chore(repo): add version-sync pre-commit hook + adapter round-trip tests

- scripts/check-version-sync.sh validates plugin.json's `version` matches
  the marketplace.json plugin entry. Exits 1 on drift.
- .githooks/pre-commit runs the version-sync check whenever either
  manifest is staged. Activate per-clone with
  `git config core.hooksPath .githooks`.
- DEVELOPMENT.md adds the activation step to Clone and Setup.
- OpenCodeAdapter round-trip tests cover fromOAC → toOAC stability for
  subagent + primary agents and verify that no extra fields are
  introduced on a minimal-input round trip.

Vitest: 607/607 passing (was 604).

Author: MomePP

.githooks/pre-commit

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+#
+# Repo-tracked pre-commit hook.
+#
+# Activate once per clone:
+#   git config core.hooksPath .githooks
+#
+# Skip with: git commit --no-verify
+#
+
+set -e
+
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+
+# Only run version-sync when either manifest file is staged.
+if git diff --cached --name-only | grep -qE '(^plugins/claude-code/\.claude-plugin/plugin\.json$|^\.claude-plugin/marketplace\.json$)'; then
+    bash "$REPO_ROOT/scripts/check-version-sync.sh"
+fi

docs/contributing/DEVELOPMENT.md

@@ -37,8 +37,16 @@ cd OpenAgentsControl
 cd evals/framework
 npm install
 cd ../..
+
+# Activate repo-tracked git hooks (one-time, per clone)
+git config core.hooksPath .githooks
 ```
 
+The `.githooks/pre-commit` hook runs `scripts/check-version-sync.sh`
+whenever `plugin.json` or `marketplace.json` is staged, and blocks
+commits where the plugin version drifts between the two manifests.
+Skip with `git commit --no-verify` if you have a reason.
+
 ### Verify Setup
 
 ```bash

packages/compatibility-layer/tests/unit/adapters/OpenCodeAdapter.test.ts

@@ -285,4 +285,93 @@ System prompt body.`;
       expect(adapter.validateConversion(agent).join(" ")).toMatch(/maxSteps/);
     });
   });
+
+  // ============================================================================
+  // ROUND-TRIP
+  // ============================================================================
+
+  describe("round-trip (fromOAC → toOAC)", () => {
+    it("preserves subagent frontmatter through a full round trip", async () => {
+      const original: OpenAgent = {
+        frontmatter: {
+          name: "code-reviewer",
+          description: "reviews code",
+          mode: "subagent",
+          model: "opus",
+          temperature: 0.2,
+          permission: { edit: "deny", bash: "deny", webfetch: "deny" },
+          skills: ["code-review", "verification-before-completion"],
+        } as AgentFrontmatter,
+        metadata: { name: "code-reviewer" },
+        systemPrompt: "Review code carefully.",
+        contexts: [],
+      };
+
+      const converted = await adapter.fromOAC(original);
+      const agentMd = converted.configs.find((c) => c.fileName.endsWith(".md"))!;
+      const reparsed = await adapter.toOAC(agentMd.content);
+
+      expect(reparsed.frontmatter.name).toBe(original.frontmatter.name);
+      expect(reparsed.frontmatter.description).toBe(original.frontmatter.description);
+      expect(reparsed.frontmatter.mode).toBe(original.frontmatter.mode);
+      expect(reparsed.frontmatter.model).toBe(original.frontmatter.model);
+      expect(reparsed.frontmatter.temperature).toBe(original.frontmatter.temperature);
+      expect(reparsed.frontmatter.permission).toEqual(original.frontmatter.permission);
+      expect(reparsed.frontmatter.skills).toEqual(original.frontmatter.skills);
+      expect(reparsed.systemPrompt).toBe(original.systemPrompt);
+    });
+
+    it("preserves primary agent identity through a round trip (mode + name)", async () => {
+      const original: OpenAgent = {
+        frontmatter: {
+          name: "main",
+          description: "primary loop",
+          mode: "primary",
+          model: "sonnet",
+          tools: { read: true, write: true, edit: true, bash: false },
+        } as AgentFrontmatter,
+        metadata: { name: "main" },
+        systemPrompt: "Primary loop body.",
+        contexts: [],
+      };
+
+      const converted = await adapter.fromOAC(original);
+      const agentMd = converted.configs.find((c) =>
+        c.fileName === ".opencode/agents/main.md"
+      )!;
+      const reparsed = await adapter.toOAC(agentMd.content);
+
+      expect(reparsed.frontmatter.name).toBe("main");
+      expect(reparsed.frontmatter.mode).toBe("primary");
+      expect(reparsed.frontmatter.model).toBe("sonnet");
+      // tools→permission fallback materialised as a permission block in the MD,
+      // and toOAC parses it back as permission (not tools) — assert that lift.
+      expect(reparsed.frontmatter.permission).toBeDefined();
+      expect(reparsed.frontmatter.permission!.edit).toBe("allow");
+      expect(reparsed.frontmatter.permission!.bash).toBe("deny");
+      expect(reparsed.systemPrompt).toBe("Primary loop body.");
+    });
+
+    it("does not introduce extra fields on round trip", async () => {
+      const original: OpenAgent = {
+        frontmatter: {
+          name: "minimal",
+          description: "no extras",
+          mode: "subagent",
+        } as AgentFrontmatter,
+        metadata: { name: "minimal" },
+        systemPrompt: "Body.",
+        contexts: [],
+      };
+
+      const converted = await adapter.fromOAC(original);
+      const agentMd = converted.configs.find((c) => c.fileName.endsWith(".md"))!;
+      const reparsed = await adapter.toOAC(agentMd.content);
+
+      // Optional fields should remain undefined (not coerced to empty objects/arrays).
+      expect(reparsed.frontmatter.temperature).toBeUndefined();
+      expect(reparsed.frontmatter.permission).toBeUndefined();
+      expect(reparsed.frontmatter.skills).toBeUndefined();
+    });
+  });
 });

scripts/check-version-sync.sh

@@ -0,0 +1,82 @@
+#!/usr/bin/env bash
+#
+# check-version-sync.sh
+#
+# Verifies the plugin version is consistent across:
+#   - plugins/claude-code/.claude-plugin/plugin.json   (top-level "version")
+#   - .claude-plugin/marketplace.json                  (plugins[].version where name == "oac")
+#
+# Exits non-zero on mismatch so a pre-commit hook can block the commit.
+#
+# Usage:
+#   bash scripts/check-version-sync.sh
+
+set -e
+
+REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
+PLUGIN_JSON="$REPO_ROOT/plugins/claude-code/.claude-plugin/plugin.json"
+MARKETPLACE_JSON="$REPO_ROOT/.claude-plugin/marketplace.json"
+
+if [ ! -f "$PLUGIN_JSON" ]; then
+    echo "version-sync: $PLUGIN_JSON not found — skipping"
+    exit 0
+fi
+
+if [ ! -f "$MARKETPLACE_JSON" ]; then
+    echo "version-sync: $MARKETPLACE_JSON not found — skipping"
+    exit 0
+fi
+
+# Prefer node (already a project dependency); fall back to python3 or jq.
+read_version() {
+    local file="$1"
+    local jq_filter="$2"
+    local node_filter="$3"
+
+    if command -v node >/dev/null 2>&1; then
+        node -e "
+            const m = require('$file');
+            const v = $node_filter;
+            if (!v) process.exit(2);
+            console.log(v);
+        "
+    elif command -v jq >/dev/null 2>&1; then
+        jq -er "$jq_filter" "$file"
+    elif command -v python3 >/dev/null 2>&1; then
+        python3 - <<PY
+import json, sys
+with open("$file") as f:
+    data = json.load(f)
+$node_filter
+PY
+    else
+        echo "version-sync: need node, jq, or python3 — none found" >&2
+        exit 2
+    fi
+}
+
+PLUGIN_VERSION=$(node -e "
+    const m = require('$PLUGIN_JSON');
+    if (!m.version) process.exit(2);
+    console.log(m.version);
+") || { echo "version-sync: failed to read plugin.json version" >&2; exit 2; }
+
+MARKETPLACE_VERSION=$(node -e "
+    const m = require('$MARKETPLACE_JSON');
+    const oac = (m.plugins || []).find(p => p.name === 'oac');
+    if (!oac || !oac.version) process.exit(2);
+    console.log(oac.version);
+") || { echo "version-sync: failed to read marketplace.json oac version" >&2; exit 2; }
+
+if [ "$PLUGIN_VERSION" != "$MARKETPLACE_VERSION" ]; then
+    echo
+    echo "✗ version-sync: plugin version drift" >&2
+    echo "  plugins/claude-code/.claude-plugin/plugin.json    → $PLUGIN_VERSION" >&2
+    echo "  .claude-plugin/marketplace.json (oac entry)       → $MARKETPLACE_VERSION" >&2
+    echo
+    echo "Bump both files together. Run with --no-verify only if you know why." >&2
+    echo
+    exit 1
+fi
+
+echo "version-sync: $PLUGIN_VERSION (plugin.json) == $MARKETPLACE_VERSION (marketplace.json) ✓"