Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/thangchung/agent-engineering-experiment/calculator-utilsnpx skills add thangchung/agent-engineering-experiment --skill calculator-utilsgit clone --depth 1 https://github.com/thangchung/agent-engineering-experimentWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/thangchung/agent-engineering-experiment/calculator-utils)<a href="https://agentmods.dev/skills/thangchung/agent-engineering-experiment/calculator-utils"><img src="https://agentmods.dev/badge/skills/thangchung/agent-engineering-experiment/calculator-utils.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00036 | $0.00477 |
| Opus 5 | $0.00018 | $0.00238 |
| Sonnet 5 | $0.00007 | $0.00095 |
| Haiku 4.5 | $0.00004 | $0.00048 |
Grade A, and why
calculator-utils scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Calculator Utilities
A basic calculator utility that provides fundamental arithmetic operations via a Python script.
How to Use
Run the calculator script with an operation and numbers:
python scripts/calculator.py <operation> <numbers...>
Operations
Add
Adds all numbers together.
python scripts/calculator.py add 5 3
# Output: 8
python scripts/calculator.py add 10 20 30
# Output: 60
Subtract
Subtracts all subsequent numbers from the first number.
python scripts/calculator.py subtract 10 4
# Output: 6
python scripts/calculator.py subtract 100 25 15
# Output: 60
Multiply
Multiplies all numbers together.
python scripts/calculator.py multiply 6 7
# Output: 42
python scripts/calculator.py multiply 2 3 4
# Output: 24
Divide
Divides the first number by all subsequent numbers.
python scripts/calculator.py divide 20 4
# Output: 5.0
python scripts/calculator.py divide 100 2 5
# Output: 10.0
Error Handling
- Division by zero: Returns an error message
- Invalid input: Non-numeric values will show an error
- Missing arguments: Shows usage instructions
Examples
# Simple addition
python scripts/calculator.py add 100 50
# Output: 150
# Chain subtraction
python scripts/calculator.py subtract 1000 250 150 100
# Output: 500
# Multiply decimals
python scripts/calculator.py multiply 3.14 2
# Output: 6.28
# Division with decimals
python scripts/calculator.py divide 22 7
# Output: 3.142857142857143
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago First seen · 93 lines · 36 tokens per session scan A 47de937e7b01
calculator-utils is a skill published in the GitHub repository thangchung/agent-engineering-experiment (24 stars, last pushed 1mo ago), licensed MIT. It adds 36 tokens to every session and 477 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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