fix(coding): teach agents terminal env state persists

Tell coding agents to activate shell setup once per session instead of re-sourcing it before every command, and pin the existing LocalEnvironment env-snapshot behavior with regression tests.

tests/agent/test_coding_context.py

@@ -11,6 +11,12 @@ import pytest
 from agent import coding_context as cc
 
 
+def test_coding_guidance_advertises_persistent_terminal_state():
+    assert "Terminal state persists across calls" in cc.CODING_AGENT_GUIDANCE
+    assert "Activate a virtualenv" in cc.CODING_AGENT_GUIDANCE
+    assert "instead of re-sourcing it before every test command" in cc.CODING_AGENT_GUIDANCE
+
+
 def _git_init(path):
     env = {
         "GIT_AUTHOR_NAME": "t", "GIT_AUTHOR_EMAIL": "t@t",

tests/tools/test_local_shell_init.py

@@ -190,6 +190,49 @@ class TestSnapshotEndToEnd:
     """Spin up a real LocalEnvironment and confirm the snapshot sources
     extra init files."""
 
+    def test_exported_env_changes_persist_between_commands(self, tmp_path):
+        env = LocalEnvironment(cwd=str(tmp_path), timeout=15)
+        try:
+            first = env.execute(
+                'export HERMES_SESSION_ENV_PROBE="sticky"; '
+                'export PATH="/tmp/hermes-session-bin:$PATH"; '
+                'echo "first=$HERMES_SESSION_ENV_PROBE"'
+            )
+            second = env.execute(
+                'echo "second=$HERMES_SESSION_ENV_PROBE"; echo "PATH=$PATH"'
+            )
+        finally:
+            env.cleanup()
+
+        assert first["returncode"] == 0
+        assert second["returncode"] == 0
+        assert "first=sticky" in first.get("output", "")
+        output = second.get("output", "")
+        assert "second=sticky" in output
+        assert "/tmp/hermes-session-bin" in output
+
+    def test_venv_style_activation_persists_between_commands(self, tmp_path):
+        venv_bin = tmp_path / ".venv" / "bin"
+        venv_bin.mkdir(parents=True)
+        activate = venv_bin / "activate"
+        activate.write_text(
+            f'export VIRTUAL_ENV="{tmp_path / ".venv"}"\n'
+            f'export PATH="{venv_bin}:$PATH"\n'
+        )
+
+        env = LocalEnvironment(cwd=str(tmp_path), timeout=15)
+        try:
+            first = env.execute('source .venv/bin/activate; echo "venv=$VIRTUAL_ENV"')
+            second = env.execute('echo "venv=$VIRTUAL_ENV"; echo "PATH=$PATH"')
+        finally:
+            env.cleanup()
+
+        assert first["returncode"] == 0
+        assert second["returncode"] == 0
+        output = second.get("output", "")
+        assert f"venv={tmp_path / '.venv'}" in output
+        assert str(venv_bin) in output
+
     def test_snapshot_picks_up_init_file_exports(self, tmp_path, monkeypatch):
         init_file = tmp_path / "custom-init.sh"
         init_file.write_text(

tests/tools/test_terminal_tool.py

@@ -22,6 +22,14 @@ def test_searching_for_sudo_does_not_trigger_rewrite(monkeypatch):
     assert sudo_stdin is None
 
 
+def test_terminal_schema_advertises_persistent_env_state():
+    description = terminal_tool.TERMINAL_TOOL_DESCRIPTION
+
+    assert "exported environment variables persist between calls" in description
+    assert "activate a virtualenv" in description
+    assert "do not re-source the same environment before every command" in description
+
+
 def test_printf_literal_sudo_does_not_trigger_rewrite(monkeypatch):
     monkeypatch.delenv("SUDO_PASSWORD", raising=False)
     monkeypatch.delenv("HERMES_INTERACTIVE", raising=False)