biopython

biopython is a skill for Claude Code, Codex from x-cmd/skill. It costs 76 tokens per session (3,529 once invoked), scanned A, a copy of biopython, Apache-2.0.

A Python toolkit for computational biology, covering DNA, RNA, and protein sequences, biological file formats, structures, and research databases.

In plain words
What is it for?
Use it to edit and convert sequences, parse FASTA or GenBank files, run BLAST searches, study protein structures, build evolutionary trees, and access biology databases.
Why use it?
It removes the need to build separate tools for common bioinformatics tasks such as reading sequence files or accessing NCBI and PubMed.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/x-cmd/skill/biopython
Any agent
npx skills add x-cmd/skill --skill biopython
Clone the repo
git clone --depth 1 https://github.com/x-cmd/skill

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 biopython

README.md
[![agentmods](https://agentmods.dev/badge/skills/x-cmd/skill/biopython.svg)](https://agentmods.dev/skills/x-cmd/skill/biopython)
Your own site
<a href="https://agentmods.dev/skills/x-cmd/skill/biopython"><img src="https://agentmods.dev/badge/skills/x-cmd/skill/biopython.svg" alt="Measured on agentmods" height="20"></a>
Per session 76 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,529 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 80% 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 $0.00076 $0.03529
Opus 5 $0.00038 $0.01765
Sonnet 5 $0.00015 $0.00706
Haiku 4.5 $0.00008 $0.00353

Measured yesterday against content hash 9079af86248f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

biopython 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 yesterday.

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

80% identical to biopython — 86 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.

data/k-dense-ai/biopython/SKILL.md · 443 lines

How it starts

The opening of the file, as written. The whole thing — 443 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Biopython: Computational Molecular Biology in Python

Overview

Biopython is a comprehensive set of freely available Python tools for biological computation. It provides functionality for sequence manipulation, file I/O, database access, structural bioinformatics, phylogenetics, and many other bioinformatics tasks. The current version is Biopython 1.85 (released January 2025), which supports Python 3 and requires NumPy.

When to Use This Skill

Use this skill when:

  • Working with biological sequences (DNA, RNA, or protein)
  • Reading, writing, or converting biological file formats (FASTA, GenBank, FASTQ, PDB, mmCIF, etc.)
  • Accessing NCBI databases (GenBank, PubMed, Protein, Gene, etc.) via Entrez
  • Running BLAST searches or parsing BLAST results
  • Performing sequence alignments (pairwise or multiple sequence alignments)
  • Analyzing protein structures from PDB files
  • Creating, manipulating, or visualizing phylogenetic trees
  • Finding sequence motifs or analyzing motif patterns
  • Calculating sequence statistics (GC content, molecular weight, melting temperature, etc.)
  • Performing structural bioinformatics tasks
  • Working with population genetics data
  • Any other computational molecular biology task

Core Capabilities

Biopython is organized into modular sub-packages, each addressing specific bioinformatics domains:

  1. Sequence Handling - Bio.Seq and Bio.SeqIO for sequence manipulation and file I/O
  2. Alignment Analysis - Bio.Align and Bio.AlignIO for pairwise and multiple sequence alignments
  3. Database Access - Bio.Entrez for programmatic access to NCBI databases
  4. BLAST Operations - Bio.Blast for running and parsing BLAST searches
  5. Structural Bioinformatics - Bio.PDB for working with 3D protein structures
  6. Phylogenetics - Bio.Phylo for phylogenetic tree manipulation and visualization
  7. Advanced Features - Motifs, population genetics, sequence utilities, and more

Installation and Setup

Install Biopython using pip (requires Python 3 and NumPy):

Read the full file on GitHub · 443 lines

Files

What ships with it

7 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. yesterday First seen · 443 lines · 76 tokens per session scan A 9079af86248f

Subscribe to this mod's changes

biopython is a skill published in the GitHub repository x-cmd/skill (26 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 76 tokens to every session and 3,529 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 80% identical to biopython, differing in 86 lines, and is treated as a copy.

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