Cursor Rules for FastLED WASM Project

CRITICAL: Python Command Usage

ALWAYS use

uv

to run Python code, NOT
python
or
python3
!

Command Guidelines:

✅ Use:
```
uv run <script.py>
```
✅ Use:
```
uv run -m <module>
```
✅ Use:
```
uv run python <script.py>
```
(if explicitly needed)
❌ NEVER use:
```
python <script.py>
```
❌ NEVER use:
```
python3 <script.py>
```

Examples:

Instead of

python src/fastled/cli.py

, use

uv run src/fastled/cli.py

Instead of
```
python -m pytest
```
, use
```
uv run -m pytest
```
Instead of
```
python3 build_exe.py
```
, use
```
uv run build_exe.py
```

Rationale:

This project uses
```
uv
```
for Python package and environment management
Using
```
python
```
or
```
python3
```
directly may use the wrong Python version or miss dependencies
```
uv
```
ensures consistent execution with the project's specified Python version and dependencies

Testing:

Follow the user rule: run unit tests with
```
bash test
```
For manual testing, use
```
uv run
```
prefix for any Python commands

Development Workflow:

Use
```
uv
```
for all Python execution
Ensure virtual environment is managed by
```
uv
```
Install dependencies with
```
uv add <package>
```
Run scripts with
```
uv run <script>
```

Emoji/Emoticon Usage

ALWAYS use the

EMO()

function for emojis, NEVER hardcode emojis directly!

Guidelines:

✅ Use:

from fastled.emoji_util import EMO

then

EMO('⚠️', 'WARNING:')

✅ Use:

from fastled.emoji_util import safe_print

for Unicode-safe printing

❌ NEVER use: hardcoded emojis like
```
print("⚠️ Warning")
```
❌ NEVER use: raw Unicode without fallback handling

Common Patterns:

Warning messages:
```
EMO('⚠️', 'WARNING:')
```
Success messages:
```
EMO('✅', 'SUCCESS:')
```
Error messages:
```
EMO('❌', 'ERROR:')
```
Info messages:
```
EMO('ℹ️', 'INFO:')
```
Playwright/browser:
```
EMO('🎭', '*')
```
Package/install:
```
EMO('📦', '*')
```

Rationale:

Windows cmd.exe has poor Unicode support and will crash on raw emojis
The
```
EMO()
```
function provides fallback text for systems that don't support emojis
Ensures consistent behavior across all platforms (Windows, macOS, Linux)
Prevents application crashes due to encoding issues

Examples:

# Good - with EMO function
from fastled.emoji_util import EMO
print(f"{EMO('⚠️', 'WARNING:')} Debug mode detected with Playwright installed")

# Bad - hardcoded emoji
print("⚠️ Debug mode detected with Playwright installed")

Additional Rules:

When suggesting Python commands, always prefix with
```
uv run
```
When creating scripts that execute Python, use
```
uv run
```
in the script
When documenting Python usage, emphasize
```
uv run
```
syntax
Update any existing scripts that use
```
python
```
or
```
python3
```
to use
```
uv run
```
When adding user-facing messages with emojis, always use the
```
EMO()
```
function

Cursor Rules for FastLED WASM Project

CRITICAL: Python Command Usage

ALWAYS use

uv

to run Python code, NOT
python
or
python3
!

Command Guidelines:

✅ Use:
```
uv run <script.py>
```
✅ Use:
```
uv run -m <module>
```
✅ Use:
```
uv run python <script.py>
```
(if explicitly needed)
❌ NEVER use:
```
python <script.py>
```
❌ NEVER use:
```
python3 <script.py>
```

Examples:

Instead of

python src/fastled/cli.py

, use

uv run src/fastled/cli.py

Instead of
```
python -m pytest
```
, use
```
uv run -m pytest
```
Instead of
```
python3 build_exe.py
```
, use
```
uv run build_exe.py
```

Rationale:

This project uses
```
uv
```
for Python package and environment management
Using
```
python
```
or
```
python3
```
directly may use the wrong Python version or miss dependencies
```
uv
```
ensures consistent execution with the project's specified Python version and dependencies

Testing:

Follow the user rule: run unit tests with
```
bash test
```
For manual testing, use
```
uv run
```
prefix for any Python commands

Development Workflow:

Use
```
uv
```
for all Python execution
Ensure virtual environment is managed by
```
uv
```
Install dependencies with
```
uv add <package>
```
Run scripts with
```
uv run <script>
```

Emoji/Emoticon Usage

ALWAYS use the

EMO()

function for emojis, NEVER hardcode emojis directly!

Guidelines:

✅ Use:

from fastled.emoji_util import EMO

then

EMO('⚠️', 'WARNING:')

✅ Use:

from fastled.emoji_util import safe_print

for Unicode-safe printing

❌ NEVER use: hardcoded emojis like
```
print("⚠️ Warning")
```
❌ NEVER use: raw Unicode without fallback handling

Common Patterns:

Warning messages:
```
EMO('⚠️', 'WARNING:')
```
Success messages:
```
EMO('✅', 'SUCCESS:')
```
Error messages:
```
EMO('❌', 'ERROR:')
```
Info messages:
```
EMO('ℹ️', 'INFO:')
```
Playwright/browser:
```
EMO('🎭', '*')
```
Package/install:
```
EMO('📦', '*')
```

Rationale:

Windows cmd.exe has poor Unicode support and will crash on raw emojis
The
```
EMO()
```
function provides fallback text for systems that don't support emojis
Ensures consistent behavior across all platforms (Windows, macOS, Linux)
Prevents application crashes due to encoding issues

Examples:

# Good - with EMO function
from fastled.emoji_util import EMO
print(f"{EMO('⚠️', 'WARNING:')} Debug mode detected with Playwright installed")

# Bad - hardcoded emoji
print("⚠️ Debug mode detected with Playwright installed")

Additional Rules:

When suggesting Python commands, always prefix with
```
uv run
```
When creating scripts that execute Python, use
```
uv run
```
in the script
When documenting Python usage, emphasize
```
uv run
```
syntax
Update any existing scripts that use
```
python
```
or
```
python3
```
to use
```
uv run
```
When adding user-facing messages with emojis, always use the
```
EMO()
```
function

Cursor Rules for FastLED WASM Project

Cursor Rules for FastLED WASM Project

CRITICAL: Python Command Usage

Command Guidelines:

Examples:

Rationale:

Testing:

Development Workflow:

Emoji/Emoticon Usage

Guidelines:

Common Patterns:

Rationale:

Examples:

Additional Rules:

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Cursor Rules for FastLED WASM Project

CRITICAL: Python Command Usage

Command Guidelines:

Examples:

Rationale:

Testing:

Development Workflow:

Emoji/Emoticon Usage

Guidelines:

Common Patterns:

Rationale:

Examples:

Additional Rules: