Agent skill

Archs4 Database

by jaechang-hits in jaechang-hits/SciAgent-Skills

Query ARCHS4 REST API for uniformly processed RNA-seq expression, tissue patterns, co-expression across 1M+ human/mouse samples.

CC-BY-4.0Auto-check passedResearch & Science

Install Archs4 Database

skills CLI
$ npx skills add jaechang-hits/SciAgent-Skills --skill archs4-database -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install jaechang-hits/SciAgent-Skills archs4-database --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/jaechang-hits/SciAgent-Skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/genomics-bioinformatics/databases/archs4-database .claude/skills/archs4-database && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
archs4-database
GitHub stars
371
Used in
1 other repo
Token cost
~6.6k tokens
SKILL.md length
1,255 words
Files
1
Skills in repo
169
Repo updated
First seen
Licence
CC-BY-4.0

At a glance

Query ARCHS4 REST API for uniformly processed RNA-seq expression, tissue patterns, co-expression across 1M+ human/mouse samples.

  • Works in 5 steps: Use z-score thresholds consistently:… → Sleep between batch queries: ARCHS4… → Download HDF5 for large-scale analyses:… → …
  • Tasks that involve Bioinformatics
  • SKILL.md covers Overview, When to Use, Prerequisites and Quick Start, plus 9 more sections
  • Calls pip; reaches maayanlab.cloud

What it does

Archs4 Database is an agent skill from jaechang-hits/SciAgent-Skills. Query ARCHS4 REST API for uniformly processed RNA-seq expression, tissue patterns, co-expression across 1M+ human/mouse samples. Retrieve z-scores, co-expressed genes, samples by metadata, HDF5 matrices. For variant population genetics use gnomad-database; for pathway enrichment use gget-genomic-databases (Enrichr).

Its SKILL.md is about 6.6k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Research & Science, covering Bioinformatics. The repository describes itself as: 197 bioinformatics & life science skills for Claude Code and AI agents — BixBench 92.0% accuracy. RNA-seq, single-cell, drug discovery, proteomics, and more. Powers OmicsHorizon. The licence is CC-BY-4.0.

When your agent uses it

  • Tasks that involve Bioinformatics

Example prompts

  • “/archs4-database”

Requirements

  • Python 3

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

  1. Use z-score thresholds consistently: Because z-scores are gene-specific, a z-score of 2.0 for a ubiquitous gene (GAPDH) and a…
  2. Sleep between batch queries: ARCHS4 enforces a soft rate limit of ~10 requests/second. Add time.sleep(0.1) between sequential gene queries…
  3. Download HDF5 for large-scale analyses: For queries covering 50+ genes or requiring per-sample expression values, the REST API is…
  4. Match gene symbol conventions by species: Human queries require HGNC uppercase symbols (e.g., TP53); mouse queries require MGI-style…
  5. Validate co-expression findings across datasets: ARCHS4 co-expression aggregates across all tissue types. A high correlation may be driven…

What it can do on your machine

Read from SKILL.md and the folder at commit 82c862c. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • pip

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Hosts in commands or code, which the agent is likely to contact:

    • maayanlab.cloud

    Also links to:

    • doi.org
    • github.com

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Archs4 Database loads about 6.6k tokens when it runs. Until then it costs about 83 tokens; SKILL.md has 1,255 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~83
When it runs · the whole SKILL.md, loaded when a task matches
~6.6k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from jaechang-hits/SciAgent-Skills at commit 82c862c, republished under its CC-BY-4.0 licence (© jaechang-hits). 1,255 words, ~6,599 tokens.

Download SKILL.mdSave it as .claude/skills/archs4-database/SKILL.md (or your agent's skills folder).
name
archs4-database
description
Query ARCHS4 REST API for uniformly processed RNA-seq expression, tissue patterns, co-expression across 1M+ human/mouse samples. Retrieve z-scores, co-expressed genes, samples by metadata, HDF5 matrices. For variant population genetics use gnomad-database; for pathway enrichment use gget-genomic-databases (Enrichr).
license
CC-BY-4.0

ARCHS4 Database

Overview

ARCHS4 (All RNA-seq and ChIP-seq Sample and Signature Search) is a resource of uniformly aligned and processed human and mouse RNA-seq data from NCBI GEO and SRA, covering 1 million+ samples. The REST API at https://maayanlab.cloud/archs4/api/ provides gene-level expression profiles, z-score normalized tissue expression, co-expression networks, and sample metadata search — all without authentication. Large-scale bulk queries can also use the downloadable HDF5 expression matrices.

When to Use

  • Retrieving tissue-specific or cell-type-specific expression z-scores for a gene of interest across hundreds of tissue types
  • Finding genes co-expressed with a query gene (co-expression network construction or guilt-by-association analysis)
  • Searching for RNA-seq samples by tissue, disease, or metadata keyword to identify candidate datasets for reanalysis
  • Comparing expression profiles of multiple genes across tissues to prioritize candidates for wet-lab follow-up
  • Accessing uniformly processed gene expression matrices (HDF5 format) for large-scale cross-study analysis
  • Validating differential expression results by checking whether a gene's expression direction matches population-level tissue profiles
  • Use omics-plotting SKILL to render bar charts and expression heatmaps from the query results
  • For variant-level population allele frequencies use gnomad-database; ARCHS4 provides expression evidence only
  • For Enrichr pathway enrichment from a gene list use gget-genomic-databases (gget enrichr); ARCHS4 is for expression lookups

Prerequisites

  • Python packages: requests, pandas, matplotlib, seaborn
  • Data requirements: gene symbols (HGNC format, e.g., TP53, BRCA1); sample GEO/SRA IDs for direct sample queries
  • Environment: internet connection; no API key or account required
  • Rate limits: ~10 requests/second; add time.sleep(0.1) between sequential gene queries to avoid throttling
bash
pip install requests pandas matplotlib seaborn

Quick Start

python
import requests

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def archs4_get(endpoint: str, params: dict = None) -> dict:
    """Send a GET request to the ARCHS4 API and return parsed JSON."""
    r = requests.get(f"{ARCHS4_BASE}/{endpoint}", params=params, timeout=30)
    r.raise_for_status()
    return r.json()

# Quick check: top tissues expressing TP53
data = archs4_get("meta/genes/TP53/zscore")
tissues = data.get("values", [])
print(f"TP53 tissue expression entries: {len(tissues)}")
top5 = sorted(tissues, key=lambda x: x.get("zscore", 0), reverse=True)[:5]
for t in top5:
    print(f"  {t['tissue']:<40}  z={t['zscore']:.2f}")
# TP53 tissue expression entries: 200
#   thymus                                   z=2.81
#   testis                                   z=2.44

Core API

Query 1: Gene Expression Z-Scores Across Tissues

Retrieve z-score normalized expression for a gene across all available tissue types. Z-scores are computed per-sample relative to the population distribution; positive values indicate above-average expression.

python
import requests
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def get_gene_tissue_zscore(gene_symbol: str, species: str = "human") -> pd.DataFrame:
    """Return tissue z-score expression profile for a gene.

    Parameters
    ----------
    gene_symbol : str
        HGNC gene symbol (e.g., 'TP53').
    species : str
        'human' or 'mouse' (default: 'human').
    """
    endpoint = f"meta/genes/{gene_symbol}/zscore"
    r = requests.get(
        f"{ARCHS4_BASE}/{endpoint}",
        params={"species": species},
        timeout=30
    )
    r.raise_for_status()
    data = r.json()
    records = data.get("values", [])
    df = pd.DataFrame(records)
    return df.sort_values("zscore", ascending=False).reset_index(drop=True)

df = get_gene_tissue_zscore("MYC")
print(f"MYC tissue z-scores: {len(df)} tissue types")
print(df[["tissue", "zscore"]].head(10).to_string(index=False))
# MYC tissue z-scores: 200
#                     tissue  zscore
#                      colon    3.12
#             small intestine    2.98
#                    placenta    2.74
python
# Query mouse tissues for a gene
df_mouse = get_gene_tissue_zscore("Myc", species="mouse")
print(f"Mouse Myc: top 5 tissues")
print(df_mouse[["tissue", "zscore"]].head(5).to_string(index=False))
Query 2: Co-expressed Genes

Find genes whose expression is most correlated with a query gene across all ARCHS4 samples. Useful for identifying pathway partners, regulators, or candidate targets.

python
import requests
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def get_coexpressed_genes(gene_symbol: str, top_n: int = 50,
                           species: str = "human") -> pd.DataFrame:
    """Return genes co-expressed with the query gene.

    Parameters
    ----------
    gene_symbol : str
        HGNC gene symbol.
    top_n : int
        Number of correlated genes to return (default: 50).
    species : str
        'human' or 'mouse' (default: 'human').
    """
    r = requests.get(
        f"{ARCHS4_BASE}/meta/genes/{gene_symbol}/correlations",
        params={"species": species, "limit": top_n},
        timeout=30
    )
    r.raise_for_status()
    data = r.json()
    records = data.get("values", [])
    df = pd.DataFrame(records)
    return df.sort_values("correlation", ascending=False).reset_index(drop=True)

coexp = get_coexpressed_genes("PCNA", top_n=20)
print(f"Top co-expressed genes with PCNA (n={len(coexp)}):")
print(coexp[["gene", "correlation"]].head(10).to_string(index=False))
# Top co-expressed genes with PCNA (n=20):
#   gene  correlation
#   RFC4         0.91
#   RFC2         0.89
#   MCM6         0.87
python
# Extract gene list for downstream enrichment
gene_list = coexp["gene"].tolist()
print(f"Co-expression gene list: {gene_list[:10]}")
# Pass gene_list to Enrichr or pathway analysis tools

Search for RNA-seq samples by metadata keyword (tissue, disease condition, cell type, treatment). Returns GEO/SRA sample identifiers with metadata fields.

python
import requests
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def search_samples(keyword: str, species: str = "human",
                   limit: int = 100) -> pd.DataFrame:
    """Search ARCHS4 samples by metadata keyword.

    Parameters
    ----------
    keyword : str
        Search term (e.g., 'breast cancer', 'liver', 'HeLa').
    species : str
        'human' or 'mouse'.
    limit : int
        Maximum number of samples to return.
    """
    r = requests.get(
        f"{ARCHS4_BASE}/samples/search",
        params={"query": keyword, "species": species, "limit": limit},
        timeout=30
    )
    r.raise_for_status()
    data = r.json()
    records = data.get("samples", [])
    return pd.DataFrame(records)

samples = search_samples("pancreatic cancer", limit=50)
print(f"Samples matching 'pancreatic cancer': {len(samples)}")
if len(samples) > 0:
    print(samples[["sample_id", "series_id", "title"]].head(5).to_string(index=False))
# Samples matching 'pancreatic cancer': 50
#   sample_id  series_id  title
#   GSM2345678  GSE123456  Pancreatic ductal adenocarcinoma - sample 1
Query 4: Gene-Level Metadata Summary

Retrieve summary statistics and metadata for a gene including the number of samples expressing it, expression percentile, and available annotation.

python
import requests

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def get_gene_metadata(gene_symbol: str, species: str = "human") -> dict:
    """Return metadata and expression summary for a gene."""
    r = requests.get(
        f"{ARCHS4_BASE}/meta/genes/{gene_symbol}",
        params={"species": species},
        timeout=30
    )
    r.raise_for_status()
    return r.json()

meta = get_gene_metadata("GAPDH")
print(f"Gene: {meta.get('gene_symbol', 'N/A')}")
print(f"Species: {meta.get('species', 'N/A')}")
print(f"Ensembl ID: {meta.get('ensembl_gene_id', 'N/A')}")
print(f"Description: {meta.get('description', 'N/A')[:80]}")
python
# Compare metadata for a panel of housekeeping genes
import time

housekeeping = ["GAPDH", "ACTB", "B2M", "HPRT1", "RPLP0"]
for gene in housekeeping:
    meta = get_gene_metadata(gene)
    print(f"  {gene:<8}  {meta.get('ensembl_gene_id', 'N/A')}")
    time.sleep(0.1)
Query 5: Visualization — Tissue Expression Barplot

Fetch the top-tissue z-scores, then read skills/data-visualization/omics-plotting/SKILL.md and follow its "Box / Violin / Bar" recipe on the exported CSV (→ figures/BRCA1_tissue_expression.png).

python
import requests
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def tissue_zscores(gene_symbol: str, top_n: int = 20, species: str = "human") -> pd.DataFrame:
    """Fetch top tissue z-scores for a gene and save for plotting."""
    r = requests.get(
        f"{ARCHS4_BASE}/meta/genes/{gene_symbol}/zscore",
        params={"species": species},
        timeout=30,
    )
    r.raise_for_status()
    df = pd.DataFrame(r.json().get("values", [])).sort_values("zscore", ascending=False).head(top_n)
    df.to_csv(f"{gene_symbol}_tissue_zscores.csv", index=False)
    return df

df = tissue_zscores("BRCA1", top_n=15)
print(f"Top tissues for BRCA1: {len(df)} -> BRCA1_tissue_zscores.csv")
# Render with the omics-plotting SKILL (`skills/data-visualization/omics-plotting/SKILL.md`) "Box / Violin / Bar" recipe (horizontal bar of zscore by tissue).
Query 6: HDF5 Bulk Data Access

Download or stream from ARCHS4's precomputed HDF5 expression matrices for large-scale cross-sample analysis. The HDF5 files contain gene × sample count matrices for human and mouse.

python
import requests

# HDF5 files are available for bulk download from the ARCHS4 data portal
# URL pattern: https://maayanlab.cloud/archs4/download#expression
# Human gene-level: human_gene_v2.6.h5
# Mouse gene-level: mouse_gene_v2.6.h5

def get_h5_download_urls() -> dict:
    """Return download URLs for ARCHS4 HDF5 expression matrices."""
    base = "https://maayanlab.cloud/archs4"
    return {
        "human_gene": f"{base}/files/human_gene_v2.6.h5",
        "mouse_gene": f"{base}/files/mouse_gene_v2.6.h5",
        "human_transcript": f"{base}/files/human_transcript_v2.6.h5",
        "mouse_transcript": f"{base}/files/mouse_transcript_v2.6.h5",
    }

urls = get_h5_download_urls()
for key, url in urls.items():
    print(f"  {key:<22}  {url}")

# To work with a downloaded HDF5 file:
try:
    import h5py
    import numpy as np

    h5_path = "human_gene_v2.6.h5"   # after download

    def extract_gene_from_h5(h5_path: str, gene_symbol: str,
                              n_samples: int = 1000) -> dict:
        """Extract expression values for a gene from the HDF5 matrix."""
        with h5py.File(h5_path, "r") as f:
            genes = [g.decode() for g in f["meta"]["genes"]["gene_symbol"][:]]
            if gene_symbol not in genes:
                raise ValueError(f"{gene_symbol} not found in HDF5")
            idx = genes.index(gene_symbol)
            expr = f["data"]["expression"][idx, :n_samples]
            sample_ids = [s.decode() for s in f["meta"]["samples"]["geo_accession"][:n_samples]]
        return {"gene": gene_symbol, "expression": expr, "sample_ids": sample_ids}

    result = extract_gene_from_h5(h5_path, "TP53", n_samples=500)
    print(f"TP53 expression: mean={result['expression'].mean():.2f},"
          f" max={result['expression'].max():.2f} (n={len(result['expression'])} samples)")
except ImportError:
    print("h5py not installed. Install with: pip install h5py")
except FileNotFoundError:
    print("HDF5 file not downloaded yet. Use the URLs above to download first.")

Key Concepts

Z-Score Normalization

ARCHS4 reports gene expression as z-scores computed relative to all samples for that gene. A z-score of 0 means expression at the population mean; a z-score of 2.0 means expression 2 standard deviations above the mean. Z-scores are more interpretable across datasets than raw counts because they account for library size differences and batch effects introduced by uniform alignment across studies.

python
# Example: Positive z-score = above-average expression for that gene
# z > 2.0 → top ~2.5% of samples for that gene
# z < -2.0 → bottom ~2.5% of samples for that gene
# Use absolute z-score thresholds consistently when comparing across genes
HDF5 vs REST API
Access methodBest forLimitations
REST API (/zscore, /correlations)Quick single-gene queries, explorationAggregated profiles only, no per-sample access
REST API (/samples/search)Discovering relevant datasetsReturns metadata, not expression values
HDF5 downloadBulk analysis, custom co-expression, MLRequires 30–60 GB disk; download once
Species and Gene Symbol Conventions

ARCHS4 indexes human samples using HGNC gene symbols (uppercase, e.g., TP53) and mouse samples using MGI symbols (first letter uppercase, e.g., Trp53). The species parameter accepts "human" or "mouse". Mixed-case or ensemble IDs will return empty results.

Common Workflows

Workflow 1: Multi-Gene Tissue Expression Heatmap

Goal: Compare tissue expression profiles of a gene panel and visualize as a heatmap to identify tissue-specific vs ubiquitous expression patterns.

python
import requests, time
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

gene_panel = ["MYC", "TP53", "BRCA1", "EGFR", "KRAS", "CDK4"]
top_n_tissues = 25

def get_tissue_zscores(gene: str) -> pd.Series:
    r = requests.get(
        f"{ARCHS4_BASE}/meta/genes/{gene}/zscore",
        params={"species": "human"},
        timeout=30
    )
    r.raise_for_status()
    records = r.json().get("values", [])
    df = pd.DataFrame(records).set_index("tissue")["zscore"]
    return df

# Build expression matrix (genes × tissues)
all_data = {}
for gene in gene_panel:
    try:
        all_data[gene] = get_tissue_zscores(gene)
        print(f"  Fetched {gene}")
    except Exception as e:
        print(f"  Warning: {gene} failed — {e}")
    time.sleep(0.1)

matrix = pd.DataFrame(all_data).T   # genes × tissues
# Select top tissues by max absolute z-score
tissue_importance = matrix.abs().max(axis=0).sort_values(ascending=False)
top_tissues = tissue_importance.head(top_n_tissues).index
matrix_subset = matrix[top_tissues]

# Save the gene × tissue matrix; render with the omics-plotting SKILL (`skills/data-visualization/omics-plotting/SKILL.md`) "Expression heatmap"
# recipe (RdBu_r, center=0) -> figures/archs4_panel_heatmap.png
matrix_subset.to_csv("archs4_panel_matrix.csv")
print(f"Panel matrix ready: {matrix_subset.shape} -> archs4_panel_matrix.csv")
Workflow 2: Co-expression Network Seed Expansion

Goal: Start from a seed gene, retrieve co-expressed partners, then query their co-expressed genes in turn to build a two-hop co-expression neighborhood.

python
import requests, time
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def get_coexp(gene: str, top_n: int = 20, species: str = "human") -> list:
    r = requests.get(
        f"{ARCHS4_BASE}/meta/genes/{gene}/correlations",
        params={"species": species, "limit": top_n},
        timeout=30
    )
    r.raise_for_status()
    return [rec["gene"] for rec in r.json().get("values", [])]

seed_gene = "PCNA"
min_correlation = 0.80

# Hop 1: direct co-expressed partners
hop1_genes = get_coexp(seed_gene, top_n=30)
print(f"Hop 1 partners of {seed_gene}: {len(hop1_genes)}")
time.sleep(0.1)

# Hop 2: co-expressed genes of each partner
edges = set()
for gene in hop1_genes[:10]:   # limit for demonstration
    partners = get_coexp(gene, top_n=20)
    for partner in partners:
        if partner != seed_gene:
            edges.add((gene, partner))
    time.sleep(0.1)

# Summarize the network
network_df = pd.DataFrame(list(edges), columns=["source", "target"])
hub_counts = network_df["source"].value_counts()
print(f"\nTwo-hop network: {len(edges)} edges")
print(f"Top hub genes:")
print(hub_counts.head(5))

network_df.to_csv(f"{seed_gene}_coexp_network.csv", index=False)
print(f"\nSaved {seed_gene}_coexp_network.csv")
Workflow 3: Sample Discovery and Dataset Summary

Goal: Search for samples by disease keyword, summarize how many GEO series are available, and export sample metadata for downstream reanalysis selection.

python
import requests, time
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def search_and_summarize(keyword: str, species: str = "human",
                          limit: int = 200) -> pd.DataFrame:
    """Search samples and return a tidy metadata DataFrame."""
    r = requests.get(
        f"{ARCHS4_BASE}/samples/search",
        params={"query": keyword, "species": species, "limit": limit},
        timeout=30
    )
    r.raise_for_status()
    records = r.json().get("samples", [])
    return pd.DataFrame(records)

keyword = "colorectal cancer"
df = search_and_summarize(keyword, limit=150)
print(f"Samples matching '{keyword}': {len(df)}")

if len(df) > 0:
    # Summarize by GEO series
    series_counts = df["series_id"].value_counts()
    print(f"\nTop GEO series (by sample count):")
    print(series_counts.head(8).to_string())

    # Export sample list
    df.to_csv(f"{keyword.replace(' ', '_')}_samples.csv", index=False)
    print(f"\nSaved {keyword.replace(' ', '_')}_samples.csv ({len(df)} samples)")
    print(f"Unique GEO series: {df['series_id'].nunique()}")

Key Parameters

ParameterEndpointDefaultRange / OptionsEffect
speciesAll gene endpoints"human""human", "mouse"Selects the species-specific sample index
limit/correlations, /samples/search1001–500Number of results returned
gene_symbol (path)/meta/genes/{gene}/zscore, /correlations—HGNC symbol (human) or MGI symbol (mouse)Query gene; case-sensitive
query/samples/search—free-text stringMetadata keyword search across title, tissue, source fields
offset/samples/search0integerPagination offset for large result sets
correlation (response field)/correlations—-1.0–1.0Pearson correlation coefficient; filter > 0.7 for high co-expression
zscore (response field)/zscore—continuous floatExpression z-score; > 2.0 = high expression
page_size (HDF5)HDF5 sliceallany integerNumber of samples to extract per read from HDF5
Show full SKILL.md (496 more words)Show less

Best Practices

  1. Use z-score thresholds consistently: Because z-scores are gene-specific, a z-score of 2.0 for a ubiquitous gene (GAPDH) and a tissue-restricted gene (TTR, liver) have different interpretive meaning. Always annotate which gene you are comparing and the tissue background.

  2. Sleep between batch queries: ARCHS4 enforces a soft rate limit of ~10 requests/second. Add time.sleep(0.1) between sequential gene queries to avoid 429 Too Many Requests errors.

  3. Download HDF5 for large-scale analyses: For queries covering 50+ genes or requiring per-sample expression values, the REST API is impractical. Download the HDF5 file once and use h5py slicing for fast matrix access; this avoids hitting rate limits and is 100× faster for bulk extraction.

  4. Match gene symbol conventions by species: Human queries require HGNC uppercase symbols (e.g., TP53); mouse queries require MGI-style symbols (e.g., Trp53). Using the wrong case returns empty results without an error.

  5. Validate co-expression findings across datasets: ARCHS4 co-expression aggregates across all tissue types. A high correlation may be driven by a single tissue or study. Cross-check with tissue-specific queries or manually inspect the top contributing GEO series.

Common Recipes

Recipe: Quick Tissue Specificity Check

When to use: Rapidly determine whether a gene is broadly expressed (housekeeping) or tissue-restricted before designing experiments.

python
import requests

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def tissue_specificity_summary(gene_symbol: str) -> None:
    """Print a summary of high and low expression tissues for a gene."""
    r = requests.get(
        f"{ARCHS4_BASE}/meta/genes/{gene_symbol}/zscore",
        params={"species": "human"},
        timeout=30
    )
    r.raise_for_status()
    records = r.json().get("values", [])
    zscores = [rec["zscore"] for rec in records if rec.get("zscore") is not None]
    top_high = sorted(records, key=lambda x: x.get("zscore", 0), reverse=True)[:5]
    top_low = sorted(records, key=lambda x: x.get("zscore", float("inf")))[:3]
    print(f"\n{gene_symbol} — {len(zscores)} tissues")
    print(f"  Range: [{min(zscores):.2f}, {max(zscores):.2f}]  "
          f"Mean: {sum(zscores)/len(zscores):.2f}")
    print("  High expression:")
    for t in top_high:
        print(f"    {t['tissue']:<35}  z={t['zscore']:.2f}")
    print("  Low expression:")
    for t in top_low:
        print(f"    {t['tissue']:<35}  z={t['zscore']:.2f}")

tissue_specificity_summary("TTR")   # Transthyretin — liver-specific
Recipe: Batch Gene Co-Expression Table

When to use: Generate a pairwise correlation table for a gene panel from a list of differentially expressed genes.

python
import requests, time
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

def batch_coexpr_table(gene_list: list, top_n: int = 10) -> pd.DataFrame:
    """For each gene in gene_list, return its top co-expressed genes."""
    rows = []
    for gene in gene_list:
        try:
            r = requests.get(
                f"{ARCHS4_BASE}/meta/genes/{gene}/correlations",
                params={"species": "human", "limit": top_n},
                timeout=30
            )
            r.raise_for_status()
            for rec in r.json().get("values", []):
                rows.append({
                    "query_gene": gene,
                    "coexp_gene": rec.get("gene"),
                    "correlation": rec.get("correlation"),
                })
            time.sleep(0.1)
        except Exception as e:
            print(f"Warning: {gene} skipped — {e}")
    return pd.DataFrame(rows)

deg_list = ["MYC", "CCND1", "CDK4", "RB1", "E2F1"]
coexp_table = batch_coexpr_table(deg_list, top_n=10)
print(f"Co-expression entries: {len(coexp_table)}")
print(coexp_table.groupby("query_gene")["coexp_gene"].count())
coexp_table.to_csv("deg_coexpression_table.csv", index=False)
print("Saved deg_coexpression_table.csv")
Recipe: Export Sample IDs for GEO Download

When to use: Identify relevant GEO accessions to download raw count matrices for a meta-analysis.

python
import requests
import pandas as pd

ARCHS4_BASE = "https://maayanlab.cloud/archs4/api/v1"

keyword = "glioblastoma"
r = requests.get(
    f"{ARCHS4_BASE}/samples/search",
    params={"query": keyword, "species": "human", "limit": 200},
    timeout=30
)
r.raise_for_status()
samples = pd.DataFrame(r.json().get("samples", []))
if len(samples) > 0:
    # Get unique GEO series accessions
    series = samples["series_id"].dropna().unique()
    print(f"Unique GEO series for '{keyword}': {len(series)}")
    for s in series[:10]:
        n = (samples["series_id"] == s).sum()
        print(f"  {s}  ({n} samples)")
    # Export series list for GEO download script
    pd.Series(series, name="geo_series").to_csv(
        f"{keyword}_geo_series.txt", index=False
    )
    print(f"\nSaved {keyword}_geo_series.txt")

Troubleshooting

ProblemCauseSolution
HTTP 404 for gene queryGene symbol not found in ARCHS4 indexVerify HGNC symbol spelling; check species parameter matches gene convention (human: uppercase, mouse: first-letter-upper)
HTTP 429 Too Many RequestsExceeded ~10 req/s rate limitAdd time.sleep(0.1) between requests; for batch queries use a 0.5 s delay
Empty values list in z-score responseGene is not expressed in any indexed tissue, or wrong speciesSwitch species; verify gene is protein-coding and has GEO coverage
Empty samples list from searchKeyword not matched in metadata fieldsTry broader or alternative keywords (e.g., "liver" instead of "hepatic")
HDF5 gene not foundSymbol mismatch between HDF5 version and queryCheck available genes in f["meta"]["genes"]["gene_symbol"][:]; try Ensembl ID or alias
requests.exceptions.TimeoutSlow API response under loadIncrease timeout=60; retry with exponential backoff
Z-scores all near zeroGene has very low or absent expression across tissuesCheck the gene's expression in raw counts; the gene may be non-coding or very lowly expressed
  • gnomad-database — Population variant frequencies; use after ARCHS4 to identify variants in highly expressed genes
  • gget-genomic-databases — Enrichr pathway enrichment for ARCHS4 co-expression gene lists (gget enrichr)
  • pydeseq2-differential-expression — Differential expression analysis on bulk RNA-seq; ARCHS4 HDF5 matrices can serve as reference cohorts

References

© jaechang-hits, CC-BY-4.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in skills/genomics-bioinformatics/databases/archs4-database of jaechang-hits/SciAgent-Skills.

Open the folder on GitHubat commit 82c862c

Used in 1 other repository

We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in jaechang-hits/SciAgent-Skills, which our catalogue first saw on October 7, 2026.

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Questions about Archs4 Database

What does Archs4 Database do?

Query ARCHS4 REST API for uniformly processed RNA-seq expression, tissue patterns, co-expression across 1M+ human/mouse samples. Archs4 Database is an agent skill from jaechang-hits/SciAgent-Skills. Query ARCHS4 REST API for uniformly processed RNA-seq expression, tissue patterns, co-expression across 1M+ human/mouse samples.

When should I use Archs4 Database?

Archs4 Database fits situations like: tasks that involve Bioinformatics.

How do I install Archs4 Database in Claude Code?

Run `npx skills add jaechang-hits/SciAgent-Skills --skill archs4-database -a claude-code`. Or copy the skill folder (skills/genomics-bioinformatics/databases/archs4-database in jaechang-hits/SciAgent-Skills) into .claude/skills/archs4-database in your project. Claude Code loads it when a task matches its description.

How do I install Archs4 Database in Codex?

Run `npx skills add jaechang-hits/SciAgent-Skills --skill archs4-database -a codex`. Or copy the skill folder (skills/genomics-bioinformatics/databases/archs4-database in jaechang-hits/SciAgent-Skills) into .agents/skills/archs4-database in your project. Codex loads it when a task matches its description.

Can I use Archs4 Database in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add jaechang-hits/SciAgent-Skills --skill archs4-database -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/archs4-database, .gemini/skills/archs4-database, .github/skills/archs4-database and .opencode/skills/archs4-database in your project.

What does Archs4 Database need to run?

Going by SKILL.md and its folder, Archs4 Database needs the command-line tools its instructions call (pip). Our summary lists: Python 3.

Does Archs4 Database access the network?

SKILL.md names 3 domains. In commands or code: maayanlab.cloud; the agent is likely to contact it when it follows the instructions. As links in the text: doi.org and github.com. This is read from the text; nothing was executed.

Is Archs4 Database safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Archs4 Database use?

Archs4 Database is published under the CC-BY-4.0 licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Archs4 Database use?

About 6.6k tokens (SKILL.md is roughly 26k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Archs4 Database?

Skills that share tags, products or a category with Archs4 Database: Alphagenome Single Variant Analysis (google-deepmind/science-skills, 3.2k stars), 13C Metabolic Flux Analysis (K-Dense-AI/scientific-agent-skills, 48k stars), Clinvar Database (google-deepmind/science-skills, 3.2k stars) and Metabolic Study Planner (aiming-lab/AutoResearchClaw, 15k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Archs4 Database?

jaechang-hits (a GitHub user) maintains it in jaechang-hits/SciAgent-Skills, which has 371 GitHub stars. The repository holds 169 skills in this directory. The repository was last updated on September 29, 2026.

Source: jaechang-hits/SciAgent-Skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.