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 skills add fergupa/claude_plugins --skill variance-analysisgit clone --depth 1 https://github.com/fergupa/claude_pluginsWrote 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/fergupa/claude_plugins/variance-analysis)<a href="https://agentmods.dev/skills/fergupa/claude_plugins/variance-analysis"><img src="https://agentmods.dev/badge/skills/fergupa/claude_plugins/variance-analysis/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/fergupa/claude_plugins/variance-analysis"><img src="https://agentmods.dev/badge/skills/fergupa/claude_plugins/variance-analysis.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00043 | $0.02599 |
| Opus 5.5 | $0.00017 | $0.01040 |
| Sonnet 5.5 | $0.00009 | $0.00520 |
| Haiku 4.5 | $0.00004 | $0.00260 |
Grade A, and why
variance-analysis 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 1mo 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.
This is a copy
98% identical to variance-analysis — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
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.
Variance Analysis
Important: This skill assists with variance analysis workflows but does not provide financial advice. All analyses should be reviewed by qualified financial professionals before use in reporting.
Techniques for decomposing variances, materiality thresholds, narrative generation, waterfall chart methodology, and budget vs actual vs forecast comparisons.
Variance Decomposition Techniques
Price / Volume Decomposition
The most fundamental variance decomposition. Used for revenue, cost of goods, and any metric that can be expressed as Price x Volume.
Formula:
Total Variance = Actual - Budget (or Prior)
Volume Effect = (Actual Volume - Budget Volume) x Budget Price
Price Effect = (Actual Price - Budget Price) x Actual Volume
Mix Effect = Residual (interaction term), or allocated proportionally
Verification: Volume Effect + Price Effect = Total Variance
(when mix is embedded in the price/volume terms)
Three-way decomposition (separating mix):
Volume Effect = (Actual Volume - Budget Volume) x Budget Price x Budget Mix
Price Effect = (Actual Price - Budget Price) x Budget Volume x Actual Mix
Mix Effect = Budget Price x Budget Volume x (Actual Mix - Budget Mix)
Example — Revenue variance:
- Budget: 10,000 units at $50 = $500,000
- Actual: 11,000 units at $48 = $528,000
- Total variance: +$28,000 favorable
- Volume effect: +1,000 units x $50 = +$50,000 (favorable — sold more units)
- Price effect: -$2 x 11,000 units = -$22,000 (unfavorable — lower ASP)
- Net: +$28,000
Rate / Mix Decomposition
Used when analyzing blended rates across segments with different unit economics.
Formula:
Rate Effect = Sum of (Actual Volume_i x (Actual Rate_i - Budget Rate_i))
Mix Effect = Sum of (Budget Rate_i x (Actual Volume_i - Expected Volume_i at Budget Mix))
Example — Gross margin variance:
- Product A: 60% margin, Product B: 40% margin
- Budget mix: 50% A, 50% B → Blended margin 50%
- Actual mix: 40% A, 60% B → Blended margin 48%
- Mix effect explains 2pp of margin compression
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.
- 1mo ago First seen · 266 lines · 43 tokens per session scan A ebfe7448e7c0
variance-analysis is a skill published in the GitHub repository fergupa/claude_plugins (2 stars, last pushed 8mo ago), licensed Apache-2.0. It adds 43 tokens to every session and 2,599 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 98% identical to variance-analysis, differing in 1 line, and is treated as a copy.
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