fix(acp): avoid duplicate edit approval diffs

acp_adapter/tools.py

@@ -895,7 +895,7 @@ def _build_tool_complete_content(
     if len(display_result) > 5000:
         display_result = display_result[:4900] + f"\n... ({len(result)} chars total, truncated)"
 
-    if tool_name in {"write_file", "patch", "skill_manage"}:
+    if tool_name == "skill_manage":
         try:
             from agent.display import extract_edit_diff
 
@@ -936,22 +936,15 @@ def build_tool_start(
 
     if tool_name == "patch":
         mode = arguments.get("mode", "replace")
-        if mode == "replace":
-            path = arguments.get("path", "")
-            old = arguments.get("old_string", "")
-            new = arguments.get("new_string", "")
-            content = [acp.tool_diff_content(path=path, new_text=new, old_text=old)]
-        else:
-            patch_text = arguments.get("patch", "")
-            content = _build_patch_mode_content(patch_text)
+        path = arguments.get("path") or "patch input"
+        content = [_text(f"Preparing {mode} edit for {path}. Approval prompt shows the diff.")]
         return acp.start_tool_call(
             tool_call_id, title, kind=kind, content=content, locations=locations,
         )
 
     if tool_name == "write_file":
         path = arguments.get("path", "")
-        file_content = arguments.get("content", "")
-        content = [acp.tool_diff_content(path=path, new_text=file_content)]
+        content = [_text(f"Preparing write to {path}. Approval prompt shows the diff." if path else "Preparing file write. Approval prompt shows the diff.")]
         return acp.start_tool_call(
             tool_call_id, title, kind=kind, content=content, locations=locations,
         )

tests/acp/test_mcp_e2e.py

@@ -183,7 +183,7 @@ class TestMcpRegistrationE2E:
         assert "hello" in complete_event.content[0].content.text
         assert complete_event.raw_output is None
 
-    def test_patch_mode_tool_start_emits_diff_blocks_for_v4a_patch(self):
+    def test_patch_mode_tool_start_defers_diff_to_edit_approval_prompt(self):
         update = build_tool_start(
             "tc-1",
             "patch",
@@ -193,14 +193,9 @@ class TestMcpRegistrationE2E:
             },
         )
 
-        assert len(update.content) == 2
-        assert update.content[0].type == "diff"
-        assert update.content[0].path == "src/app.py"
-        assert update.content[0].old_text == "old line"
-        assert update.content[0].new_text == "new line"
-        assert update.content[1].type == "diff"
-        assert update.content[1].path == "src/new.py"
-        assert update.content[1].new_text == "hello"
+        assert len(update.content) == 1
+        assert update.content[0].type == "content"
+        assert "Approval prompt shows the diff" in update.content[0].content.text
 
     @pytest.mark.asyncio
     async def test_prompt_tool_results_paired_by_call_id(self, acp_agent, mock_manager):

tests/acp/test_tools.py

@@ -147,7 +147,7 @@ class TestBuildToolTitle:
 
 class TestBuildToolStart:
     def test_build_tool_start_for_patch(self):
-        """patch should produce a FileEditToolCallContent (diff)."""
+        """patch start should not duplicate the edit-approval diff."""
         args = {
             "path": "src/main.py",
             "old_string": "print('hello')",
@@ -156,24 +156,23 @@ class TestBuildToolStart:
         result = build_tool_start("tc-1", "patch", args)
         assert isinstance(result, ToolCallStart)
         assert result.kind == "edit"
-        # The first content item should be a diff
         assert len(result.content) >= 1
-        diff_item = result.content[0]
-        assert isinstance(diff_item, FileEditToolCallContent)
-        assert diff_item.path == "src/main.py"
-        assert diff_item.new_text == "print('world')"
-        assert diff_item.old_text == "print('hello')"
+        item = result.content[0]
+        assert isinstance(item, ContentToolCallContent)
+        assert "Approval prompt shows the diff" in item.content.text
+        assert "src/main.py" in item.content.text
 
     def test_build_tool_start_for_write_file(self):
-        """write_file should produce a FileEditToolCallContent (diff)."""
+        """write_file start should not duplicate the edit-approval diff."""
         args = {"path": "new_file.py", "content": "print('hello')"}
         result = build_tool_start("tc-w1", "write_file", args)
         assert isinstance(result, ToolCallStart)
         assert result.kind == "edit"
         assert len(result.content) >= 1
-        diff_item = result.content[0]
-        assert isinstance(diff_item, FileEditToolCallContent)
-        assert diff_item.path == "new_file.py"
+        item = result.content[0]
+        assert isinstance(item, ContentToolCallContent)
+        assert "Approval prompt shows the diff" in item.content.text
+        assert "new_file.py" in item.content.text
 
     def test_build_tool_start_for_terminal(self):
         """terminal should produce text content with the command."""
@@ -452,8 +451,8 @@ class TestBuildToolComplete:
         assert len(display_text) < 6000
         assert "truncated" in display_text
 
-    def test_build_tool_complete_for_patch_uses_diff_blocks(self):
-        """Completed patch calls should keep structured diff content for Zed."""
+    def test_build_tool_complete_for_patch_summarizes_without_repeating_diff(self):
+        """Completed patch calls should not duplicate the edit-approval diff."""
         patch_result = (
             '{"success": true, "diff": "--- a/README.md\\n+++ b/README.md\\n@@ -1 +1,2 @@\\n old line\\n+new line\\n", '
             '"files_modified": ["README.md"]}'
@@ -461,18 +460,17 @@ class TestBuildToolComplete:
         result = build_tool_complete("tc-p1", "patch", patch_result)
         assert isinstance(result, ToolCallProgress)
         assert len(result.content) == 1
-        diff_item = result.content[0]
-        assert isinstance(diff_item, FileEditToolCallContent)
-        assert diff_item.path == "README.md"
-        assert diff_item.old_text == "old line"
-        assert diff_item.new_text == "old line\nnew line"
+        item = result.content[0]
+        assert isinstance(item, ContentToolCallContent)
+        assert "✅ patch completed" in item.content.text
+        assert "README.md" in item.content.text
 
     def test_build_tool_complete_for_patch_falls_back_to_text_when_no_diff(self):
         result = build_tool_complete("tc-p2", "patch", '{"success": true}')
         assert isinstance(result, ToolCallProgress)
         assert isinstance(result.content[0], ContentToolCallContent)
 
-    def test_build_tool_complete_for_write_file_uses_snapshot_diff(self, tmp_path):
+    def test_build_tool_complete_for_write_file_summarizes_without_repeating_diff(self, tmp_path):
         target = tmp_path / "diff-test.txt"
         snapshot = type("Snapshot", (), {"paths": [target], "before": {str(target): None}})()
         target.write_text("hello from hermes\n", encoding="utf-8")
@@ -486,11 +484,10 @@ class TestBuildToolComplete:
         )
         assert isinstance(result, ToolCallProgress)
         assert len(result.content) == 1
-        diff_item = result.content[0]
-        assert isinstance(diff_item, FileEditToolCallContent)
-        assert diff_item.path.endswith("diff-test.txt")
-        assert diff_item.old_text is None
-        assert diff_item.new_text == "hello from hermes"
+        item = result.content[0]
+        assert isinstance(item, ContentToolCallContent)
+        assert "✅ write_file completed" in item.content.text
+        assert "diff-test.txt" in item.content.text
 
 
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