Bc Calc

This skill evaluates arithmetic expressions using the Unix `bc` calculator. It accepts full `bc` syntax (addition, subtraction, multiplication, division, mod...

Security Scan

The skill is a small, coherent wrapper around the local bc calculator and its requirements and behavior match its description; no unexplained network, credential, or install activity is present.

Purpose & Capability

The name/description (evaluate bc expressions) matches the code and SKILL.md. The code launches the local 'bc' with -l and -q and returns output. Minor documentation mismatch: SKILL.md mentions a built-in 'pi' constant whereas standard bc does not define 'pi' automatically (users normally define it); this is a documentation inaccuracy rather than a security problem.

Instruction Scope

Runtime instructions and the implementation stay within scope: parse an expression from argv or stdin and feed it to bc. The skill does not read unrelated files, call external services, or exfiltrate data. Errors from bc are returned to the user. There is no vague instruction granting the agent broad discretionary access.

Install Mechanism

No install spec or remote downloads are present; the package contains only a small Node wrapper. It requires node and the system 'bc' binary — reasonable and proportional for the stated purpose.

Credentials

The skill requests no credentials or environment variables. One operational note: the wrapper invokes 'bc' via PATH (spawn('bc')), so if PATH is manipulated in the runtime environment a malicious binary named 'bc' could be executed. This is an operational risk of launching system binaries and not a problem unique to this skill.

Persistence & Privilege

The skill does not request persistent or elevated privileges, is not always-enabled, and does not modify other skills or global agent configuration.

Assessment

This skill is a thin wrapper that runs your local 'bc' process. Before installing: (1) ensure you trust the runtime environment and that the 'bc' binary on PATH is the legitimate system bc, (2) be aware the SKILL.md slightly overstates available constants (e.g., 'pi' may not be predefined in all bc implementations), and (3) if you run untrusted input in an environment where PATH might be controlled by others, consider hardcoding an absolute path to the bc binary or running it in a restricted environment. Otherwise the skill's behavior is proportional to its description.

Use the Unix bc calculator to evaluate arbitrary arithmetic expressions. The skill accepts the expression as a command‑line argument or via standard input.

When This Skill Applies

This skill activates when the user's request involves:

• Basic or advanced arithmetic calculations (addition, subtraction, multiplication, division, modulus)
• Full bc expressions (including scale, sqrt, pi, etc.)
• Any math expression evaluation request

How It Works

1. Parse the mathematical expression from the request or stdin.
2. Pass the expression to bc and capture the output.
3. Return the result, or the bc error message if the expression is invalid.

Usage Examples

# As a CLI command with a single expression
bc-calc "12+34*5"

# With piped input and scale
printf "scale=2; 1/3" | bc-calc

Installation

The skill can be installed with the ClawHub CLI:

openclaw install bc-calc

Or simply place the bc-calc directory under ~/.openclaw/workspace/skills.

Dependencies

• node (>=12)
• bc command‑line tool (usually pre‑installed on Linux/macOS)

Optional Flags

# Show help
bc-calc --help

The help flag displays usage instructions.

NOTE: The math‑library flag -l is now enabled by default, giving access to trigonometric and other advanced functions.

Available functions:

• s(x) : sine, in radians.
• c(x) : cosine, in radians.
• a(x) : arctangent, in radians.
• l(x) : natural logarithm.
• e(x) : e^x.
• j(n,x) : Bessel function of integer order n for x.