fix(gateway): make compress responses truthful

gateway/run.py

@@ -5223,6 +5223,13 @@ class GatewayRunner:
             )
             tmp_agent._print_fn = lambda *a, **kw: None
 
+            compressor = tmp_agent.context_compressor
+            compress_start = compressor.protect_first_n
+            compress_start = compressor._align_boundary_forward(msgs, compress_start)
+            compress_end = compressor._find_tail_cut_by_tokens(msgs, compress_start)
+            if compress_start >= compress_end:
+                return "Nothing to compress yet (the transcript is still all protected context)."
+
             loop = asyncio.get_event_loop()
             compressed, _ = await loop.run_in_executor(
                 None,
@@ -5248,7 +5255,7 @@ class GatewayRunner:
 
             return (
                 f"🗜️ Compressed: {original_count} → {new_count} messages\n"
-                f"~{approx_tokens:,} → ~{new_tokens:,} tokens"
+                f"Rough transcript estimate: ~{approx_tokens:,} → ~{new_tokens:,} tokens"
             )
         except Exception as e:
             logger.warning("Manual compress failed: %s", e)

tests/gateway/test_compress_command.py

@@ -0,0 +1,163 @@
+"""Tests for gateway /compress truthfulness."""
+
+import sys
+import types
+from unittest.mock import MagicMock
+
+import pytest
+
+import gateway.run as gateway_run
+from gateway.config import Platform
+from gateway.platforms.base import MessageEvent
+from gateway.session import SessionSource
+
+
+def _make_event(text="/compress", platform=Platform.TELEGRAM, user_id="12345", chat_id="67890"):
+    source = SessionSource(
+        platform=platform,
+        user_id=user_id,
+        chat_id=chat_id,
+        user_name="testuser",
+    )
+    return MessageEvent(text=text, source=source)
+
+
+def _make_history(n_messages: int) -> list[dict]:
+    history = []
+    for i in range(n_messages):
+        history.append(
+            {
+                "role": "user" if i % 2 == 0 else "assistant",
+                "content": f"message {i}",
+            }
+        )
+    return history
+
+
+def _make_runner(history: list[dict], session_id: str = "sess-current"):
+    runner = object.__new__(gateway_run.GatewayRunner)
+    session_entry = MagicMock()
+    session_entry.session_id = session_id
+    session_entry.session_key = "telegram:12345:67890"
+
+    store = MagicMock()
+    store.get_or_create_session.return_value = session_entry
+    store.load_transcript.return_value = history
+    store.rewrite_transcript = MagicMock()
+    store.update_session = MagicMock()
+    store._save = MagicMock()
+
+    runner.session_store = store
+    return runner, session_entry
+
+
+class _NoOpCompressor:
+    protect_first_n = 3
+
+    def _align_boundary_forward(self, messages, idx):
+        return idx
+
+    def _find_tail_cut_by_tokens(self, messages, head_end):
+        return head_end
+
+
+class _NoOpAgent:
+    last_instance = None
+
+    def __init__(self, *args, **kwargs):
+        type(self).last_instance = self
+        self.session_id = kwargs["session_id"]
+        self.context_compressor = _NoOpCompressor()
+        self._print_fn = None
+        self._compress_context_calls = 0
+
+    def _compress_context(self, messages, system_message, *, approx_tokens=None):
+        self._compress_context_calls += 1
+        return messages, system_message
+
+
+class _CompressibleCompressor:
+    protect_first_n = 1
+
+    def _align_boundary_forward(self, messages, idx):
+        return idx
+
+    def _find_tail_cut_by_tokens(self, messages, head_end):
+        return 3
+
+
+class _CompressingAgent:
+    last_instance = None
+
+    def __init__(self, *args, **kwargs):
+        type(self).last_instance = self
+        self.session_id = kwargs["session_id"]
+        self.context_compressor = _CompressibleCompressor()
+        self._print_fn = None
+        self._compress_context_calls = 0
+
+    def _compress_context(self, messages, system_message, *, approx_tokens=None):
+        self._compress_context_calls += 1
+        self.session_id = "sess-compressed"
+        return (
+            [
+                {"role": "user", "content": "summary"},
+                {"role": "assistant", "content": "latest reply"},
+            ],
+            system_message,
+        )
+
+
+@pytest.mark.asyncio
+async def test_compress_command_reports_noop_truthfully(monkeypatch):
+    event = _make_event()
+    runner, session_entry = _make_runner(_make_history(4))
+
+    monkeypatch.setattr(gateway_run, "_resolve_runtime_agent_kwargs", lambda: {"api_key": "test-key"})
+    monkeypatch.setattr(gateway_run, "_resolve_gateway_model", lambda: "openai/test-model")
+    fake_run_agent = types.ModuleType("run_agent")
+    fake_run_agent.AIAgent = _NoOpAgent
+    monkeypatch.setitem(sys.modules, "run_agent", fake_run_agent)
+
+    result = await runner._handle_compress_command(event)
+
+    assert result == "Nothing to compress yet (the transcript is still all protected context)."
+    assert _NoOpAgent.last_instance is not None
+    assert _NoOpAgent.last_instance._compress_context_calls == 0
+    runner.session_store.rewrite_transcript.assert_not_called()
+    runner.session_store.update_session.assert_not_called()
+    runner.session_store._save.assert_not_called()
+    assert session_entry.session_id == "sess-current"
+
+
+@pytest.mark.asyncio
+async def test_compress_command_relabels_token_estimate_on_success(monkeypatch):
+    event = _make_event()
+    runner, session_entry = _make_runner(_make_history(6))
+
+    monkeypatch.setattr(gateway_run, "_resolve_runtime_agent_kwargs", lambda: {"api_key": "test-key"})
+    monkeypatch.setattr(gateway_run, "_resolve_gateway_model", lambda: "openai/test-model")
+    fake_run_agent = types.ModuleType("run_agent")
+    fake_run_agent.AIAgent = _CompressingAgent
+    monkeypatch.setitem(sys.modules, "run_agent", fake_run_agent)
+
+    result = await runner._handle_compress_command(event)
+
+    assert "🗜️ Compressed: 6 → 2 messages" in result
+    assert "Rough transcript estimate:" in result
+    assert "\n~" not in result
+    assert _CompressingAgent.last_instance is not None
+    assert _CompressingAgent.last_instance._compress_context_calls == 1
+    runner.session_store.rewrite_transcript.assert_called_once_with(
+        "sess-compressed",
+        [
+            {"role": "user", "content": "summary"},
+            {"role": "assistant", "content": "latest reply"},
+        ],
+    )
+    runner.session_store.update_session.assert_called_once_with(
+        session_entry.session_key,
+        last_prompt_tokens=0,
+    )
+    runner.session_store._save.assert_called_once()
+    assert session_entry.session_id == "sess-compressed"