfile=src/index.js --target=bun --format=esm --external=@opencode-ai/plugin/tool",
     "prepack": "npm run build:plugin:npm && node --check src/index.js",
-    "check": "node --check src/source/v1.js && node --check src/source/core/args.js && node --check src/source/core/state.js && node --check src/source/core/jobs.js && node --check src/source/core/process.js && node --check src/source/opencode/sdk.js && node --check src/source/opencode/session-context.js && node --check src/source/legacy-v1.js && node --check src/index.js && node --check scripts/install-node.mjs && node --check scripts/loopd.mjs && node --check scripts/install-test.mjs && node --check scripts/loopd-test.mjs && node --check scripts/smoke-test.mjs && node --check scripts/comprehensive-watchdog.mjs && node --check scripts/comprehensive-test.mjs && node --check scripts/host-loop-canary.mjs",
-    "test": "node scripts/install-test.mjs && node scripts/loopd-test.mjs && node scripts/smoke-test.mjs && node scripts/comprehensive-watchdog.mjs",
+    "check": "node --check src/source/v1.js && node --check src/source/core/args.js && node --check src/source/core/state.js && node --check src/source/core/jobs.js && node --check src/source/core/process.js && node --check src/source/opencode/sdk.js && node --check src/source/opencode/session-context.js && node --check src/source/opencode2/contract.js && node --check src/source/opencode2/experimental.js && node --check src/source/opencode2/plugin.js && node --check src/source/legacy-v1.js && node --check src/index.js && node --check scripts/install-node.mjs && node --check scripts/loopd.mjs && node --check scripts/install-test.mjs && node --check scripts/loopd-test.mjs && node --check scripts/smoke-test.mjs && node --check scripts/comprehensive-watchdog.mjs && node --check scripts/comprehensive-test.mjs && node --check scripts/opencode2-contract-test.mjs && node --check scripts/host-loop-canary.mjs",
+    "test": "node scripts/opencode2-contract-test.mjs && node scripts/install-test.mjs && node scripts/loopd-test.mjs && node scripts/smoke-test.mjs && node scripts/comprehensive-watchdog.mjs",
     "canary:host": "node scripts/host-loop-canary.mjs",
     "install:global": "node scripts/install-node.mjs",
     "pack:zip": "node scripts/make-zip.mjs"

scripts/opencode2-contract-test.mjs

@@ -0,0 +1,45 @@
+import assert from "node:assert/strict"
+
+import OpenCode2LoopExperimental, { OPENCODE2_PLUGIN_ID } from "../src/source/opencode2/plugin.js"
+import { missingOpenCode2Contract, openCode2Contract } from "../src/source/opencode2/contract.js"
+
+const completeContext = {
+  command: { transform: async () => ({ dispose: async () => {} }) },
+  session: {
+    hook: async () => ({ dispose: async () => {} }),
+    prompt: async () => {},
+  },
+  tool: {
+    transform: async () => ({ dispose: async () => {} }),
+    hook: async () => ({ dispose: async () => {} }),
+  },
+  event: { subscribe: async () => {} },
+}
+
+assert.equal(OPENCODE2_PLUGIN_ID, "bybrawe.opencode-loop.v2")
+assert.equal(OpenCode2LoopExperimental.id, OPENCODE2_PLUGIN_ID)
+assert.deepEqual(openCode2Contract(completeContext), {
+  command: true,
+  session: true,
+  prompt: true,
+  tools: true,
+  toolHooks: true,
+  events: true,
+})
+assert.deepEqual(missingOpenCode2Contract(completeContext), [])
+await OpenCode2LoopExperimental.setup(completeContext)
+
+const incompleteContext = {
+  command: { transform: async () => {} },
+  session: { hook: async () => {} },
+  tool: { transform: async () => {} },
+  event: {},
+}
+
+assert.deepEqual(missingOpenCode2Contract(incompleteContext), ["prompt", "toolHooks", "events"])
+await assert.rejects(
+  () => OpenCode2LoopExperimental.setup(incompleteContext),
+  /V2 host contract unavailable: prompt, toolHooks, events/,
+)
+
+console.log("OpenCode Loop V2 contract test passed")

src/source/opencode2/contract.js

@@ -0,0 +1,16 @@
+export function openCode2Contract(ctx) {
+  return {
+    command: typeof ctx?.command?.transform === "function",
+    session: typeof ctx?.session?.hook === "function",
+    prompt: typeof ctx?.session?.prompt === "function",
+    tools: typeof ctx?.tool?.transform === "function",
+    toolHooks: typeof ctx?.tool?.hook === "function",
+    events: typeof ctx?.event?.subscribe === "function",
+  }
+}
+
+export function missingOpenCode2Contract(ctx) {
+  return Object.entries(openCode2Contract(ctx))
+    .filter(([, available]) => !available)
+    .map(([name]) => name)
+}

src/source/opencode2/experimental.js

@@ -0,0 +1 @@
+export const OPENCODE2_EXPERIMENTAL = true

src/source/opencode2/plugin.js

@@ -0,0 +1,15 @@
+import { missingOpenCode2Contract } from "./contract.js"
+
+export const OPENCODE2_PLUGIN_ID = "bybrawe.opencode-loop.v2"
+
+export const OpenCode2LoopExperimental = {
+  id: OPENCODE2_PLUGIN_ID,
+  setup: async (ctx) => {
+    const missing = missingOpenCode2Contract(ctx)
+    if (missing.length) {
+      throw new Error(`OpenCode Loop V2 host contract unavailable: ${missing.join(", ")}`)
+    }
+  },
+}
+
+export default OpenCode2LoopExperimental