diff --git a/src/agentci/domain/commands.py b/src/agentci/domain/commands.py
index 6f76cb4..877d1eb 100644
--- a/src/agentci/domain/commands.py
+++ b/src/agentci/domain/commands.py
@@ -4,7 +4,7 @@ import re
 
 from agentci.domain.models import CommandName, JobKind, ParsedCommand
 
-COMMAND_RE = re.compile(r"^/agent[ \t]+([a-z]+)(?:[ \t]+([\s\S]*))?$")
+COMMAND_RE = re.compile(r"^/agent[ \t]+([a-z]+)(?:[ \t\r\n]+([\s\S]*))?$")
 
 
 class CommandError(ValueError):
@@ -46,4 +46,3 @@ def resolve_job_kind(command: ParsedCommand, *, is_pull_request: bool) -> JobKin
     if command.name not in mapping:
         raise CommandError(f"`/agent {command.name}` can only be used on a pull request.")
     return mapping[command.name]
-
diff --git a/tests/test_commands.py b/tests/test_commands.py
index 029490d..1dc320c 100644
--- a/tests/test_commands.py
+++ b/tests/test_commands.py
@@ -8,12 +8,31 @@ def test_ignores_non_commands() -> None:
     assert parse_command("please run /agent plan") is None
 
 
-def test_parses_multiline_message() -> None:
-    command = parse_command("/agent implement focus on API\nand add tests")
+@pytest.mark.parametrize("name", list(CommandName))
+@pytest.mark.parametrize("line_breaks", [1, 2, 5])
+def test_all_commands_accept_messages_after_any_number_of_lines(
+    name: CommandName, line_breaks: int
+) -> None:
+    command = parse_command(
+        f"/agent {name.value}{'\n' * line_breaks}"
+        "focus on the API\nand add tests"
+    )
     assert command is not None
-    assert command.name is CommandName.IMPLEMENT
-    assert command.message == "focus on API\nand add tests"
-    assert resolve_job_kind(command, is_pull_request=False) is JobKind.IMPLEMENT
+    assert command.name is name
+    assert command.message == "focus on the API\nand add tests"
+
+
+@pytest.mark.parametrize("name", list(CommandName))
+def test_all_commands_accept_crlf_separated_multiline_messages(
+    name: CommandName,
+) -> None:
+    command = parse_command(
+        f"/agent {name.value}\r\n\r\n\r\n"
+        "focus on the API\r\nand add tests"
+    )
+    assert command is not None
+    assert command.name is name
+    assert command.message == "focus on the API\r\nand add tests"
 
 
 def test_discuss_requires_message() -> None:
@@ -28,9 +47,21 @@ def test_rejects_wrong_location() -> None:
         resolve_job_kind(command, is_pull_request=False)
 
 
-def test_resolves_iterate_by_location() -> None:
-    command = parse_command("/agent iterate refine tests")
+@pytest.mark.parametrize(
+    ("body", "message"),
+    [
+        ("/agent iterate", ""),
+        ("/agent iterate refine tests", "refine tests"),
+        (
+            "/agent iterate\n\nkeep the API stable\nlimit changes to the parser",
+            "keep the API stable\nlimit changes to the parser",
+        ),
+    ],
+)
+def test_iterate_accepts_optional_message(body: str, message: str) -> None:
+    command = parse_command(body)
     assert command is not None
+    assert command.name is CommandName.ITERATE
+    assert command.message == message
     assert resolve_job_kind(command, is_pull_request=False) is JobKind.ITERATE_PLAN
     assert resolve_job_kind(command, is_pull_request=True) is JobKind.ITERATE_IMPLEMENT
-
diff --git a/tests/test_webhook.py b/tests/test_webhook.py
index 00b7bf3..70448ef 100644
--- a/tests/test_webhook.py
+++ b/tests/test_webhook.py
@@ -72,6 +72,27 @@ async def test_authorized_command_is_queued() -> None:
     assert "queued" in gitea.comments[0]
 
 
+async def test_iterate_message_is_preserved_on_queued_job() -> None:
+    storage = FakeStorage()
+    container = SimpleNamespace(storage=storage, gitea=FakeGitea())
+    event = _event_from_payload(
+        "delivery",
+        payload(
+            "/agent iterate\n\nkeep the API stable\nlimit changes to the parser",
+            is_pull=True,
+        ),
+    )
+    assert event is not None
+
+    response = await _handle_command(container, event)
+
+    assert response.status_code == 202
+    assert len(storage.jobs) == 1
+    assert storage.jobs[0].message == (
+        "keep the API stable\nlimit changes to the parser"
+    )
+
+
 async def test_non_command_is_ignored() -> None:
     container = SimpleNamespace(storage=FakeStorage(), gitea=FakeGitea())
     event = _event_from_payload("delivery", payload("ordinary discussion"))