bio-duplicate-handling

bio-duplicate-handling is a skill for Claude Code, Codex from PKU-YuanGroup/OpenAI4S. It costs 39 tokens per session (4,189 once invoked), scanned A, a copy of bio-duplicate-handling, MIT.

A workflow for identifying and optionally removing duplicate DNA sequencing reads in BAM files. Duplicates are repeated copies of the same original molecule, often created during laboratory amplification.

In plain words
What is it for?
Use it to fix read pairing information, sort alignments, and mark or remove PCR and optical duplicates before variant analysis.
Why use it?
Duplicates can make coverage look higher than it is and distort allele frequencies, which may lead to incorrect variant calls.

Skill for Claude CodeCodex

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

Good fit Use it to fix read pairing information, sort alignments, and mark or remove PCR and optical duplicates before variant analysis.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pku-yuangroup/openai4s/bio-alignment-files-duplicate-handling
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-files-duplicate-handling
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-duplicate-handling

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-alignment-files-duplicate-handling"><img src="https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-alignment-files-duplicate-handling.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,189 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 98% 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 $0.00039 $0.04189
Opus 5 $0.00019 $0.02094
Sonnet 5 $0.00008 $0.00838
Haiku 4.5 $0.00004 $0.00419

Measured 12d ago against content hash 7ef875ece70c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

bio-duplicate-handling 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 12d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/markdup_pipeline.sh), 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

98% identical to bio-duplicate-handling — 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-files-duplicate-handling/SKILL.md · 379 lines

How it starts

The opening of the file, as written. The whole thing — 379 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Version Compatibility

Reference examples tested with: picard 3.1+, pysam 0.22+, samtools 1.19+

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

  • Python: pip show <package> then help(module.function) to check signatures
  • CLI: <tool> --version then <tool> --help to confirm flags

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

Duplicate Handling

"Remove PCR duplicates from my BAM file" -> Mark or remove duplicate reads using the fixmate-sort-markdup pipeline to prevent duplicate bias in variant calling.

  • CLI: samtools fixmate, samtools markdup (samtools)
  • Python: pysam.fixmate(), pysam.markdup() (pysam)

Mark and remove PCR/optical duplicates using samtools.

Why Remove Duplicates?

PCR duplicates are identical copies of the same original molecule, created during library preparation. They inflate coverage, bias allele frequencies, and create false positive variant calls. Optical duplicates are flowcell-proximity artifacts: on unpatterned flowcells they arise when the imaging software splits one cluster into two adjacent calls; on patterned flowcells (NovaSeq, NovaSeq X, NextSeq 1000/2000, HiSeq X/4000) the dominant source is ExAmp (exclusion-amplification) "pad-hopping", where a library molecule re-seeds a nearby nanowell.

When to Mark Duplicates -- and When NOT To

Standard samtools markdup is the right tool for some assays and actively harmful for others. The decision is assay-driven:

Assay Standard markdup? Recommended approach
Germline WGS / WES (PCR or PCR-free) YES samtools markdup (PCR-free still has ~0.5% optical duplicates on patterned flowcells)
Somatic tumor/normal (no UMI) YES Same
Exome / target capture YES (20-50% expected) samtools markdup
ChIP-seq MARK, do not remove Then use peak caller's auto-dup logic (macs3 --keep-dup auto)
CUT&RUN / CUT&Tag MARK, do not remove Same
ATAC-seq YES, BEFORE Tn5 +4/-5 shift Then shift coords for footprinting
Bulk RNA-seq (no UMIs) NO Duplicates are biological at highly-expressed loci; removing them biases DE proportional to expression
Bulk RNA-seq (with UMIs) NO umi_tools dedup
scRNA (10x, STARsolo, drop-seq) NO umi_tools dedup with CB+UB tags, or rely on Cell Ranger UMI counts
ctDNA / liquid biopsy / deep panel (UMI) NO fgbio GroupReadsByUmi -> CallDuplexConsensusReads
Twist / IDT / Roche UMI capture NO fgbio or Picard UmiAwareMarkDuplicatesWithMateCigar
Amplicon / hotspot panel (no UMI) NO Every read is a "duplicate" by coordinate; markdup erases the dataset. Use samtools ampliconclip instead -- see alignment-amplicon-clipping.
Amplicon / hotspot panel (UMI) NO fgbio consensus
Long-read native (ONT, PacBio HiFi unamplified) NO No PCR step; markdup is meaningless
PacBio HiFi amplicon YES (rare) pbmarkdup
Ancient DNA (aDNA) YES + mapDamage Run markdup, then mapDamage --rescale before variant calling
Microbiome 16S/ITS NO Read counts encode community structure

Read the full file on GitHub · 379 lines

Files

What ships with it

2 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.

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. 12d ago First seen · 379 lines · 39 tokens per session scan A 7ef875ece70c

Subscribe to this mod's changes

bio-duplicate-handling is a skill published in the GitHub repository PKU-YuanGroup/OpenAI4S (407 stars, last pushed yesterday), licensed MIT. It adds 39 tokens to every session and 4,189 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 98% identical to bio-duplicate-handling, differing in 12 lines, and is treated as a copy.

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