ncbi-sequence-fetch

Retrieve NCBI protein and nucleotide sequences via Entrez E-utilities with JSON output.

2.7k|283|Updated May 13, 2026
One-click install
npx skills add https://github.com/google-deepmind/science-skills --skill ncbi-sequence-fetch
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: ncbi-sequence-fetch
Source: https://github.com/google-deepmind/science-skills/tree/main/skills/ncbi_sequence_fetch
Command: npx skills add https://github.com/google-deepmind/science-skills --skill ncbi-sequence-fetch

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires python-dotenv, scienceskillscommon, and includes scripts (resource) components.

What problem does it solve?

It eliminates the manual, error-prone work of finding, translating, and downloading biological sequences from NCBI when you only have accessions, gene names, locus tags, PubMed IDs, or patent numbers.

Core Features & Use Cases

  • NCBI E-utilities sequence retrieval: Pulls protein and nucleotide FASTA from NCBI using efetch/esearch and returns structured JSON results.
  • CDS translation workflows: Converts CDS or nucleotide records into protein sequences via pre-translated CDS, GenBank XML CDS extraction, or 6-frame ORF translation.
  • Flexible search entry points: Supports gene+organism, locus tag, PubMed-linked proteins, patent protein extraction, and a last-resort organism+length lookup.
  • Rate-limit and API-key support: Uses graceful throttling at 3 req/s (10 req/s with NCBI_API_KEY) and avoids asking users to paste secrets into chat.

Quick Start

Use the skill to fetch the protein FASTA for accession XP_022033624 by asking for a JSON output file location.

Frequently Asked Questions about ncbi-sequence-fetch

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

FAQPage Schema
How do I fetch protein and nucleotide sequences from NCBI using Entrez E-utilities?

You can fetch protein and nucleotide sequences from NCBI using Entrez E-utilities by defining operations in YAML helper scripts, which use efetch and esearch to return structured JSON results for your queries.

Can I retrieve a protein sequence from a nucleotide CDS record?

Yes, you can translate CDS or nucleotide records into protein sequences using pre-translated CDS extraction, GenBank XML CDS parsing, or 6-frame ORF translation workflows within the retrieval process.

Does retrieving sequences from NCBI support searches by locus tag or PubMed ID?

Retrieving NCBI sequences supports flexible search entry points including gene and organism names, locus tags, PubMed-linked proteins, patent-related protein extraction, and accession lookups.

How do I avoid NCBI rate limiting when fetching multiple sequences in a workflow?

To avoid NCBI rate limiting, the sequence retrieval process gracefully throttles requests at 3 per second, or 10 per second if you configure an optional NCBI_API_KEY with controlled credential handling.

What is the best way to get structured JSON outputs for NCBI FASTA sequences?

The best way to get structured JSON outputs for NCBI FASTA sequences is to use YAML-defined operations via helper scripts that query Entrez E-utilities and format the retrieved protein or nucleotide data into JSON.

Do I need to paste my NCBI API key directly into the chat to increase request limits?

No, you do not need to paste your NCBI API key into the chat, as the sequence retrieval process uses controlled credential handling to securely manage optional rate-limit increases via environment configuration.