ncbi-sequence-fetch

ncbi-sequence-fetch is a skill for Claude Code, Codex from google-deepmind/science-skills. It costs 79 tokens per session (2,449 once invoked), scanned A, original, Apache-2.0.

A tool for retrieving protein and DNA sequences from NCBI, a public database of biological research and genetic information, using identifiers or search details.

In plain words
What is it for?
Use it to fetch sequences by accession number, gene and organism, location, publication, patent, or approximate organism and sequence length.
Why use it?
It removes the need to search NCBI manually and copy sequences from its website. It can also find related information such as coding regions, translated proteins, linked papers, and patent sequences.

Skill for Claude CodeCodex

About the project

Science Skills is a collection of add-ons that give AI agents structured instructions, scripts, and references for scientific research, including genomics, structural biology, cheminformatics, and literature search. Researchers use it to guide agents through specialized scientific tasks with information from databases and tools such as AlphaGenome, AFDB, and UniProt. The catalogue entries are individual skills from this collection.

google-deepmind/science-skills · 2,835 stars · on GitHub

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/google-deepmind/science-skills/ncbi_sequence_fetch
Any agent
npx skills add google-deepmind/science-skills --skill ncbi_sequence_fetch
Clone the repo
git clone --depth 1 https://github.com/google-deepmind/science-skills

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 ncbi-sequence-fetch

README.md
[![agentmods](https://agentmods.dev/badge/skills/google-deepmind/science-skills/ncbi_sequence_fetch.svg)](https://agentmods.dev/skills/google-deepmind/science-skills/ncbi_sequence_fetch)
Your own site
<a href="https://agentmods.dev/skills/google-deepmind/science-skills/ncbi_sequence_fetch"><img src="https://agentmods.dev/badge/skills/google-deepmind/science-skills/ncbi_sequence_fetch.svg" alt="Measured on agentmods" height="20"></a>
Per session 79 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,449 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00079 $0.02449
Opus 5 $0.00039 $0.01224
Sonnet 5 $0.00016 $0.00490
Haiku 4.5 $0.00008 $0.00245

Measured 5d ago against content hash 9cda15b57873, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ncbi-sequence-fetch 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 5d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/ncbi_fetch.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.

skills/ncbi_sequence_fetch/SKILL.md · 230 lines

How it starts

The opening of the file, as written. The whole thing — 230 lines — stays where its author put it; the contents beside it link to each section on GitHub.

NCBI Sequence Fetch

Prerequisites

  1. uv: Read the uv skill and follow its Setup instructions to ensure uv is installed and on PATH.
  2. User Notification: If .licenses/ncbi_sequence_fetch_LICENSE.txt does not already exist in the workspace root directory then (1) prominently notify the user to check the terms at https://www.ncbi.nlm.nih.gov/ and https://www.ncbi.nlm.nih.gov/home/about/policies/, then (2) create the file recording the notification text and timestamp.
  3. .env file: Make sure the .env file exists in your home directory. Create one if it does not exist.
  4. NCBI_API_KEY (optional): Raises the NCBI rate limit from 3 to 10 requests/second. The skill works without it, but a key is recommended if the user plans many queries or encounters a 429 error. You can register for a key for free at https://www.ncbi.nlm.nih.gov/account/settings/. You MUST use the safe credentials protocol in the credentials skill to check for and request this key if this skill looks relevant to the user's request.

Core Rules

  • Use the Wrapper: ALWAYS execute the provided helper scripts to query the database rather than accessing the database directly. The scripts automatically enforce the required rate limit gracefully.
  • API Key Support: If the user provides an NCBI_API_KEY in their environment, the query speed limits are automatically increased significantly.
  • Notification: If this skill is used, ensure this is mentioned in the output.

Overview

Wraps NCBI's Entrez E-utilities (efetch, esearch, elink, esummary) for retrieving protein and nucleotide sequences. Provides 10 subcommands covering the full range of sequence retrieval workflows:

  • fetch-protein — Direct protein accession lookup (GenPept, RefSeq)
  • fetch-nucleotide — Direct nucleotide accession lookup
  • cds-translate — Fetch CDS and translate to protein (3 methods)
  • search — Free-text search of any NCBI database
  • elink — Follow cross-database links (PubMed→Protein, etc.)
  • gene-protein — Search protein by gene name + organism
  • locus-protein — Search protein by locus tag + organism
  • pubmed-proteins — Find proteins linked to a PubMed article
  • patent-search — Extract protein sequences from patents
  • organism-length — Last-resort search by organism + exact AA length

Read the full file on GitHub · 230 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. 5d ago First seen · 230 lines · 79 tokens per session scan A 9cda15b57873

Subscribe to this mod's changes

ncbi-sequence-fetch is a skill published in the GitHub repository google-deepmind/science-skills (2,835 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 79 tokens to every session and 2,449 once invoked, about $0.0004 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.

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