fix(gateway): make manual compression feedback truthful

tests/cli/test_manual_compress.py

@@ -0,0 +1,66 @@
+"""Tests for CLI manual compression messaging."""
+
+from unittest.mock import MagicMock, patch
+
+from tests.cli.test_cli_init import _make_cli
+
+
+def _make_history() -> list[dict[str, str]]:
+    return [
+        {"role": "user", "content": "one"},
+        {"role": "assistant", "content": "two"},
+        {"role": "user", "content": "three"},
+        {"role": "assistant", "content": "four"},
+    ]
+
+
+def test_manual_compress_reports_noop_without_success_banner(capsys):
+    shell = _make_cli()
+    history = _make_history()
+    shell.conversation_history = history
+    shell.agent = MagicMock()
+    shell.agent.compression_enabled = True
+    shell.agent._cached_system_prompt = ""
+    shell.agent._compress_context.return_value = (list(history), "")
+
+    def _estimate(messages):
+        assert messages == history
+        return 100
+
+    with patch("agent.model_metadata.estimate_messages_tokens_rough", side_effect=_estimate):
+        shell._manual_compress()
+
+    output = capsys.readouterr().out
+    assert "No changes from compression" in output
+    assert "✅ Compressed" not in output
+    assert "Rough transcript estimate: ~100 tokens (unchanged)" in output
+
+
+def test_manual_compress_explains_when_token_estimate_rises(capsys):
+    shell = _make_cli()
+    history = _make_history()
+    compressed = [
+        history[0],
+        {"role": "assistant", "content": "Dense summary that still counts as more tokens."},
+        history[-1],
+    ]
+    shell.conversation_history = history
+    shell.agent = MagicMock()
+    shell.agent.compression_enabled = True
+    shell.agent._cached_system_prompt = ""
+    shell.agent._compress_context.return_value = (compressed, "")
+
+    def _estimate(messages):
+        if messages == history:
+            return 100
+        if messages == compressed:
+            return 120
+        raise AssertionError(f"unexpected transcript: {messages!r}")
+
+    with patch("agent.model_metadata.estimate_messages_tokens_rough", side_effect=_estimate):
+        shell._manual_compress()
+
+    output = capsys.readouterr().out
+    assert "✅ Compressed: 4 → 3 messages" in output
+    assert "Rough transcript estimate: ~100 → ~120 tokens" in output
+    assert "denser summaries" in output