nfcore-sarek-wrapper

Orchestrates nf-core/sarek 3.8.1 for germline, tumor-only, and somatic variant calling with reproducibility bundles.

1.1k|257|Updated Feb 25, 2026
One-click install
npx skills add https://github.com/ClawBio/ClawBio --skill nfcore-sarek-wrapper
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: nfcore-sarek-wrapper
Source: https://github.com/ClawBio/ClawBio/tree/main/skills/nfcore-sarek-wrapper
Command: npx skills add https://github.com/ClawBio/ClawBio --skill nfcore-sarek-wrapper

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Running nf-core/sarek correctly requires hand-crafting samplesheets, choosing between iGenomes keys and explicit FASTA references, pairing tumor/normal statuses properly, and composing Nextflow profiles — mistakes that surface only as opaque mid-pipeline failures. This Skill validates everything before launch and produces a portable, checksummed reproducibility bundle for every run.

Core Features & Use Cases

  • Strict preflight validation: Checks samplesheet structure per pipeline step, tool/mode compatibility (germline, tumor-only, paired somatic), reference availability, Java/Nextflow versions, and resume-state drift before Nextflow launches.
  • Full sarek 3.8.1 surface: Exposes 154 audited passthrough parameters covering mapping, BQSR, variant calling (HaplotypeCaller, Mutect2, Strelka, Manta, ASCAT, and more), and VEP/SnpEff annotation, with profile composition for docker, singularity, arm64, gpu, and spark.
  • Reproducibility and provenance: Every run emits params.yaml, a self-contained commands.sh replay script, manifest.json, checksums.sha256, and seven provenance JSON files, plus opt-in handoff to downstream clinical interpretation skills.
  • Use Case: A researcher with tumor-normal paired WES FASTQs runs a somatic analysis with Mutect2, Strelka, and VEP annotation, then replays the identical run on a colleague's machine using the generated bundle.

Quick Start

Ask the agent to run nf-core/sarek germline variant calling on your samplesheet with HaplotypeCaller and VEP annotation using the GATK.GRCh38 genome, or request a demo run with the upstream test profile.

Frequently Asked Questions about nfcore-sarek-wrapper

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I run nf-core/sarek for somatic tumor-normal variant calling?

Provide a samplesheet with patient, sample, status (0=normal, 1=tumor), and FASTQ or BAM/CRAM columns, then run the wrapper with --tools mutect2,strelka,manta,vep and --genome GATK.GRCh38. Preflight validates pairing per patient before Nextflow launches.

What samplesheet format does nf-core/sarek require?

Sarek accepts CSV, TSV, YAML, or JSON samplesheets with patient and sample always required. Mapping steps need lane plus fastq_1/fastq_2, spring, or bam; later steps need bam+bai or cram+crai; annotate needs vcf. The wrapper normalizes paths and validates rows per step.

Can I use a custom reference FASTA instead of iGenomes?

Yes. Pass --fasta with your reference and the wrapper automatically sets igenomes_ignore so the default GATK.GRCh38 bundle is not loaded. Sarek builds missing .fai and .dict indices from the FASTA automatically.

Why does Mutect2 warn about PON and germline resources?

Mutect2 without a panel of normals returns recurrent technical artifacts mixed with true somatic calls, and without a germline resource no germline filtering is applied. The wrapper warns when neither explicit nor iGenomes-inherited resources are effective; supply --pon and --germline-resource for production runs.

Does the sarek wrapper work offline or on air-gapped machines?

Real runs with local inputs and references work offline, and NXF_OFFLINE=true avoids remote config fetches. However --demo requires network access because the upstream test profile downloads public test data from GitHub, and the arm64 profile enables Wave container provisioning.

How do I reproduce a completed sarek run on another machine?

Each run writes a reproducibility/ bundle containing a self-contained commands.sh that pins the Nextflow engine and pipeline version. Use the bundled remap_paths.py with --old/--new and --refs-old/--refs-new to rebase data and reference paths, then --verify before replaying.