diff --git a/openhands/agenthub/codeact_agent/tools/str_replace_editor.py b/openhands/agenthub/codeact_agent/tools/str_replace_editor.py
index d55b0d21c8..fc4999ece0 100644
--- a/openhands/agenthub/codeact_agent/tools/str_replace_editor.py
+++ b/openhands/agenthub/codeact_agent/tools/str_replace_editor.py
@@ -6,7 +6,10 @@ _DETAILED_STR_REPLACE_EDITOR_DESCRIPTION = """Custom editing tool for viewing, c
 * The `create` command cannot be used if the specified `path` already exists as a file
 * If a `command` generates a long output, it will be truncated and marked with `<response clipped>`
 * The `undo_edit` command will revert the last edit made to the file at `path`
-
+* All commands that include line numbers are 1-indexed
+* The `insert` command will insert a string after a specific line number in the file. Note that if you want to insert a string at the start of the file (line 1), you should use `insert_line=0`, and it will inserted *after* 0, so it will be on line 1.
+* The `view` command will show the file's contents in the indicated line number range, 1-indexed.
+* The line numbers are added by the tool as an aid for you, they are not part of the file.
 
 Before using this tool:
 1. Use the view tool to understand the file's contents and context
@@ -17,6 +20,7 @@ When making edits:
    - Ensure the edit results in idiomatic, correct code
    - Do not leave the code in a broken state
    - Always use absolute file paths (starting with /)
+   - Do not add line numbers to the `new_str` or `old_str` parameters
 
 CRITICAL REQUIREMENTS FOR USING THIS TOOL:
 
@@ -88,7 +92,7 @@ def create_str_replace_editor_tool(
                         'type': 'string',
                     },
                     'insert_line': {
-                        'description': 'Required parameter of `insert` command. The `new_str` will be inserted AFTER the line `insert_line` of `path`.',
+                        'description': 'Required parameter of `insert` command. The `new_str` will be inserted AFTER the line number `insert_line` of `path`. 0 is an allowed value for this parameter because it means the line before the first line of the file.',
                         'type': 'integer',
                     },
                     'view_range': {
diff --git a/poetry.lock b/poetry.lock
index c7b6b7dff9..e9f07377b1 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry 2.1.1 and should not be changed by hand.
+# This file is automatically @generated by Poetry 2.1.3 and should not be changed by hand.
 
 [[package]]
 name = "aiohappyeyeballs"
@@ -2871,7 +2871,7 @@ grpcio = {version = ">=1.49.1,<2.0dev", optional = true, markers = "python_versi
 grpcio-status = {version = ">=1.49.1,<2.0.dev0", optional = true, markers = "python_version >= \"3.11\" and extra == \"grpc\""}
 proto-plus = [
     {version = ">=1.25.0,<2.0.0dev", markers = "python_version >= \"3.13\""},
-    {version = ">=1.22.3,<2.0.0dev", markers = "python_version < \"3.13\""},
+    {version = ">=1.22.3,<2.0.0dev"},
 ]
 protobuf = ">=3.19.5,<3.20.0 || >3.20.0,<3.20.1 || >3.20.1,<4.21.0 || >4.21.0,<4.21.1 || >4.21.1,<4.21.2 || >4.21.2,<4.21.3 || >4.21.3,<4.21.4 || >4.21.4,<4.21.5 || >4.21.5,<6.0.0.dev0"
 requests = ">=2.18.0,<3.0.0.dev0"
@@ -6090,14 +6090,14 @@ voice-helpers = ["numpy (>=2.0.2)", "sounddevice (>=0.5.1)"]
 
 [[package]]
 name = "openhands-aci"
-version = "0.2.12"
+version = "0.2.13"
 description = "An Agent-Computer Interface (ACI) designed for software development agents OpenHands."
 optional = false
 python-versions = "<4.0,>=3.12"
 groups = ["main"]
 files = [
-    {file = "openhands_aci-0.2.12-py3-none-any.whl", hash = "sha256:8e7ffbca65049c5c31c8360892695ac3db1af4d59705d7d42283c0c0925ca452"},
-    {file = "openhands_aci-0.2.12.tar.gz", hash = "sha256:04500e1bb300ab4de2992c36c17f3234001655920424bdec3796e6fa5c706785"},
+    {file = "openhands_aci-0.2.13-py3-none-any.whl", hash = "sha256:f95447b23b5b66dd8f6be6c112f25c4fbe8d916d4b178864fa2ffbc8522e4367"},
+    {file = "openhands_aci-0.2.13.tar.gz", hash = "sha256:a34a73a5d2a5230a096578b71b98af2d2724e6ea47db6dec61b3f981e8cc3b38"},
 ]
 
 [package.dependencies]
@@ -8570,7 +8570,7 @@ description = "C version of reader, parser and emitter for ruamel.yaml derived f
 optional = false
 python-versions = ">=3.9"
 groups = ["main"]
-markers = "python_version < \"3.13\" and platform_python_implementation == \"CPython\""
+markers = "platform_python_implementation == \"CPython\" and python_version == \"3.12\""
 files = [
     {file = "ruamel.yaml.clib-0.2.12-cp310-cp310-macosx_13_0_arm64.whl", hash = "sha256:11f891336688faf5156a36293a9c362bdc7c88f03a8a027c2c1d8e0bcde998e5"},
     {file = "ruamel.yaml.clib-0.2.12-cp310-cp310-manylinux2014_aarch64.whl", hash = "sha256:a606ef75a60ecf3d924613892cc603b154178ee25abb3055db5062da811fd969"},
@@ -9962,7 +9962,7 @@ description = "A language and compiler for custom Deep Learning operations"
 optional = false
 python-versions = "*"
 groups = ["evaluation"]
-markers = "platform_system == \"Linux\" and platform_machine == \"x86_64\" and python_version < \"3.13\""
+markers = "platform_system == \"Linux\" and platform_machine == \"x86_64\" and python_version == \"3.12\""
 files = [
     {file = "triton-3.0.0-1-cp310-cp310-manylinux2014_x86_64.manylinux_2_17_x86_64.whl", hash = "sha256:e1efef76935b2febc365bfadf74bcb65a6f959a9872e5bddf44cc9e0adce1e1a"},
     {file = "triton-3.0.0-1-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.whl", hash = "sha256:5ce8520437c602fb633f1324cc3871c47bee3b67acf9756c1a66309b60e3216c"},
@@ -11249,4 +11249,4 @@ cffi = ["cffi (>=1.11)"]
 [metadata]
 lock-version = "2.1"
 python-versions = "^3.12,<3.14"
-content-hash = "3289d4f57295bf215347f6c2ad766788e8530bb18708cb81851dcbbf809a4457"
+content-hash = "e939bc50fd07aabf4d7bff3736ceba793a6490e6c68422233ac4ce7fe2bb302d"
diff --git a/pyproject.toml b/pyproject.toml
index e65d9a29db..b82c3e1e30 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -68,7 +68,7 @@ runloop-api-client = "0.32.0"
 libtmux = ">=0.37,<0.40"
 pygithub = "^2.5.0"
 joblib = "*"
-openhands-aci = "0.2.12"
+openhands-aci = "0.2.13"
 python-socketio = "^5.11.4"
 redis = "^5.2.0"
 sse-starlette = "^2.1.3"
diff --git a/tests/runtime/test_aci_edit.py b/tests/runtime/test_aci_edit.py
index 5a516d2031..d8a8417a28 100644
--- a/tests/runtime/test_aci_edit.py
+++ b/tests/runtime/test_aci_edit.py
@@ -437,7 +437,7 @@ def test_insert_invalid_line(temp_dir, runtime_cls, run_as_openhands):
         obs = runtime.run_action(action)
         logger.info(obs, extra={'msg_type': 'OBSERVATION'})
         assert 'Invalid `insert_line` parameter' in obs.content
-        assert 'It should be within the range of lines of the file' in obs.content
+        assert 'It should be within the range of allowed values' in obs.content
     finally:
         _close_test_runtime(runtime)