feat(cli): add -e/--env flag for passing env vars as scrubbed secrets

crates/eryx-python/python/eryx/__main__.py

@@ -22,7 +22,7 @@
 
 import eryx
 
-from eryx._cli import add_sandbox_args, make_mcp_manager, make_net_config, make_resource_limits
+from eryx._cli import add_sandbox_args, make_mcp_manager, make_net_config, make_resource_limits, make_secrets
 
 
 def _build_parser() -> argparse.ArgumentParser:
@@ -90,6 +90,9 @@ def _run_once(code: str, args: argparse.Namespace, mcp_manager: object | None =
         kwargs["resource_limits"] = limits
     if net is not None:
         kwargs["network"] = net
+    secrets = make_secrets(args)
+    if secrets is not None:
+        kwargs["secrets"] = secrets
     if args.volume:
         kwargs["volumes"] = args.volume
     if mcp_manager is not None:
@@ -127,6 +130,9 @@ def _repl(args: argparse.Namespace, mcp_manager: object | None = None) -> int:
     net = make_net_config(args)
     if net is not None:
         kwargs["network"] = net
+    secrets = make_secrets(args)
+    if secrets is not None:
+        kwargs["secrets"] = secrets
     if args.volume:
         kwargs["volumes"] = args.volume
     if mcp_manager is not None:

crates/eryx-python/python/eryx/_cli.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import argparse
+import os
 
 import eryx
 
@@ -73,6 +74,17 @@ def add_sandbox_args(parser: argparse.ArgumentParser) -> None:
         help="path to MCP config file (implies --mcp, can be repeated)",
     )
 
+    env = parser.add_argument_group("environment")
+    env.add_argument(
+        "-e",
+        "--env",
+        action="append",
+        default=[],
+        metavar="KEY[=VALUE]",
+        help="pass environment variable to sandbox (scrubbed from output). "
+        "Use KEY=VALUE to set explicitly, or KEY to inherit from host",
+    )
+
     fs = parser.add_argument_group("filesystem")
     fs.add_argument(
         "-v",
@@ -107,6 +119,29 @@ def make_net_config(args: argparse.Namespace) -> eryx.NetConfig | None:
     return config
 
 
+def make_secrets(args: argparse.Namespace) -> dict | None:
+    """Build secrets dict from -e/--env CLI args, or None if no env vars.
+
+    Each -e spec is either KEY=VALUE (explicit) or KEY (inherit from host).
+    Values are passed as scrubbed secrets so they're redacted in output.
+    """
+    if not args.env:
+        return None
+    secrets = {}
+    for spec in args.env:
+        if "=" in spec:
+            key, value = spec.split("=", 1)
+        else:
+            key = spec
+            value = os.environ.get(key)
+            if value is None:
+                raise argparse.ArgumentTypeError(
+                    f"environment variable '{key}' is not set"
+                )
+        secrets[key] = {"value": value}
+    return secrets
+
+
 def make_mcp_manager(args: argparse.Namespace) -> object | None:
     """Create an MCP manager if --mcp or --mcp-config is specified."""
     if not args.mcp and not args.mcp_config:

crates/eryx-python/tests/test_cli.py

@@ -1,5 +1,6 @@
 """Tests for the eryx CLI (__main__.py)."""
 
+import os
 import subprocess
 import sys
 import textwrap
@@ -8,6 +9,7 @@
 import pytest
 
 from eryx.__main__ import main
+from eryx._cli import make_secrets
 
 
 class TestCliCommandExecution:
@@ -197,3 +199,99 @@ def test_piped_stdin_without_dash(self, capsys):
             assert result == 0
             captured = capsys.readouterr()
             assert "piped" in captured.out
+
+
+class TestMakeSecrets:
+    """Tests for the make_secrets helper."""
+
+    def test_no_env_returns_none(self):
+        args = _make_args(env=[])
+        assert make_secrets(args) is None
+
+    def test_explicit_key_value(self):
+        args = _make_args(env=["MY_KEY=my_value"])
+        secrets = make_secrets(args)
+        assert secrets == {"MY_KEY": {"value": "my_value"}}
+
+    def test_value_with_equals(self):
+        args = _make_args(env=["DSN=postgres://user:pass@host/db"])
+        secrets = make_secrets(args)
+        assert secrets == {"DSN": {"value": "postgres://user:pass@host/db"}}
+
+    def test_empty_value(self):
+        args = _make_args(env=["EMPTY="])
+        secrets = make_secrets(args)
+        assert secrets == {"EMPTY": {"value": ""}}
+
+    def test_inherit_from_host(self):
+        with patch.dict(os.environ, {"HOST_VAR": "host_value"}):
+            args = _make_args(env=["HOST_VAR"])
+            secrets = make_secrets(args)
+            assert secrets == {"HOST_VAR": {"value": "host_value"}}
+
+    def test_inherit_missing_var_raises(self):
+        # Ensure the var is not set
+        env = os.environ.copy()
+        env.pop("DEFINITELY_NOT_SET_12345", None)
+        with patch.dict(os.environ, env, clear=True):
+            args = _make_args(env=["DEFINITELY_NOT_SET_12345"])
+            with pytest.raises(Exception, match="not set"):
+                make_secrets(args)
+
+    def test_multiple_env_vars(self):
+        args = _make_args(env=["A=1", "B=2"])
+        secrets = make_secrets(args)
+        assert secrets == {"A": {"value": "1"}, "B": {"value": "2"}}
+
+
+class TestCliEnvFlag:
+    """Integration tests for -e/--env CLI flag."""
+
+    def test_env_var_available_in_sandbox(self, capsys):
+        result = main(["-e", "TEST_VAR=hello_sandbox", "-c", "import os; print(os.environ['TEST_VAR'])"])
+        assert result == 0
+        captured = capsys.readouterr()
+        # Value should be scrubbed (it's a secret)
+        assert "hello_sandbox" not in captured.out
+        assert "[REDACTED]" in captured.out
+
+    def test_env_var_value_is_scrubbed(self, capsys):
+        result = main(["-e", "SECRET=super_secret_42", "-c", "import os; print(os.environ['SECRET'])"])
+        assert result == 0
+        captured = capsys.readouterr()
+        assert "super_secret_42" not in captured.out
+        assert "[REDACTED]" in captured.out
+
+    def test_multiple_env_vars(self, capsys):
+        result = main([
+            "-e", "VAR_A=aaa",
+            "-e", "VAR_B=bbb",
+            "-c", "import os; print(os.environ['VAR_A'], os.environ['VAR_B'])",
+        ])
+        assert result == 0
+        captured = capsys.readouterr()
+        assert "aaa" not in captured.out
+        assert "bbb" not in captured.out
+
+    def test_env_inherit_from_host(self, capsys):
+        with patch.dict(os.environ, {"MY_HOST_VAR": "from_host"}):
+            result = main(["-e", "MY_HOST_VAR", "-c", "import os; print(os.environ['MY_HOST_VAR'])"])
+            assert result == 0
+            captured = capsys.readouterr()
+            assert "from_host" not in captured.out
+            assert "[REDACTED]" in captured.out
+
+    def test_long_form_env_flag(self, capsys):
+        result = main(["--env", "LONGFORM=works", "-c", "import os; print(os.environ['LONGFORM'])"])
+        assert result == 0
+        captured = capsys.readouterr()
+        assert "works" not in captured.out
+        assert "[REDACTED]" in captured.out
+
+
+def _make_args(**kwargs):
+    """Create a minimal argparse.Namespace for testing."""
+    import argparse
+    defaults = {"env": []}
+    defaults.update(kwargs)
+    return argparse.Namespace(**defaults)