diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
new file mode 100644
index 0000000..aa4d0d9
--- /dev/null
+++ b/.github/workflows/release.yml
@@ -0,0 +1,18 @@
+name: Release
+
+on:
+  push:
+    branches: [main]
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: googleapis/release-please-action@v4
+        with:
+          config-file: .release-please-config.json
+          manifest-file: .release-please-manifest.json
diff --git a/.release-please-config.json b/.release-please-config.json
new file mode 100644
index 0000000..94c1cdd
--- /dev/null
+++ b/.release-please-config.json
@@ -0,0 +1,29 @@
+{
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
+  "packages": {
+    ".": {
+      "release-type": "node",
+      "package-name": "deploygate",
+      "include-component-in-tag": true,
+      "include-v-in-tag": true,
+      "tag-separator": "--",
+      "extra-files": [
+        {
+          "type": "json",
+          "path": "plugin/.claude-plugin/plugin.json",
+          "jsonpath": "$.version"
+        },
+        {
+          "type": "json",
+          "path": "plugin/.codex-plugin/plugin.json",
+          "jsonpath": "$.version"
+        },
+        {
+          "type": "json",
+          "path": ".claude-plugin/marketplace.json",
+          "jsonpath": "$.plugins[0].version"
+        }
+      ]
+    }
+  }
+}
diff --git a/.release-please-manifest.json b/.release-please-manifest.json
new file mode 100644
index 0000000..96f1cd9
--- /dev/null
+++ b/.release-please-manifest.json
@@ -0,0 +1,3 @@
+{
+  ".": "1.3.0"
+}
diff --git a/README.md b/README.md
index 7a53712..f358512 100644
--- a/README.md
+++ b/README.md
@@ -150,6 +150,37 @@ npm run build      # Compile TypeScript + bundle with esbuild
 npm test           # Run tests
 ```
 
+## Releasing
+
+Releases are automated by [release-please](https://github.com/googleapis/release-please).
+
+### Branching and commits
+
+- All work lands on `main` via squash-merged pull requests.
+- PR titles must follow [Conventional Commits](https://www.conventionalcommits.org/):
+  - `feat: …` → minor version bump
+  - `fix: …` → patch version bump
+  - `feat!: …` or a body containing `BREAKING CHANGE: …` → major version bump
+  - `chore:`, `docs:`, `refactor:`, `test:`, `build:`, `ci:` → no version bump (and, by default, do not appear in the changelog unless `changelog-sections` is configured in `.release-please-config.json`)
+- Individual commits inside a PR can have any title; only the squash-merge title matters.
+
+### How a release happens
+
+1. Merge a `feat:` or `fix:` PR into `main`.
+2. The `Release` workflow opens (or updates) a Release PR that bumps the version in `package.json`, both `plugin/.claude-plugin/plugin.json` and `plugin/.codex-plugin/plugin.json`, the `deploygate` entry in `.claude-plugin/marketplace.json`, and `.release-please-manifest.json`, and appends to `CHANGELOG.md`.
+3. Merge the Release PR.
+4. The `Release` workflow runs again, creates the git tag `deploygate--vX.Y.Z`, and publishes a GitHub Release.
+
+### Installing a specific version
+
+End users can pin to a tag with:
+
+```
+/plugin install DeployGate/deploygate-agent-plugin@deploygate--v1.4.0
+```
+
+Without a pin, `claude plugin install` follows `main`. Users can fetch the latest published tag with `claude plugin update deploygate`.
+
 ## Support & Project Status
 
 This plugin is open-source software provided **as-is on a best-effort
diff --git a/src/__tests__/plugin.test.ts b/src/__tests__/plugin.test.ts
index 9f5efd3..2d3df12 100644
--- a/src/__tests__/plugin.test.ts
+++ b/src/__tests__/plugin.test.ts
@@ -187,3 +187,22 @@ describe("plugin/skills/ (slash commands)", () => {
     expect(content).toContain("upload_app");
   });
 });
+
+describe("version sync across release manifests", () => {
+  it("package.json, both plugin.json files, the marketplace entry, and the release-please manifest share the same version", () => {
+    const pkg = loadJson("package.json");
+    const codexPlugin = loadJson("plugin/.codex-plugin/plugin.json");
+    const claudePlugin = loadJson("plugin/.claude-plugin/plugin.json");
+    const marketplace = loadJson(".claude-plugin/marketplace.json");
+    const manifest = loadJson(".release-please-manifest.json");
+
+    const version = pkg.version as string;
+    expect(version).toMatch(/^\d+\.\d+\.\d+$/);
+    expect(codexPlugin.version).toBe(version);
+    expect(claudePlugin.version).toBe(version);
+    const plugins = marketplace.plugins as Array<{ name: string; version: string }>;
+    const deploygateEntry = plugins.find((p) => p.name === "deploygate");
+    expect(deploygateEntry?.version).toBe(version);
+    expect(manifest["."]).toBe(version);
+  });
+});