diff --git a/src/agent/README.md b/src/agent/README.md
index f89334d..55877d2 100644
--- a/src/agent/README.md
+++ b/src/agent/README.md
@@ -34,6 +34,15 @@ Agent 不再依赖配置文件；所有参数均由环境变量与主机名推
 | `MASTER_ENDPOINT` | 是 | N/A | Master 基础地址，可写 `http://host:3000` 或 `host:3000`（自动补全 `http://`）。 |
 | `REPORT_INTERVAL_SECONDS` | 否 | `60` | 状态上报间隔（秒）。必须为正整数。 |
 | `AGENT_HOSTNAME` | 否 | `$(hostname)` | 覆盖容器内主机名，便于测试或特殊命名需求。 |
+| `AGENT_ENV` | 否 | 来源于主机名 | 运行环境标识（如 `dev`、`prod`）。与 `AGENT_USER`、`AGENT_INSTANCE` 必须同时设置。 |
+| `AGENT_USER` | 否 | 来源于主机名 | 归属用户或团队标识。与 `AGENT_ENV`、`AGENT_INSTANCE` 必须同时设置。 |
+| `AGENT_INSTANCE` | 否 | 来源于主机名 | 实例编号或别名。与 `AGENT_ENV`、`AGENT_USER` 必须同时设置。 |
+
+主机名与元数据的解析优先级：
+
+1. 若设置 `AGENT_ENV` / `AGENT_USER` / `AGENT_INSTANCE` 且全部存在，则直接使用这些值。
+2. 否则按历史约定从主机名解析 `env-user-instance` 前缀。
+3. 如果两者都无法得到完整结果，Agent 启动会失败并提示需要提供上述环境变量。
 
 派生路径：
 
diff --git a/src/agent/app/collector.py b/src/agent/app/collector.py
index 1b61caa..6c913df 100644
--- a/src/agent/app/collector.py
+++ b/src/agent/app/collector.py
@@ -18,13 +18,12 @@ _HOSTNAME_PATTERN = re.compile(r"^([^-]+)-([^-]+)-([^-]+)-.*$")
 def collect_metadata(config: AgentConfig) -> Dict[str, Any]:
     """汇总节点注册需要的静态信息。"""
     hostname = config.hostname
-    env, user, instance = _parse_hostname(hostname)
     meta = {
         "hostname": hostname,
         "ip": _detect_ip_address(),
-        "env": env,
-        "user": user,
-        "instance": instance,
+        "env": config.environment,
+        "user": config.user,
+        "instance": config.instance,
         "cpu_number": _detect_cpu_count(),
         "memory_in_bytes": _detect_memory_bytes(),
         "gpu_number": _detect_gpu_count(),
diff --git a/src/agent/app/config.py b/src/agent/app/config.py
index dae5d47..bf02cf5 100644
--- a/src/agent/app/config.py
+++ b/src/agent/app/config.py
@@ -14,6 +14,9 @@ DEFAULT_REPORT_INTERVAL_SECONDS: Final[int] = 60
 @dataclass(frozen=True)
 class AgentConfig:
     hostname: str
+    environment: str
+    user: str
+    instance: str
     node_file: str
     version: str
     master_endpoint: str
@@ -47,10 +50,51 @@ def _resolve_hostname() -> str:
     return os.environ.get("AGENT_HOSTNAME") or socket.gethostname()
 
 
+def _resolve_metadata_fields(hostname: str) -> tuple[str, str, str]:
+    env = os.environ.get("AGENT_ENV")
+    user = os.environ.get("AGENT_USER")
+    instance = os.environ.get("AGENT_INSTANCE")
+
+    if env and user and instance:
+        return env, user, instance
+
+    if any([env, user, instance]):
+        LOGGER = None
+        try:
+            from .log import get_logger
+
+            LOGGER = get_logger("argus.agent.config")
+        except Exception:  # pragma: no cover - defensive
+            LOGGER = None
+        if LOGGER is not None:
+            LOGGER.warning(
+                "Incomplete metadata environment variables; falling back to hostname parsing",
+                extra={
+                    "has_env": bool(env),
+                    "has_user": bool(user),
+                    "has_instance": bool(instance),
+                },
+            )
+        env = user = instance = None
+
+    from .collector import _parse_hostname  # Local import to avoid circular dependency
+
+    env, user, instance = _parse_hostname(hostname)
+
+    if not all([env, user, instance]):
+        raise ValueError(
+            "Failed to determine metadata fields; set AGENT_ENV/USER/INSTANCE or use supported hostname pattern"
+        )
+
+    return env, user, instance
+
+
 def load_config() -> AgentConfig:
     """从环境变量推导配置，移除了外部配置文件依赖。"""
 
     hostname = _resolve_hostname()
+    environment, user, instance = _resolve_metadata_fields(hostname)
+
     node_file = f"/private/argus/agent/{hostname}/node.json"
     health_dir = f"/private/argus/agent/{hostname}/health/"
 
@@ -66,6 +110,9 @@ def load_config() -> AgentConfig:
 
     return AgentConfig(
         hostname=hostname,
+        environment=environment,
+        user=user,
+        instance=instance,
         node_file=node_file,
         version=VERSION,
         master_endpoint=master_endpoint,
diff --git a/src/agent/dist/argus-agent b/src/agent/dist/argus-agent
index 4fef67c..d5703fe 100755
Binary files a/src/agent/dist/argus-agent and b/src/agent/dist/argus-agent differ
diff --git a/src/agent/tests/__init__.py b/src/agent/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/agent/tests/docker-compose.yml b/src/agent/tests/docker-compose.yml
index e24e252..0dd4743 100644
--- a/src/agent/tests/docker-compose.yml
+++ b/src/agent/tests/docker-compose.yml
@@ -60,6 +60,36 @@ services:
         ipv4_address: 172.28.0.20
     restart: always
 
+  agent_env:
+    image: ubuntu:22.04
+    container_name: argus-agent-env-e2e
+    hostname: host_abc
+    depends_on:
+      - master
+      - bind
+    environment:
+      - MASTER_ENDPOINT=http://master.argus.com:3000
+      - REPORT_INTERVAL_SECONDS=2
+      - AGENT_ENV=prod
+      - AGENT_USER=ml
+      - AGENT_INSTANCE=node-3
+      - AGENT_HOSTNAME=host_abc
+      - "ARGUS_BUILD_UID=${ARGUS_BUILD_UID:-2133}"
+      - "ARGUS_BUILD_GID=${ARGUS_BUILD_GID:-2015}"
+    volumes:
+      - ./private/argus/agent/host_abc:/private/argus/agent/host_abc
+      - ./private/argus/agent/host_abc/health:/private/argus/agent/host_abc/health
+      - ./private/argus/etc:/private/argus/etc
+      - ../dist/argus-agent:/usr/local/bin/argus-agent:ro
+      - ./scripts/agent_entrypoint.sh:/usr/local/bin/agent-entrypoint.sh:ro
+      - ../scripts/agent_deployment_verify.sh:/usr/local/bin/agent_deployment_verify.sh:ro
+    entrypoint:
+      - /usr/local/bin/agent-entrypoint.sh
+    networks:
+      default:
+        ipv4_address: 172.28.0.21
+    restart: always
+
 networks:
   default:
     driver: bridge
diff --git a/src/agent/tests/scripts/00_e2e_test.sh b/src/agent/tests/scripts/00_e2e_test.sh
index 9515d34..14e27f7 100755
--- a/src/agent/tests/scripts/00_e2e_test.sh
+++ b/src/agent/tests/scripts/00_e2e_test.sh
@@ -7,10 +7,10 @@ SCRIPTS=(
   "02_up.sh"
   "03_wait_and_assert_registration.sh"
   "04_write_health_files.sh"
-  "08_verify_agent.sh"
-  "05_assert_status_on_master.sh"
-  "06_restart_agent_and_reregister.sh"
-  "07_down.sh"
+  "05_verify_agent.sh"
+  "06_assert_status_on_master.sh"
+  "07_restart_agent_and_reregister.sh"
+  "08_down.sh"
 )
 
 for script in "${SCRIPTS[@]}"; do
diff --git a/src/agent/tests/scripts/02_up.sh b/src/agent/tests/scripts/02_up.sh
index 56c4cda..d490a50 100755
--- a/src/agent/tests/scripts/02_up.sh
+++ b/src/agent/tests/scripts/02_up.sh
@@ -41,7 +41,7 @@ compose() {
   fi
 }
 
-docker container rm -f argus-agent-e2e argus-master-agent-e2e argus-bind-agent-e2e >/dev/null 2>&1 || true
+docker container rm -f argus-agent-e2e argus-agent-env-e2e argus-master-agent-e2e argus-bind-agent-e2e >/dev/null 2>&1 || true
 
 docker network rm tests_default >/dev/null 2>&1 || true
 
diff --git a/src/agent/tests/scripts/03_wait_and_assert_registration.sh b/src/agent/tests/scripts/03_wait_and_assert_registration.sh
index 7e9c127..8b0481b 100755
--- a/src/agent/tests/scripts/03_wait_and_assert_registration.sh
+++ b/src/agent/tests/scripts/03_wait_and_assert_registration.sh
@@ -6,11 +6,14 @@ TEST_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
 TMP_ROOT="$TEST_ROOT/tmp"
 API_BASE="http://localhost:32300/api/v1/master"
 AGENT_HOSTNAME="dev-e2euser-e2einst-pod-0"
+ENV_AGENT_HOSTNAME="host_abc"
 NODE_FILE="$TEST_ROOT/private/argus/agent/$AGENT_HOSTNAME/node.json"
+ENV_NODE_FILE="$TEST_ROOT/private/argus/agent/$ENV_AGENT_HOSTNAME/node.json"
 
 mkdir -p "$TMP_ROOT"
 
-node_id=""
+primary_node_id=""
+env_node_id=""
 for _ in {1..30}; do
   sleep 2
   response=$(curl -sS "$API_BASE/nodes" || true)
@@ -19,24 +22,49 @@ for _ in {1..30}; do
   fi
   list_file="$TMP_ROOT/nodes_list.json"
   echo "$response" > "$list_file"
-  node_id=$(python3 - "$list_file" <<'PY'
+  readarray -t node_ids < <(python3 - "$list_file" "$AGENT_HOSTNAME" "$ENV_AGENT_HOSTNAME" <<'PY'
 import json, sys
+
 with open(sys.argv[1]) as handle:
     nodes = json.load(handle)
-print(nodes[0]["id"] if nodes else "")
+
+target_primary = sys.argv[2]
+target_env = sys.argv[3]
+
+primary_id = ""
+env_id = ""
+
+for node in nodes:
+    if node.get("name") == target_primary:
+        primary_id = node.get("id", "")
+    if node.get("name") == target_env:
+        env_id = node.get("id", "")
+
+print(primary_id)
+print(env_id)
 PY
-)
-  if [[ -n "$node_id" ]]; then
+  )
+
+  primary_node_id="${node_ids[0]}"
+  env_node_id="${node_ids[1]}"
+
+  if [[ -n "$primary_node_id" && -n "$env_node_id" ]]; then
     break
   fi
  done
 
-if [[ -z "$node_id" ]]; then
-  echo "[ERROR] Agent did not register within timeout" >&2
+if [[ -z "$primary_node_id" ]]; then
+  echo "[ERROR] Primary agent did not register within timeout" >&2
   exit 1
 fi
 
-echo "$node_id" > "$TMP_ROOT/node_id"
+if [[ -z "$env_node_id" ]]; then
+  echo "[ERROR] Env-variable agent did not register within timeout" >&2
+  exit 1
+fi
+
+echo "$primary_node_id" > "$TMP_ROOT/node_id"
+echo "$env_node_id" > "$TMP_ROOT/node_id_host_abc"
 
 if [[ ! -f "$NODE_FILE" ]]; then
   echo "[ERROR] node.json not created at $NODE_FILE" >&2
@@ -50,8 +78,20 @@ with open(sys.argv[1]) as handle:
 assert "id" in node and node["id"], "node.json missing id"
 PY
 
+if [[ ! -f "$ENV_NODE_FILE" ]]; then
+  echo "[ERROR] node.json not created at $ENV_NODE_FILE" >&2
+  exit 1
+fi
+
+python3 - "$ENV_NODE_FILE" <<'PY'
+import json, sys
+with open(sys.argv[1]) as handle:
+    node = json.load(handle)
+assert "id" in node and node["id"], "env agent node.json missing id"
+PY
+
 detail_file="$TMP_ROOT/initial_detail.json"
-curl -sS "$API_BASE/nodes/$node_id" -o "$detail_file"
+curl -sS "$API_BASE/nodes/$primary_node_id" -o "$detail_file"
 python3 - "$detail_file" "$TMP_ROOT/initial_ip" <<'PY'
 import json, sys, pathlib
 with open(sys.argv[1]) as handle:
@@ -62,4 +102,5 @@ if not ip:
 pathlib.Path(sys.argv[2]).write_text(ip)
 PY
 
-echo "[INFO] Agent registered with node id $node_id"
+echo "[INFO] Agent registered with node id $primary_node_id"
+echo "[INFO] Env-variable agent registered with node id $env_node_id"
diff --git a/src/agent/tests/scripts/05_verify_agent.sh b/src/agent/tests/scripts/05_verify_agent.sh
new file mode 100755
index 0000000..2d4d9b8
--- /dev/null
+++ b/src/agent/tests/scripts/05_verify_agent.sh
@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+TEST_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+REPO_ROOT="$(cd "$TEST_ROOT/.." && pwd)"
+VERIFY_SCRIPT="$REPO_ROOT/scripts/agent_deployment_verify.sh"
+ENV_NODE_ID_FILE="$TEST_ROOT/tmp/node_id_host_abc"
+PRIMARY_CONTAINER="argus-agent-e2e"
+ENV_CONTAINER="argus-agent-env-e2e"
+PRIMARY_HOSTNAME="dev-e2euser-e2einst-pod-0"
+ENV_HOSTNAME="host_abc"
+
+if ! docker ps --format '{{.Names}}' | grep -q "^${PRIMARY_CONTAINER}$"; then
+  echo "[WARN] agent container not running; skip verification"
+  exit 0
+fi
+
+if docker exec -i "$PRIMARY_CONTAINER" bash -lc 'command -v curl >/dev/null && command -v jq >/dev/null'; then
+  echo "[INFO] curl/jq already installed in agent container"
+else
+  echo "[INFO] Installing curl/jq in agent container"
+  docker exec -i "$PRIMARY_CONTAINER" bash -lc 'apt-get update >/dev/null 2>&1 && apt-get install -y curl jq >/dev/null 2>&1' || true
+fi
+
+if [[ ! -f "$VERIFY_SCRIPT" ]]; then
+  echo "[ERROR] Verification script missing at $VERIFY_SCRIPT" >&2
+  exit 1
+fi
+
+run_verifier() {
+  local container="$1" hostname="$2"
+
+  if ! docker ps --format '{{.Names}}' | grep -q "^${container}$"; then
+    echo "[WARN] container $container not running; skip"
+    return
+  fi
+
+  if ! docker exec -i "$container" bash -lc 'command -v /usr/local/bin/agent_deployment_verify.sh >/dev/null'; then
+    echo "[ERROR] /usr/local/bin/agent_deployment_verify.sh missing in $container" >&2
+    exit 1
+  fi
+
+  echo "[INFO] Running verification for $hostname in $container"
+  docker exec -i "$container" env VERIFY_HOSTNAME="$hostname" /usr/local/bin/agent_deployment_verify.sh
+}
+
+run_verifier "$PRIMARY_CONTAINER" "$PRIMARY_HOSTNAME"
+
+if docker ps --format '{{.Names}}' | grep -q "^${ENV_CONTAINER}$"; then
+  if docker exec -i "$ENV_CONTAINER" bash -lc 'command -v curl >/dev/null && command -v jq >/dev/null'; then
+    echo "[INFO] curl/jq already installed in env agent container"
+  else
+    echo "[INFO] Installing curl/jq in env agent container"
+    docker exec -i "$ENV_CONTAINER" bash -lc 'apt-get update >/dev/null 2>&1 && apt-get install -y curl jq >/dev/null 2>&1' || true
+  fi
+  run_verifier "$ENV_CONTAINER" "$ENV_HOSTNAME"
+else
+  echo "[WARN] env-driven agent container not running; skip secondary verification"
+fi
diff --git a/src/agent/tests/scripts/05_assert_status_on_master.sh b/src/agent/tests/scripts/06_assert_status_on_master.sh
similarity index 57%
rename from src/agent/tests/scripts/05_assert_status_on_master.sh
rename to src/agent/tests/scripts/06_assert_status_on_master.sh
index b1b0a87..3c58426 100755
--- a/src/agent/tests/scripts/05_assert_status_on_master.sh
+++ b/src/agent/tests/scripts/06_assert_status_on_master.sh
@@ -6,6 +6,8 @@ TEST_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
 TMP_ROOT="$TEST_ROOT/tmp"
 API_BASE="http://localhost:32300/api/v1/master"
 NODE_ID="$(cat "$TMP_ROOT/node_id")"
+ENV_NODE_ID="$(cat "$TMP_ROOT/node_id_host_abc")"
+ENV_HOSTNAME="host_abc"
 NODES_JSON="$TEST_ROOT/private/argus/metric/prometheus/nodes.json"
 
 success=false
@@ -41,13 +43,36 @@ if [[ ! -f "$NODES_JSON" ]]; then
   exit 1
 fi
 
-python3 - "$NODES_JSON" <<'PY'
+python3 - "$NODES_JSON" "$NODE_ID" "$ENV_NODE_ID" <<'PY'
 import json, sys
 with open(sys.argv[1]) as handle:
     nodes = json.load(handle)
-assert len(nodes) == 1, nodes
-entry = nodes[0]
-assert entry["node_id"], entry
+
+expected_primary = sys.argv[2]
+expected_env = sys.argv[3]
+
+ids = {entry.get("node_id") for entry in nodes}
+assert expected_primary in ids, nodes
+assert expected_env in ids, nodes
+assert len(nodes) >= 2, nodes
 PY
 
 echo "[INFO] Master reflects agent health and nodes.json entries"
+
+env_detail_file="$TMP_ROOT/env_agent_detail.json"
+curl -sS "$API_BASE/nodes/$ENV_NODE_ID" -o "$env_detail_file"
+python3 - "$env_detail_file" "$ENV_HOSTNAME" <<'PY'
+import json, sys
+with open(sys.argv[1]) as handle:
+    node = json.load(handle)
+
+expected_name = sys.argv[2]
+
+assert node.get("name") == expected_name, node
+meta = node.get("meta_data", {})
+assert meta.get("env") == "prod", meta
+assert meta.get("user") == "ml", meta
+assert meta.get("instance") == "node-3", meta
+PY
+
+echo "[INFO] Env-variable agent reports expected metadata"
diff --git a/src/agent/tests/scripts/06_restart_agent_and_reregister.sh b/src/agent/tests/scripts/07_restart_agent_and_reregister.sh
similarity index 94%
rename from src/agent/tests/scripts/06_restart_agent_and_reregister.sh
rename to src/agent/tests/scripts/07_restart_agent_and_reregister.sh
index 78c6322..9fa272e 100755
--- a/src/agent/tests/scripts/06_restart_agent_and_reregister.sh
+++ b/src/agent/tests/scripts/07_restart_agent_and_reregister.sh
@@ -10,6 +10,7 @@ AGENT_HOSTNAME="dev-e2euser-e2einst-pod-0"
 NETWORK_NAME="tests_default"
 NEW_AGENT_IP="172.28.0.200"
 ENTRYPOINT_SCRIPT="$SCRIPT_DIR/agent_entrypoint.sh"
+VERIFY_SCRIPT="$TEST_ROOT/../scripts/agent_deployment_verify.sh"
 ENV_FILE="$TEST_ROOT/.env"
 
 # 中文提示：重启场景也需要同样的入口脚本，确保 DNS 注册逻辑一致
@@ -18,6 +19,11 @@ if [[ ! -f "$ENTRYPOINT_SCRIPT" ]]; then
   exit 1
 fi
 
+if [[ ! -f "$VERIFY_SCRIPT" ]]; then
+  echo "[ERROR] agent verification script missing at $VERIFY_SCRIPT" >&2
+  exit 1
+fi
+
 if [[ ! -f "$TMP_ROOT/agent_binary_path" ]]; then
   echo "[ERROR] Agent binary path missing; rerun bootstrap" >&2
   exit 1
@@ -94,6 +100,7 @@ if ! docker run -d \
   -v "$TEST_ROOT/private/argus/etc:/private/argus/etc" \
   -v "$AGENT_BINARY:/usr/local/bin/argus-agent:ro" \
   -v "$ENTRYPOINT_SCRIPT:/usr/local/bin/agent-entrypoint.sh:ro" \
+  -v "$VERIFY_SCRIPT:/usr/local/bin/agent_deployment_verify.sh:ro" \
   -e MASTER_ENDPOINT=http://master.argus.com:3000 \
   -e REPORT_INTERVAL_SECONDS=2 \
   -e ARGUS_BUILD_UID="$AGENT_UID" \
diff --git a/src/agent/tests/scripts/07_down.sh b/src/agent/tests/scripts/08_down.sh
similarity index 89%
rename from src/agent/tests/scripts/07_down.sh
rename to src/agent/tests/scripts/08_down.sh
index b9674ee..4accf14 100755
--- a/src/agent/tests/scripts/07_down.sh
+++ b/src/agent/tests/scripts/08_down.sh
@@ -13,7 +13,7 @@ compose() {
   fi
 }
 
-docker container rm -f argus-agent-e2e >/dev/null 2>&1 || true
+docker container rm -f argus-agent-e2e argus-agent-env-e2e >/dev/null 2>&1 || true
 
 pushd "$TEST_ROOT" >/dev/null
 compose down --remove-orphans
diff --git a/src/agent/tests/scripts/08_verify_agent.sh b/src/agent/tests/scripts/08_verify_agent.sh
deleted file mode 100755
index 8b347b0..0000000
--- a/src/agent/tests/scripts/08_verify_agent.sh
+++ /dev/null
@@ -1,26 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-TEST_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
-VERIFY_SCRIPT="$(cd "$TEST_ROOT/.." && pwd)/scripts/agent_deployment_verify.sh"
-
-if ! docker ps --format '{{.Names}}' | grep -q '^argus-agent-e2e$'; then
-  echo "[WARN] agent container not running; skip verification"
-  exit 0
-fi
-
-if docker exec -i argus-agent-e2e bash -lc 'command -v curl >/dev/null && command -v jq >/dev/null'; then
-  echo "[INFO] curl/jq already installed in agent container"
-else
-  echo "[INFO] Installing curl/jq in agent container"
-  docker exec -i argus-agent-e2e bash -lc 'apt-get update >/dev/null 2>&1 && apt-get install -y curl jq >/dev/null 2>&1' || true
-fi
-
-if docker exec -i argus-agent-e2e bash -lc 'command -v /usr/local/bin/agent_deployment_verify.sh >/dev/null'; then
-  docker exec -i argus-agent-e2e /usr/local/bin/agent_deployment_verify.sh
-elif [[ -x "$VERIFY_SCRIPT" ]]; then
-  docker exec -i argus-agent-e2e "$VERIFY_SCRIPT"
-else
-  echo "[WARN] agent_deployment_verify.sh not found"
-fi
diff --git a/src/agent/tests/test_config_metadata.py b/src/agent/tests/test_config_metadata.py
new file mode 100644
index 0000000..390fd7d
--- /dev/null
+++ b/src/agent/tests/test_config_metadata.py
@@ -0,0 +1,133 @@
+from __future__ import annotations
+
+import os
+import unittest
+from contextlib import contextmanager
+from unittest.mock import patch
+
+from app.config import AgentConfig, load_config
+
+
+@contextmanager
+def temp_env(**overrides: str | None):
+    originals: dict[str, str | None] = {}
+    try:
+        for key, value in overrides.items():
+            originals[key] = os.environ.get(key)
+            if value is None:
+                os.environ.pop(key, None)
+            else:
+                os.environ[key] = value
+        yield
+    finally:
+        for key, original in originals.items():
+            if original is None:
+                os.environ.pop(key, None)
+            else:
+                os.environ[key] = original
+
+
+class LoadConfigMetadataTests(unittest.TestCase):
+    @patch("app.config.Path.mkdir")
+    def test_metadata_from_environment_variables(self, mock_mkdir):
+        with temp_env(
+            MASTER_ENDPOINT="http://master.local",
+            AGENT_HOSTNAME="dev-user-one-pod",
+            AGENT_ENV="prod",
+            AGENT_USER="ops",
+            AGENT_INSTANCE="node-1",
+        ):
+            config = load_config()
+
+        self.assertEqual(config.environment, "prod")
+        self.assertEqual(config.user, "ops")
+        self.assertEqual(config.instance, "node-1")
+        mock_mkdir.assert_called()
+
+    @patch("app.config.Path.mkdir")
+    def test_metadata_falls_back_to_hostname(self, mock_mkdir):
+        with temp_env(
+            MASTER_ENDPOINT="http://master.local",
+            AGENT_HOSTNAME="qa-team-abc-pod-2",
+            AGENT_ENV=None,
+            AGENT_USER=None,
+            AGENT_INSTANCE=None,
+        ):
+            config = load_config()
+
+        self.assertEqual(config.environment, "qa")
+        self.assertEqual(config.user, "team")
+        self.assertEqual(config.instance, "abc")
+        mock_mkdir.assert_called()
+
+    @patch("app.config.Path.mkdir")
+    def test_partial_environment_variables_fallback(self, mock_mkdir):
+        with temp_env(
+            MASTER_ENDPOINT="http://master.local",
+            AGENT_HOSTNAME="stage-ml-001-node",
+            AGENT_ENV="prod",
+            AGENT_USER=None,
+            AGENT_INSTANCE=None,
+        ):
+            config = load_config()
+
+        self.assertEqual(config.environment, "stage")
+        self.assertEqual(config.user, "ml")
+        self.assertEqual(config.instance, "001")
+        mock_mkdir.assert_called()
+
+    @patch("app.config.Path.mkdir")
+    def test_invalid_hostname_raises_error(self, mock_mkdir):
+        with temp_env(
+            MASTER_ENDPOINT="http://master.local",
+            AGENT_HOSTNAME="invalidhostname",
+            AGENT_ENV=None,
+            AGENT_USER=None,
+            AGENT_INSTANCE=None,
+        ):
+            with self.assertRaises(ValueError):
+                load_config()
+
+        mock_mkdir.assert_not_called()
+
+
+class CollectMetadataTests(unittest.TestCase):
+    @patch("app.collector._detect_ip_address", return_value="127.0.0.1")
+    @patch("app.collector._detect_gpu_count", return_value=0)
+    @patch("app.collector._detect_memory_bytes", return_value=1024)
+    @patch("app.collector._detect_cpu_count", return_value=8)
+    def test_collect_metadata_uses_config_fields(
+        self,
+        mock_cpu,
+        mock_memory,
+        mock_gpu,
+        mock_ip,
+    ):
+        config = AgentConfig(
+            hostname="dev-user-001-pod",
+            environment="prod",
+            user="ops",
+            instance="node-1",
+            node_file="/tmp/node.json",
+            version="1.0.0",
+            master_endpoint="http://master.local",
+            report_interval_seconds=60,
+            health_dir="/tmp/health",
+        )
+
+        from app.collector import collect_metadata
+
+        metadata = collect_metadata(config)
+
+        self.assertEqual(metadata["env"], "prod")
+        self.assertEqual(metadata["user"], "ops")
+        self.assertEqual(metadata["instance"], "node-1")
+        self.assertEqual(metadata["hostname"], "dev-user-001-pod")
+        self.assertEqual(metadata["ip"], "127.0.0.1")
+        self.assertEqual(metadata["cpu_number"], 8)
+        self.assertEqual(metadata["memory_in_bytes"], 1024)
+        self.assertEqual(metadata["gpu_number"], 0)
+
+
+if __name__ == "__main__":
+    unittest.main()