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Cn Math Expression
by
freedompixels
· GitHub ↗
· v1.0.0
· MIT-0
24
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0
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0
Active Installs
1
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Install in OpenClaw
/install cn-math-expression
Description
cn math expression
README (SKILL.md)
Math Expression Evaluator
Safely evaluate mathematical expressions with support for common functions.
Features
- Safe evaluation (no arbitrary code execution)
- Common mathematical functions: sqrt, sin, cos, tan, log
- Constants: pi, e
- Basic arithmetic: +, -, *, /, **, %
- Pure Python, no external dependencies
Supported Functions
| Function | Description | Example |
|---|---|---|
| sqrt(x) | Square root | sqrt(144) = 12 |
| sin(x) | Sine (radians) | sin(pi/2) = 1 |
| cos(x) | Cosine (radians) | cos(0) = 1 |
| tan(x) | Tangent (radians) | tan(pi/4) = 1 |
| log(x) | Natural log | log(e) = 1 |
| log10(x) | Base 10 log | log10(100) = 2 |
| abs(x) | Absolute value | abs(-5) = 5 |
| pow(x,y) | Power | pow(2,8) = 256 |
Supported Constants
pi= 3.141592653589793e= 2.718281828459045
Usage Examples
# Basic arithmetic
python3 scripts/math_eval.py --expr "2 + 3 * 4"
# Result: 14
# Using functions
python3 scripts/math_eval.py --expr "sqrt(144) + pow(2, 10)"
# Result: 1028.0
# Constants
python3 scripts/math_eval.py --expr "2 * pi * 10"
# Result: 62.8318...
# Complex expression
python3 scripts/math_eval.py --expr "log(pow(e, 5)) + sqrt(81)"
# Result: 14.0
Safety
The evaluator uses Python's eval() with a restricted namespace. Only mathematical functions and constants are available. No imports, no file access, no system commands.
Error Handling
If the expression is invalid or contains unsafe operations:
{"error": "name 'os' is not defined"}
Exit code 1 on error.
Technical Details
- Language: Python 3
- Dependencies: None (standard library only)
- License: MIT-0
Usage Guidance
Review before installing. Do not use this skill on untrusted expressions unless the eval-based implementation is replaced with a strict math parser and resource limits.
Capability Analysis
Type: OpenClaw Skill
Name: cn-math-expression
Version: 1.0.0
The skill implements a math expression evaluator in `scripts/math_eval.py` using Python's `eval()` function. While it attempts to sandbox execution by clearing `__builtins__` and providing a whitelist of functions, this approach is historically vulnerable to sandbox escape techniques that can lead to Remote Code Execution (RCE). It is classified as suspicious due to this critical security flaw, although there is no explicit evidence of intentional malicious logic or data exfiltration.
Capability Assessment
Purpose & Capability
The math-expression purpose is coherent, but the implementation gives the expression to Python eval instead of a strict math parser, which is more powerful than the stated calculator capability.
Instruction Scope
The usage model invites arbitrary --expr input and says unsafe operations will fail, but the artifacts do not show an AST whitelist, attribute restrictions, or resource limits.
Install Mechanism
There is no install script, no external dependency, and the only runnable code is the included standard-library Python script.
Credentials
For a simple math helper, raw Python eval is disproportionate because a crafted expression may execute unexpected Python behavior or consume local CPU/memory.
Persistence & Privilege
The provided artifacts show no credentials, network calls, file writes, background persistence, or privilege escalation behavior.
How to Use
- Make sure OpenClaw is installed (local or Docker)
- Run the install command in chat:
/install cn-math-expression - After installation, invoke the skill by name or use
/cn-math-expression - Provide required inputs per the skill's parameter spec and get structured output
Version History
v1.0.0
- Initial release of Cn Math Expression (version 1.0.0)
- Safely evaluates mathematical expressions using pure Python (no external dependencies)
- Supports common math functions: sqrt, sin, cos, tan, log, log10, abs, pow
- Includes mathematical constants: pi and e
- Handles basic arithmetic operations: +, -, *, /, **, %
- Protects against arbitrary code execution with a restricted namespace
- Error messages provided for invalid or unsafe expressions
Metadata
Frequently Asked Questions
What is Cn Math Expression?
cn math expression. It is an AI Agent Skill for Claude Code / OpenClaw, with 24 downloads so far.
How do I install Cn Math Expression?
Run "/install cn-math-expression" in the OpenClaw or Claude Code chat to install it in one step — no extra setup required.
Is Cn Math Expression free?
Yes, Cn Math Expression is completely free, licensed under MIT-0. You can download, install and use it at no cost.
Which platforms does Cn Math Expression support?
Cn Math Expression is cross-platform and runs anywhere OpenClaw / Claude Code is available (cross-platform).
Who created Cn Math Expression?
It is built and maintained by freedompixels (@freedompixels); the current version is v1.0.0.
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