---
title: "Honor the NO_COLOR environment variable"
description: "The user pastes the specification of the NO_COLOR environment variable protocol from [no-color.org](https://no-color.org) into the aider chat."
type: skill
canonical_url: https://claudary.paisolsolutions.com/skills/no-color
source: "Claudary"
difficulty: intermediate
author: "Claude Code Knowledge Pack"
date: 2026-07-10T11:31:21.562Z
license: CC-BY-4.0
attribution: "Honor the NO_COLOR environment variable — Claudary (https://claudary.paisolsolutions.com/skills/no-color)"
---
# Honor the NO_COLOR environment variable
The user pastes the specification of the NO_COLOR environment variable protocol from [no-color.org](https://no-color.org) into the aider chat.
## Overview
---
parent: Example chat transcripts
---
# Honor the NO_COLOR environment variable
The user pastes the specification of the NO_COLOR environment variable protocol
from [no-color.org](https://no-color.org) into the aider chat.
Aider figures out which files need to be edited, and asks permission to make changes.
It then disables all the color and pretty-printing functions if NO_COLOR is
set, so the tool conforms to the specification.
The user then asks for a test case, which aider adds as well.
> $ aider
> Using git repo: .git
> Use /help to see in-chat commands.
#### Command-line software which adds ANSI color to its output by default should check for a NO_COLOR environment variable that, when present and not an empty string (regardless of its value), prevents the addition of ANSI color.
To implement this feature, we need to modify the `aider/io.py` file. Please make it *read-write* so I can provide the necessary changes.
> aider/io.py
> Add these files to the chat? y
Great! Now, I will make the necessary changes to check for the `NO_COLOR` environment variable and disable ANSI color when it is present and not an empty string.
```python
aider/io.py
<<<<<<< ORIGINAL
import os
=======
import os
import os.path
>>>>>>> UPDATED
```
```python
aider/io.py
<<<<<<< ORIGINAL
def __init__(
self,
pretty=True,
yes=False,
input_history_file=None,
chat_history_file=None,
input=None,
output=None,
user_input_color="blue",
tool_output_color=None,
tool_error_color="red",
):
self.user_input_color = user_input_color
self.tool_output_color = tool_output_color
self.tool_error_color = tool_error_color
self.input = input
self.output = output
self.pretty = pretty
self.yes = yes
self.input_history_file = input_history_file
if chat_history_file is not None:
self.chat_history_file = Path(chat_history_file)
else:
self.chat_history_file = None
if pretty:
self.console = Console()
else:
self.console = Console(force_terminal=True, no_color=True)
=======
def __init__(
self,
pretty=True,
yes=False,
input_history_file=None,
chat_history_file=None,
input=None,
output=None,
user_input_color="blue",
tool_output_color=None,
tool_error_color="red",
):
no_color = os.environ.get("NO_COLOR")
if no_color is not None and no_color != "":
pretty = False
self.user_input_color = user_input_color if pretty else None
self.tool_output_color = tool_output_color if pretty else None
self.tool_error_color = tool_error_color if pretty else None
self.input = input
self.output = output
self.pretty = pretty
self.yes = yes
self.input_history_file = input_history_file
if chat_history_file is not None:
self.chat_history_file = Path(chat_history_file)
else:
self.chat_history_file = None
self.console = Console(force_terminal=not pretty, no_color=not pretty)
>>>>>>> UPDATED
```
These changes will make the software check for the `NO_COLOR` environment variable and disable ANSI color when it is present and not an empty string.
> Applied edit to aider/io.py
> Applied edit to aider/io.py
> Commit 3218242 aider: Added check for NO_COLOR environment variable to disable ANSI color.
#### add a test
To add a test for the `NO_COLOR` environment variable, we will create a new test function in the `tests/test_io.py` file. Since this file does not exist, we will create it first.
```python
tests/test_io.py
<<<<<<< ORIGINAL
=======
import os
import unittest
from unittest.mock import patch
from aider.io import InputOutput
class TestInputOutput(unittest.TestCase):
def test_no_color_environment_variable(self):
with patch.dict(os.environ, {"NO_COLOR": "1"}):
io = InputOutput()
self.assertFalse(io.pretty)
if __name__ == "__main__":
unittest.main()
>>>>>>> UPDATED
```
This test function checks if the `pretty` attribute of the `InputOutput` class is set to `False` when the `NO_COLOR` environment variable is set.
> Allow creation of new file tests/test_io.py? y
> Add tests/test_io.py to git? y
> Applied edit to tests/test_io.py
> Commit 52a9df5 aider: Added a test function to check if the `pretty` attribute of the `InputOutput` class is set to `False` when the `NO_COLOR` environment variable is set.
#### /run pytest
> ============================= test session starts ==============================
> platform darwin -- Python 3.11.3, pytest-7.3.1, pluggy-1.0.0
> rootdir: /Users/gauthier/Projects/aider
> collected 25 items
>
> tests/test_coder.py ...... [ 24%]
> tests/test_commands.py . [ 28%]
> tests/test_io.py . [ 32%]
> tests/test_main.py .... [ 48%]
> tests/test_repomap.py ... [ 60%]
> tests/test_utils.py .......... [100%]
>
> ============================== 25 passed in 1.41s ==============================
>
> Add the output to the chat? y
---
Source: [Claudary](https://claudary.paisolsolutions.com/skills/no-color) · https://claudary.paisolsolutions.com