Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/ArabelaTso/Skills-4-SEnpx agentmods add skills/arabelatso/skills-4-se/interval-difference-analyzerWrote 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/arabelatso/skills-4-se/interval-difference-analyzer)<a href="https://agentmods.dev/skills/arabelatso/skills-4-se/interval-difference-analyzer"><img src="https://agentmods.dev/badge/skills/arabelatso/skills-4-se/interval-difference-analyzer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/arabelatso/skills-4-se/interval-difference-analyzer"><img src="https://agentmods.dev/badge/skills/arabelatso/skills-4-se/interval-difference-analyzer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 5.1 | $0.00080 | $0.01508 |
| Opus 5 | $0.00040 | $0.00754 |
| Sonnet 5 | $0.00016 | $0.00302 |
| Haiku 4.5 | $0.00008 | $0.00151 |
Grade A, and why
interval-difference-analyzer 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 9d 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.
How it starts
The opening of the file, as written. The whole thing — 266 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Interval Difference Analyzer
Overview
Analyze differences in program intervals (variable value ranges) between two versions of a program to detect behavioral changes, identify potential bugs, and guide testing efforts.
Core Workflow
1. Setup Program Versions
Prepare both program versions for analysis:
OLD_VERSION=/path/to/old/program
NEW_VERSION=/path/to/new/program
TEST_SUITE=/path/to/tests # Optional
2. Extract Intervals
Extract interval information from both versions:
python scripts/interval_analyzer.py \
--program $OLD_VERSION \
--output old_intervals.json
python scripts/interval_analyzer.py \
--program $NEW_VERSION \
--output new_intervals.json
3. Compare Intervals
Compare intervals and identify differences:
python scripts/compare_intervals.py \
--old old_intervals.json \
--new new_intervals.json \
--output interval_diff_report.json
4. Review Report
Examine the generated report for:
- Added intervals (new variables or wider ranges)
- Removed intervals (deleted variables or narrower ranges)
- Modified intervals (changed bounds)
- Behavioral implications
- Testing recommendations
What Are Program Intervals?
Program intervals represent the possible ranges of values that variables can take during program execution.
Example:
def calculate_discount(price, discount_rate):
# Intervals:
# price: [0, 10000]
# discount_rate: [0.0, 1.0]
# discount: [0, 10000]
discount = price * discount_rate
return discount
Why intervals matter:
- Detect overflow/underflow risks
- Identify boundary condition changes
- Validate numeric computation correctness
- Guide test case generation
Interval Extraction Methods
Method 1: Static Analysis
Analyze code to infer possible value ranges without execution.
Method 2: Dynamic Analysis
Execute program with test inputs and observe actual ranges.
Method 3: Abstract Interpretation
What ships with it
4 files 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.
- 9d ago First seen · 266 lines · 80 tokens per session scan A 7a87c7122c67
interval-difference-analyzer is a skill published in the GitHub repository ArabelaTso/Skills-4-SE (252 stars, last pushed 22d ago), licensed Apache-2.0. It adds 80 tokens to every session and 1,508 once invoked, about $0.0004 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 2026-09-03.
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