bio-bam-statistics

bio-bam-statistics is a skill for Claude Code, Codex from GPTomics/bioSkills. It costs 39 tokens per session (4,338 once invoked), scanned A, original, MIT.

A bioinformatics guide for measuring how sequencing reads align to a reference genome, including read counts, mapping rates, depth, and coverage. Coverage describes how much sequencing data supports each genome position.

In plain words
What is it for?
Generating flagstat, stats, depth, coverage, per-chromosome, and other alignment summaries from BAM files.
Why use it?
It turns alignment files into quality-control summaries, making it easier to spot low coverage or poor mapping before further analysis.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Generating flagstat, stats, depth, coverage, per-chromosome, and other alignment summaries from BAM…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/gptomics/bioskills/bam-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 GPTomics/bioSkills --skill bam-statistics
Clone the repo
git clone --depth 1 https://github.com/GPTomics/bioSkills

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-bam-statistics

README.md
[![agentmods](https://agentmods.dev/badge/skills/gptomics/bioskills/bam-statistics.svg)](https://agentmods.dev/skills/gptomics/bioskills/bam-statistics)
Your own site
<a href="https://agentmods.dev/skills/gptomics/bioskills/bam-statistics"><img src="https://agentmods.dev/badge/skills/gptomics/bioskills/bam-statistics.svg" alt="Measured on agentmods" 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 4,338 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 original No closer match found 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 $0.04338
Opus 5 $0.00019 $0.02169
Sonnet 5 $0.00008 $0.00868
Haiku 4.5 $0.00004 $0.00434

Measured 7d ago against content hash fb86e671b638, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

bio-bam-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 7d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (examples/qc_report.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

Copies of this mod

1 near-identical copy found in the catalogue:

alignment-files/bam-statistics/SKILL.md · 426 lines

How it starts

The opening of the file, as written. The whole thing — 426 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Version Compatibility

Reference examples tested with: 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.

BAM Statistics

"Get alignment statistics and coverage from my BAM file" -> Generate read counts, mapping rates, per-chromosome statistics, depth profiles, and coverage summaries.

  • CLI: samtools flagstat, samtools stats, samtools depth, samtools coverage (samtools)
  • Python: pysam.AlignmentFile with pileup() and get_index_statistics() (pysam)

Generate alignment statistics using samtools and pysam.

Quick Summary Commands

Question Best tool Why
Quick read counts by FLAG category samtools flagstat Fast; counts secondary+supp in totals
Per-chromosome counts samtools idxstats Fast (needs index); counts secondary+supp
Insert size, MAPQ, error, GC samtools stats -r ref.fa Comprehensive; feeds MultiQC
Per-position depth (small region) samtools depth or pysam pileup Slow on full genome
Per-position depth (genome-wide) mosdepth 3-10x faster than samtools depth
Per-region coverage (BED) mosdepth --by regions.bed Production default
Coverage histogram / cumulative mosdepth -t 4 --no-per-base Single-pass histogram
Breadth at depth thresholds mosdepth --thresholds 1,10,30,100 Standard exome QC
Targeted enrichment QC picard CollectHsMetrics PCT_OFF_BAIT, FOLD_80_BASE_PENALTY, AT/GC dropout
Cross-sample contamination verifybamid2, somalier FREEMIX < 0.01 expected

What Each Tool Counts (and Doesn't)

Counting category flagstat stats idxstats
Primary alignments in total minus supp raw total sequences mapped column
Secondary secondary line filtered out counted in mapped
Supplementary supplementary line filtered out counted in mapped
Mapping rate denominator total including supp primary only mapped+unmapped

Read the full file on GitHub · 426 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. 7d ago First seen · 426 lines · 39 tokens per session scan A fb86e671b638

Subscribe to this mod's changes

bio-bam-statistics is a skill published in the GitHub repository GPTomics/bioSkills (1,199 stars, last pushed 22d ago), licensed MIT. It adds 39 tokens to every session and 4,338 once invoked, about $0.0002 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 2026-08-30.

Related

Other skills, from other repositories

instrument-data-to-allotrope

Convert laboratory instrument output files (PDF, CSV, Excel, TXT) to Allotrope Simple Model (ASM) JSON format or flattened 2D CSV. Use this skill when scientists need to standardize instrument data for LIMS systems, data lakes, or downstream analysis. Supports auto-detection of instrument types. Outputs include full…

anthropics/knowledge-work-plugins · 123 tokens

matlab

Build, review, migrate, and safely plan MATLAB or GNU Octave numerical workflows, including arrays, tabular/time data, tests, projects, graphics, MAT files, and explicit Python interoperability.

K-Dense-AI/scientific-agent-skills · 42 tokens

exploratory-data-analysis

Perform bounded, local exploratory analysis of explicitly supported scientific files. Use for redacted CSV/TSV/JSON profiles; optional NumPy, HDF5, FASTA/FASTQ, and basic image metadata inspection; missingness/leakage audits; outlier and transformation sensitivity; and rigorous EDA report scaffolds. Other domain…

K-Dense-AI/scientific-agent-skills · 83 tokens

phylogenetics

Build and analyze phylogenetic trees using MAFFT (multiple alignment), IQ-TREE 2 (maximum likelihood), and FastTree (fast NJ/ML). Visualize with ETE3 or FigTree. For evolutionary analysis, microbial genomics, viral phylodynamics, protein family analysis, and molecular clock studies.

K-Dense-AI/scientific-agent-skills · 68 tokens

research-engineer

An uncompromising Academic Research Engineer. Operates with absolute scientific rigor, objective criticism, and zero flair. Focuses on theoretical correctness, formal verification, and optimal implementation across any required technology.

davila7/claude-code-templates · 43 tokens

mapping-to-snomed

Maps clinical concept spans extracted by OpenMed to SNOMED CT concepts through a USER-SUPPLIED terminology server (the user's own Ontoserver, Snowstorm, or UMLS/UTS), never a bundled vocabulary. Use when the user wants to code findings, disorders, procedures, body structures, or substances to SNOMED CT, run an ECL…

maziyarpanahi/openmed · 205 tokens