fix(acp): use modes for edit auto-approval

tests/acp/test_server.py

@@ -24,6 +24,7 @@ from acp.schema import (
     PromptResponse,
     ResumeSessionResponse,
     SessionModelState,
+    SessionModeState,
     SetSessionConfigOptionResponse,
     SetSessionModelResponse,
     SetSessionModeResponse,
@@ -52,31 +53,34 @@ def agent(mock_manager):
     """HermesACPAgent backed by a mock session manager."""
     return HermesACPAgent(session_manager=mock_manager)
 
-    @pytest.mark.asyncio
-    async def test_new_session_includes_edit_approval_config_option(self, agent):
-        resp = await agent.new_session(cwd="/tmp")
 
-        assert resp.config_options
-        option = resp.config_options[0]
-        assert option.id == "edit_approval_policy"
-        assert option.current_value == "ask"
-        assert {choice.value for choice in option.options} == {
-            "ask",
-            "workspace_session",
-            "session",
-        }
+@pytest.mark.asyncio
+async def test_new_session_exposes_edit_approvals_as_modes_not_config_options(agent):
+    resp = await agent.new_session(cwd="/tmp")
 
-    @pytest.mark.asyncio
-    async def test_set_config_option_persists_edit_approval_policy(self, agent):
-        resp = await agent.new_session(cwd="/tmp")
-        update = await agent.set_config_option(
-            "edit_approval_policy",
-            resp.session_id,
-            "workspace_session",
-        )
+    assert resp.config_options is None
+    assert isinstance(resp.modes, SessionModeState)
+    assert resp.modes.current_mode_id == "default"
+    assert [(mode.id, mode.name) for mode in resp.modes.available_modes] == [
+        ("default", "Default"),
+        ("accept_edits", "Accept Edits"),
+        ("dont_ask", "Don't Ask"),
+    ]
 
-        assert isinstance(update, SetSessionConfigOptionResponse)
-        assert update.config_options[0].current_value == "workspace_session"
+
+@pytest.mark.asyncio
+async def test_set_config_option_persists_edit_approval_policy_without_advertising_config(agent):
+    resp = await agent.new_session(cwd="/tmp")
+    update = await agent.set_config_option(
+        "edit_approval_policy",
+        resp.session_id,
+        "workspace_session",
+    )
+    state = agent.session_manager.get_session(resp.session_id)
+
+    assert isinstance(update, SetSessionConfigOptionResponse)
+    assert update.config_options == []
+    assert getattr(state, "mode", None) == "accept_edits"
 
 
 # ---------------------------------------------------------------------------
@@ -891,11 +895,11 @@ class TestSessionConfiguration:
     @pytest.mark.asyncio
     async def test_set_session_mode_returns_response(self, agent):
         new_resp = await agent.new_session(cwd="/tmp")
-        resp = await agent.set_session_mode(mode_id="chat", session_id=new_resp.session_id)
+        resp = await agent.set_session_mode(mode_id="accept_edits", session_id=new_resp.session_id)
         state = agent.session_manager.get_session(new_resp.session_id)
 
         assert isinstance(resp, SetSessionModeResponse)
-        assert getattr(state, "mode", None) == "chat"
+        assert getattr(state, "mode", None) == "accept_edits"
 
     @pytest.mark.asyncio
     async def test_router_accepts_stable_session_config_methods(self, agent):
@@ -904,7 +908,7 @@ class TestSessionConfiguration:
 
         mode_result = await router(
             "session/set_mode",
-            {"modeId": "chat", "sessionId": new_resp.session_id},
+            {"modeId": "accept_edits", "sessionId": new_resp.session_id},
             False,
         )
         config_result = await router(
@@ -918,8 +922,7 @@ class TestSessionConfiguration:
         )
 
         assert mode_result == {}
-        assert config_result["configOptions"]
-        assert config_result["configOptions"][0]["id"] == "edit_approval_policy"
+        assert config_result["configOptions"] == []
 
     @pytest.mark.asyncio
     async def test_router_accepts_unstable_model_switch_when_enabled(self, agent):

tests/acp/test_tools.py

@@ -2,6 +2,7 @@
 
 import pytest
 
+from acp_adapter.edit_approval import EditProposal
 from acp_adapter.tools import (
     TOOL_KIND_MAP,
     build_tool_complete,
@@ -174,6 +175,25 @@ class TestBuildToolStart:
         assert "Approval prompt shows the diff" in item.content.text
         assert "new_file.py" in item.content.text
 
+    def test_auto_approved_edit_start_shows_diff_content(self):
+        """Auto-approved edit starts need the diff because no approval card exists."""
+        args = {"path": "/tmp/acp.txt", "old_string": "old", "new_string": "new"}
+        result = build_tool_start(
+            "tc-auto-edit",
+            "patch",
+            args,
+            edit_diff=EditProposal("patch", "/tmp/acp.txt", "old\n", "new\n", args),
+        )
+
+        assert isinstance(result, ToolCallStart)
+        assert result.kind == "edit"
+        assert len(result.content) == 1
+        item = result.content[0]
+        assert isinstance(item, FileEditToolCallContent)
+        assert item.path == "/tmp/acp.txt"
+        assert item.old_text == "old\n"
+        assert item.new_text == "new\n"
+
     def test_build_tool_start_for_terminal(self):
         """terminal should produce text content with the command."""
         args = {"command": "ls -la /tmp"}