bio-batch-downloads

bio-batch-downloads is a skill for Claude Code, Codex from thesecondfox/skill. It costs 42 tokens per session (2,940 once invoked), scanned A, original, MIT.

A tool for downloading many records or sequences from NCBI, a large public database of biological information. It searches results in batches and controls request speed.

In plain words
What is it for?
Use it for bulk sequence downloads, large NCBI queries, and production data retrieval with retries and rate limits.
Why use it?
It avoids manually downloading large result sets and helps prevent failed or blocked requests caused by sending too many requests at once.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it for bulk sequence downloads, large NCBI queries, and production data retrieval with retries and rate limits.

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Install with agentmods
npx agentmods add skills/thesecondfox/skill/bio-database-access-batch-downloads
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 thesecondfox/skill --skill bio-database-access-batch-downloads
Clone the repo
git clone --depth 1 https://github.com/thesecondfox/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 bio-batch-downloads

README.md
[![agentmods](https://agentmods.dev/badge/skills/thesecondfox/skill/bio-database-access-batch-downloads/github.svg)](https://agentmods.dev/skills/thesecondfox/skill/bio-database-access-batch-downloads)
Your own site
<a href="https://agentmods.dev/skills/thesecondfox/skill/bio-database-access-batch-downloads"><img src="https://agentmods.dev/badge/skills/thesecondfox/skill/bio-database-access-batch-downloads/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for bio-batch-downloads

Your own site · 80×15
<a href="https://agentmods.dev/skills/thesecondfox/skill/bio-database-access-batch-downloads"><img src="https://agentmods.dev/badge/skills/thesecondfox/skill/bio-database-access-batch-downloads.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,940 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00042 $0.02940
Opus 5.5 $0.00017 $0.01176
Sonnet 5.5 $0.00008 $0.00588
Haiku 4.5 $0.00004 $0.00294

Measured 1mo ago against content hash 5d19e3d39bc2, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

bio-batch-downloads scanned grade A with 1 finding 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 1mo ago.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

from urllib.error import HTTPError
Common_Skills/bio-database-access-batch-downloads/SKILL.md · 382 lines

How it starts

The opening of the file, as written. The whole thing — 382 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Version Compatibility

Reference examples tested with: BioPython 1.83+, Entrez Direct 21.0+

Before using code patterns, verify installed versions match. If versions differ:

  • Python: pip show <package> then help(module.function) to check signatures

If code throws ImportError, AttributeError, or TypeError, introspect the installed package and adapt the example to match the actual API rather than retrying.

Batch Downloads

"Download thousands of sequences from NCBI" → Search NCBI with history server, then batch-fetch results with rate limiting and retry logic.

  • Python: Entrez.esearch(), Entrez.efetch() with usehistory='y' (BioPython)

Download large numbers of records from NCBI efficiently using the history server, batching, and proper rate limiting.

Required Setup

from Bio import Entrez
import time

Entrez.email = '[email protected]'  # Required by NCBI
Entrez.api_key = 'your_api_key'          # Recommended for large downloads

Rate Limits

Authentication Requests/Second Delay Between
Email only 3 0.34 seconds
Email + API key 10 0.1 seconds

Get an API key at: https://www.ncbi.nlm.nih.gov/account/settings/

History Server

The history server stores search results on NCBI servers, enabling efficient batch retrieval without re-sending large ID lists.

How It Works

  1. Search with usehistory='y'
  2. Get WebEnv (session ID) and query_key (result set ID)
  3. Fetch results in batches using these identifiers
  4. Results stay available for ~15 minutes
# Search with history
handle = Entrez.esearch(db='nucleotide', term='human[orgn] AND mRNA[fkey]', usehistory='y')
search = Entrez.read(handle)
handle.close()

webenv = search['WebEnv']
query_key = search['QueryKey']
total = int(search['Count'])

print(f"Found {total} records, stored in history")

Core Pattern: Batch Download

Goal: Download all records matching a search query, handling NCBI rate limits and large result sets.

Read the full file on GitHub · 382 lines

Files

What ships with it

1 file 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. 1mo ago First seen · 382 lines · 42 tokens per session scan A 5d19e3d39bc2

Subscribe to this mod's changes

bio-batch-downloads is a skill published in the GitHub repository thesecondfox/skill (3 stars, last pushed 6mo ago), licensed MIT. It adds 42 tokens to every session and 2,940 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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