diff --git a/src/agentex/lib/cli/handlers/deploy_handlers.py b/src/agentex/lib/cli/handlers/deploy_handlers.py
index 605d91709..e1cd1965c 100644
--- a/src/agentex/lib/cli/handlers/deploy_handlers.py
+++ b/src/agentex/lib/cli/handlers/deploy_handlers.py
@@ -389,6 +389,8 @@ def merge_deployment_configs(
             _deep_merge(helm_values, agent_env_config.helm_overrides)
         logger.info(f"After-merge helm values: {helm_values}")
 
+    _stamp_agent_version(helm_values, set(all_env_vars) | {var["name"] for var in secret_env_vars})
+
     # Set final environment variables
     # Environment variable precedence: manifest -> environments.yaml -> secrets (highest)
     if all_env_vars:
@@ -430,6 +432,14 @@ def _deep_merge(base_dict: dict[str, Any], override_dict: dict[str, Any]) -> Non
             base_dict[key] = value
 
 
+def _stamp_agent_version(helm_values: dict[str, Any], declared_env_names: set[str]) -> None:
+    """Set global.agent.version from the merged image tag unless the deployment declares AGENT_VERSION itself."""
+    if EnvVarKeys.AGENT_VERSION.value in declared_env_names:
+        # Chart >=0.6.0 renders global.agent.version as a second AGENT_VERSION env entry.
+        return
+    helm_values["global"]["agent"].setdefault("version", helm_values["global"]["image"]["tag"])
+
+
 def create_helm_values_file(helm_values: dict[str, Any]) -> str:
     """Create a temporary helm values file"""
     with tempfile.NamedTemporaryFile(mode="w", suffix=".yaml", delete=False) as f:
diff --git a/tests/lib/cli/test_deploy_handlers.py b/tests/lib/cli/test_deploy_handlers.py
new file mode 100644
index 000000000..835b56ae8
--- /dev/null
+++ b/tests/lib/cli/test_deploy_handlers.py
@@ -0,0 +1,64 @@
+"""Tests for the helm values merge_deployment_configs assembles for `agentex agents deploy`."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from agentex.config.agent_config import AgentConfig
+from agentex.config.build_config import BuildConfig, BuildContext
+from agentex.config.agent_manifest import AgentManifest
+from agentex.config.deployment_config import ImageConfig, DeploymentConfig
+from agentex.config.environment_config import AgentAuthConfig, AgentEnvironmentConfig
+from agentex.lib.cli.handlers.deploy_handlers import InputDeployOverrides, merge_deployment_configs
+
+MANIFEST_TAG = "sha-manifest"
+
+
+def _manifest(env: dict[str, str] | None = None) -> AgentManifest:
+    return AgentManifest(
+        build=BuildConfig(context=BuildContext(root=".", dockerfile="Dockerfile", dockerignore=None)),
+        agent=AgentConfig(name="emu-tax", description="Files emu taxes", acp_type="async", env=env),
+        deployment=DeploymentConfig(image=ImageConfig(repository="registry.example.com/emu-tax", tag=MANIFEST_TAG)),
+    )
+
+
+def _env_config(helm_overrides: dict[str, Any]) -> AgentEnvironmentConfig:
+    return AgentEnvironmentConfig(auth=AgentAuthConfig(principal={"user_id": "u-1"}), helm_overrides=helm_overrides)
+
+
+def _merge(
+    manifest: AgentManifest,
+    env_config: AgentEnvironmentConfig | None = None,
+    image_tag: str | None = None,
+) -> dict[str, Any]:
+    overrides = InputDeployOverrides(image_tag=image_tag)
+    return merge_deployment_configs(manifest, env_config, overrides, "/nonexistent/manifest.yaml")
+
+
+class TestAgentVersion:
+    def test_stamped_from_the_deploy_image_tag(self):
+        values = _merge(_manifest(), image_tag="sha-cli")
+
+        assert values["global"]["agent"]["version"] == "sha-cli"
+
+    def test_follows_an_image_tag_overridden_in_helm_overrides(self):
+        values = _merge(_manifest(), _env_config({"global": {"image": {"tag": "sha-env"}}}))
+
+        assert values["global"]["image"]["tag"] == "sha-env"
+        assert values["global"]["agent"]["version"] == "sha-env"
+
+    def test_explicit_helm_override_of_the_version_wins(self):
+        values = _merge(_manifest(), _env_config({"global": {"agent": {"version": "pinned"}}}))
+
+        assert values["global"]["agent"]["version"] == "pinned"
+
+    def test_skipped_when_the_manifest_env_declares_agent_version(self):
+        values = _merge(_manifest(env={"AGENT_VERSION": "v1.2.3"}))
+
+        assert "version" not in values["global"]["agent"]
+        assert {"name": "AGENT_VERSION", "value": "v1.2.3"} in values["env"]
+
+    def test_skipped_when_the_environment_env_declares_agent_version(self):
+        values = _merge(_manifest(), _env_config({"env": [{"name": "AGENT_VERSION", "value": "v9"}]}))
+
+        assert "version" not in values["global"]["agent"]