core/cli: multiline \"\"\" input and /edit via EDITOR

Add triple-quote block messages in the REPL and /edit to compose a turn
in $EDITOR (temp file). Empty multiline or empty edit cancels.

tests/test_cli/test_editor.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING
+from pathlib import Path
 
 import pytest
 from click.testing import CliRunner
@@ -14,9 +14,6 @@ from plyngent.cli.editor import (
     resolve_config_path,
 )
 
-if TYPE_CHECKING:
-    from pathlib import Path
-
 
 def test_get_editor(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.delenv("EDITOR", raising=False)
@@ -66,6 +63,42 @@ def test_open_in_editor_missing_editor(tmp_path: Path, monkeypatch: pytest.Monke
         open_in_editor(tmp_path / "x.toml", editor=None)
 
 
+def test_edit_text_in_editor(monkeypatch: pytest.MonkeyPatch) -> None:
+    from plyngent.cli.editor import edit_text_in_editor
+
+    def fake_run(argv: list[str], check: bool = False) -> object:
+        del check
+        path = Path(argv[-1])
+        _ = path.write_text("hello from editor\n", encoding="utf-8")
+
+        class Result:
+            returncode: int = 0
+
+        return Result()
+
+    monkeypatch.setenv("EDITOR", "true")
+    monkeypatch.setattr("plyngent.cli.editor.subprocess.run", fake_run)
+    assert edit_text_in_editor("seed") == "hello from editor"
+
+
+def test_edit_text_empty_cancels(monkeypatch: pytest.MonkeyPatch) -> None:
+    from plyngent.cli.editor import edit_text_in_editor
+
+    def fake_run(argv: list[str], check: bool = False) -> object:
+        del check
+        path = Path(argv[-1])
+        _ = path.write_text("  \n", encoding="utf-8")
+
+        class Result:
+            returncode: int = 0
+
+        return Result()
+
+    monkeypatch.setenv("EDITOR", "true")
+    monkeypatch.setattr("plyngent.cli.editor.subprocess.run", fake_run)
+    assert edit_text_in_editor("") is None
+
+
 def test_prompt_edit_no_editor(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.delenv("EDITOR", raising=False)
     assert prompt_edit_config(tmp_path / "p.toml") is False

tests/test_cli/test_input_text.py

@@ -0,0 +1,61 @@
+from __future__ import annotations
+
+from plyngent.cli.input_text import (
+    assemble_multiline,
+    finish_triple_quote_line,
+    parse_triple_quote_line,
+    read_repl_entry,
+)
+
+
+def test_parse_same_line_block() -> None:
+    assert parse_triple_quote_line('"""hello"""') == ("hello", True)
+    assert parse_triple_quote_line('  """hi"""  ') == ("hi", True)
+
+
+def test_parse_open_block() -> None:
+    assert parse_triple_quote_line('"""first') == ("first", False)
+    assert parse_triple_quote_line('"""') == ("", False)
+
+
+def test_parse_not_block() -> None:
+    assert parse_triple_quote_line("hello") is None
+    assert parse_triple_quote_line("/help") is None
+
+
+def test_finish_closer() -> None:
+    assert finish_triple_quote_line('"""') == ("", True)
+    assert finish_triple_quote_line('last line"""') == ("last line", True)
+    assert finish_triple_quote_line("middle") == ("middle", False)
+
+
+def test_assemble_multiline() -> None:
+    lines = iter(["line two", '"""'])
+    text = assemble_multiline(
+        '"""line one',
+        read_line=lambda: next(lines),
+    )
+    assert text == "line one\nline two"
+
+
+def test_assemble_empty_cancels() -> None:
+    lines = iter(['"""'])
+    assert assemble_multiline('"""', read_line=lambda: next(lines)) is None
+
+
+def test_read_repl_entry_slash() -> None:
+    assert read_repl_entry(read_line=lambda: "/status") == "/status"
+
+
+def test_read_repl_entry_simple() -> None:
+    assert read_repl_entry(read_line=lambda: "  hi  ") == "hi"
+
+
+def test_read_repl_entry_empty() -> None:
+    assert read_repl_entry(read_line=lambda: "   ") is None
+
+
+def test_read_repl_entry_multiline() -> None:
+    seq = iter(['"""a', "b", '"""'])
+    text = read_repl_entry(read_line=lambda: next(seq), echo=lambda _s: None)
+    assert text == "a\nb"

tests/test_cli/test_repl_commands.py

@@ -134,6 +134,20 @@ async def test_quit(state: ReplState) -> None:
     assert await handle_slash(state, "/quit") is False
 
 
+async def test_edit_sets_pending(
+    state: ReplState,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    monkeypatch.setattr(
+        "plyngent.cli.editor.edit_text_in_editor",
+        lambda *a, **k: "composed message",
+    )
+    assert await handle_slash(state, "/edit") is True
+    assert state.pending_user_text == "composed message"
+    assert "characters ready" in capsys.readouterr().out
+
+
 async def test_new_and_sessions(state: ReplState, capsys: pytest.CaptureFixture[str]) -> None:
     first = state.session_id
     assert await handle_slash(state, "/new other") is True