bio-alignment-msa-statistics

bio-alignment-msa-statistics is a skill for Claude Code, Codex from PKU-YuanGroup/OpenAI4S. It costs 40 tokens per session (5,686 once invoked), scanned A, a copy of bio-alignment-msa-statistics, MIT.

A guide to measuring statistics from multiple sequence alignments, where related DNA or protein sequences are lined up by position.

In plain words
What is it for?
Use it to calculate pairwise identity, conservation scores, substitution counts, similarity measures, and entropy-based variation statistics.
Why use it?
Visual inspection alone does not reliably show how similar, conserved, or divergent the sequences are. Quantitative measures make alignment quality and evolutionary patterns easier to compare.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to calculate pairwise identity, conservation scores, substitution counts, similarity measures, and entropy-based variation statistics.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pku-yuangroup/openai4s/bio-alignment-msa-statistics
Install

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.

Any agent
npx skills add PKU-YuanGroup/OpenAI4S --skill bio-alignment-msa-statistics
Clone the repo
git clone --depth 1 https://github.com/PKU-YuanGroup/OpenAI4S

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for bio-alignment-msa-statistics

README.md
[![agentmods](https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-alignment-msa-statistics/github.svg)](https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-alignment-msa-statistics)
Your own site
<a href="https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-alignment-msa-statistics"><img src="https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-alignment-msa-statistics/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.

agentmods 80×15 button for bio-alignment-msa-statistics

Your own site · 80×15
<a href="https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-alignment-msa-statistics"><img src="https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-alignment-msa-statistics.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,686 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 95% copy Near-identical to another mod in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00040 $0.05686
Opus 5 $0.00020 $0.02843
Sonnet 5 $0.00008 $0.01137
Haiku 4.5 $0.00004 $0.00569

Measured 11d ago against content hash 02bb7d9ebe84, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

bio-alignment-msa-statistics 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 11d ago.

The scan reads SKILL.md. This mod also ships 8 executable files (scripts/capra_singh_jsd.py, scripts/conservation_profile.py, scripts/entropy_analysis.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Origin

This is a copy

95% identical to bio-alignment-msa-statistics — 12 lines 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.

skills/bioskills/bio-alignment-msa-statistics/SKILL.md · 458 lines

How it starts

The opening of the file, as written. The whole thing — 458 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Version Compatibility

Reference examples tested with: BioPython 1.83+, numpy 1.26+

Before using code patterns, verify installed versions match. If versions differ:

  • Python: pip show <package> then help(module.function) to check signatures

If code throws ImportError, AttributeError, or TypeError, introspect the installed package and adapt the example to match the actual API rather than retrying.

MSA Statistics

Calculate sequence identity, conservation scores, substitution counts, and other alignment metrics.

Required Import

Goal: Load modules for alignment I/O, substitution scoring, and statistical calculations.

Approach: Import AlignIO for reading alignments, Counter for column analysis, numpy for matrix operations, and math for entropy calculations.

from Bio import AlignIO
from Bio.Align import substitution_matrices
from collections import Counter
import numpy as np
import math

Pairwise Identity

"Calculate percent identity" -> Compute the fraction of identical aligned residues between sequence pairs.

Goal: Measure sequence similarity as percent identity for individual pairs or across all sequences in an alignment.

Approach: Count matching non-gap positions divided by total aligned positions; optionally compute a full N-by-N identity matrix.

Percent Identity Definitions

There are four common denominators, producing up to 11.5% difference on the same alignment. Combined with different alignment algorithms, variation reaches 22%. Always report which method was used.

Method Denominator Code
PID1 Aligned positions including internal gaps sum(a != '-' or b != '-' for a, b in zip(s1, s2))
PID2 Aligned residue pairs only (no gaps) sum(a != '-' and b != '-' for a, b in zip(s1, s2))
PID3 Shorter sequence length (ungapped) min(len(s1.replace('-', '')), len(s2.replace('-', '')))
PID4 Mean sequence length (ungapped) (len(s1.replace('-', '')) + len(s2.replace('-', ''))) / 2

Read the full file on GitHub · 458 lines

Changes

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.

  1. 11d ago First seen · 458 lines · 40 tokens per session scan A 02bb7d9ebe84

Subscribe to this mod's changes

bio-alignment-msa-statistics is a skill published in the GitHub repository PKU-YuanGroup/OpenAI4S (403 stars, last pushed today), licensed MIT. It adds 40 tokens to every session and 5,686 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to bio-alignment-msa-statistics, differing in 12 lines, and is treated as a copy.

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