skills/genomics-bioinformatics/clinpgx-database/SKILL.md
Query the ClinPGx (formerly PharmGKB) REST API plus the CPIC PostgREST companion API for pharmacogenomic clinical annotations, CPIC/DPWG dosing guidelines, gene-drug pairs, variant-drug associations, FDA/EMA drug labels, and PGx pathways. Two-host architecture: api.clinpgx.org for annotation records, api.cpicpgx.org for genotype→recommendation lookups. No auth. For germline pathogenicity use clinvar-database; for somatic cancer PGx use cosmic-database or opentargets-database; for drug bioactivity use chembl-database-bioactivity.
npx skillsauth add jaechang-hits/sciagent-skills clinpgx-databaseInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
3 of 9 scanners reported clean
Some scanners were skipped, did not run, or reported a non-clean status. Review each row below.
PharmGKB rebranded as ClinPGx in 2024 and the API moved from api.pharmgkb.org to api.clinpgx.org. The old host now returns 404/405; every example here uses the new endpoints. Two complementary APIs are used together:
api.clinpgx.org/v1) — record-style access to genes, drugs, variants, clinical annotations, guideline annotations, drug labels, and pathways. Responses wrap data as {"data": [...], "status": "success"}. Filters use dotted property paths (e.g. relatedChemicals.name=clopidogrel, levelOfEvidence.term=1A).api.cpicpgx.org/v1) — relational lookup of genotype → drug recommendation rows. PostgREST filter syntax (column=eq.value, JSON cs.{...} for jsonb containment). Returns flat JSON arrays.Use ClinPGx for what is known about a gene/drug/variant; use CPIC for how to prescribe given a phenotype. The pattern is ClinPGx for annotations, CPIC for recommendations.
data/clinicalAnnotationdata/guidelineAnnotationdata/{gene,drug,variant}POST /site/searchdata/labelclinvar-databasecosmic-database or opentargets-databaserequests, pandas — both already in standard environmentstime.sleep(0.3–0.5) between sequential calls. CPIC is more permissive.If you are inside a pixi/conda environment that already provides requests and pandas, skip the install — invoke scripts with pixi run python ....
pip install requests pandas
import requests
CLINPGX = "https://api.clinpgx.org/v1"
CPIC = "https://api.cpicpgx.org/v1"
# CPIC genotype → recommendation: clopidogrel + CYP2C19 Poor Metabolizer
drug = requests.get(f"{CPIC}/drug", params={"name": "eq.clopidogrel"}).json()[0]
recs = requests.get(f"{CPIC}/recommendation",
params={"drugid": f"eq.{drug['drugid']}",
"phenotypes": 'cs.{"CYP2C19":"Poor Metabolizer"}'}).json()
print(f"clopidogrel CYP2C19=PM: {len(recs)} recommendation(s)")
for rec in recs[:2]:
print(f" [{rec['classification']}] {rec['drugrecommendation'][:80]}…")
# ClinPGx side: how many CPIC guideline annotations cover CYP2C19?
glines = requests.get(f"{CLINPGX}/data/guidelineAnnotation",
params={"relatedGenes.symbol": "CYP2C19",
"source": "CPIC", "view": "base"}).json()["data"]
print(f"CYP2C19 CPIC guidelines: {len(glines)}")
POST /site/search with a JSON body {"query": "<term>"} is the canonical entry point when you don't know the PA ID. It searches across drugs, genes, variants, clinical annotations, guideline annotations, and labels in one shot.
import requests
CLINPGX = "https://api.clinpgx.org/v1"
r = requests.post(f"{CLINPGX}/site/search",
json={"query": "rs4149056"}, timeout=15)
r.raise_for_status()
hits = r.json()["data"]["hits"]
print(f"Total hits: {r.json()['data']['total']}")
for h in hits[:5]:
print(f" id={h.get('id')} name={h.get('name')[:80]}")
# Broader concept search
r = requests.post(f"{CLINPGX}/site/search",
json={"query": "TPMT azathioprine"}, timeout=15)
hits = r.json()["data"]["hits"]
print(f"TPMT+azathioprine hits: {len(hits)}")
for h in hits[:5]:
print(f" {h.get('id'):>15} {h.get('name','')[:80]}")
The /data/{type} endpoints accept simple property filters. All return {"data": [...], "status": "success"} — use view=base for summary, view=max for full nested objects.
import requests
CLINPGX = "https://api.clinpgx.org/v1"
# Gene by HGNC symbol
gene = requests.get(f"{CLINPGX}/data/gene",
params={"symbol": "CYP2D6", "view": "base"}).json()["data"][0]
print(f"{gene['symbol']} id={gene['id']} {gene['name']}")
# Drug by name (lowercase generic preferred)
drug = requests.get(f"{CLINPGX}/data/drug",
params={"name": "warfarin", "view": "base"}).json()["data"][0]
print(f"{drug['name']} id={drug['id']}")
# Variant by rsID
var = requests.get(f"{CLINPGX}/data/variant",
params={"name": "rs4149056", "view": "base"}).json()["data"][0]
print(f"{var['name']} id={var['id']} significance={var.get('clinicalSignificance')}")
# Direct record fetch when you already have a PA ID
r = requests.get(f"{CLINPGX}/data/drug/PA449088", params={"view": "max"}).json()
d = r["data"]
print(f"PA449088 → {d['name']} (objCls={d['objCls']})")
data/clinicalAnnotation records associate a variant (location) with one or more drugs (relatedChemicals) and an evidence level (levelOfEvidence.term). The two supported filters are relatedChemicals.name= and levelOfEvidence.term=. There is no working gene= filter on this endpoint — see Module 4 for gene-driven access.
import requests, pandas as pd
CLINPGX = "https://api.clinpgx.org/v1"
# All clinical annotations for clopidogrel
data = requests.get(f"{CLINPGX}/data/clinicalAnnotation",
params={"relatedChemicals.name": "clopidogrel",
"view": "base"}).json()["data"]
print(f"clopidogrel annotations: {len(data)}")
rows = []
for ann in data[:10]:
loc = ann.get("location") or {}
drugs = ", ".join(c.get("name", "") for c in ann.get("relatedChemicals", []))
rows.append({
"id": ann["id"],
"variant": loc.get("displayName"),
"gene": (loc.get("genes") or [{}])[0].get("symbol"),
"drug": drugs,
"level": (ann.get("levelOfEvidence") or {}).get("term"),
"score": ann.get("score"),
})
print(pd.DataFrame(rows).to_string(index=False))
# All Level 1A clinical annotations (highest evidence)
data = requests.get(f"{CLINPGX}/data/clinicalAnnotation",
params={"levelOfEvidence.term": "1A",
"view": "base"}).json()["data"]
print(f"Level 1A annotations: {len(data)}")
drug_to_count = {}
for ann in data:
for c in ann.get("relatedChemicals") or []:
drug_to_count[c["name"]] = drug_to_count.get(c["name"], 0) + 1
top = sorted(drug_to_count.items(), key=lambda x: -x[1])[:10]
for d, n in top:
print(f" {n:3} {d}")
data/guidelineAnnotation supports both relatedGenes.symbol= and relatedChemicals.name=, plus source= (CPIC, DPWG, CPNDS, RNPGx). This is the canonical way to get gene→guideline coverage.
import requests
CLINPGX = "https://api.clinpgx.org/v1"
# All CPIC guidelines mentioning CYP2C19
data = requests.get(f"{CLINPGX}/data/guidelineAnnotation",
params={"relatedGenes.symbol": "CYP2C19",
"source": "CPIC",
"view": "base"}).json()["data"]
print(f"CYP2C19 CPIC guidelines: {len(data)}")
for g in data[:5]:
print(f" PA{g['id']}: {g['name'][:80]}")
# Guidelines for a specific drug across all bodies (CPIC, DPWG, …)
data = requests.get(f"{CLINPGX}/data/guidelineAnnotation",
params={"relatedChemicals.name": "clopidogrel",
"view": "base"}).json()["data"]
by_source = {}
for g in data:
for s in (g.get("crossReferences") or []):
by_source.setdefault(s.get("resource", "?"), 0)
by_source[s["resource"]] = by_source.get(s["resource"], 0) + 1
print(f"clopidogrel guidelines: {len(data)} ({list({g.get('source') for g in data})})")
data/label records are PharmGKB-curated annotations of FDA/EMA pharmacogenomic labeling. Filter by relatedChemicals.name= and source= (FDA, EMA, HCSC, PMDA, Swissmedic).
import requests, pandas as pd
CLINPGX = "https://api.clinpgx.org/v1"
data = requests.get(f"{CLINPGX}/data/label",
params={"relatedChemicals.name": "warfarin",
"source": "FDA",
"view": "base"}).json()["data"]
print(f"warfarin FDA labels: {len(data)}")
rows = [{
"name": d["name"][:60],
"biomarker_status": d.get("biomarkerStatus"),
"testing_required": d.get("testingRequired"),
"alternate_drug": d.get("alternateDrugAvailable"),
} for d in data]
print(pd.DataFrame(rows).to_string(index=False))
CPIC's PostgREST API uses column=eq.value for equality and column=cs.{...} for JSONB containment. The standard lookup chain is drug → drugid → recommendation, optionally filtered by phenotype.
import requests
CPIC = "https://api.cpicpgx.org/v1"
# Resolve drug name to drugid (RxNorm-prefixed)
drug = requests.get(f"{CPIC}/drug",
params={"name": "eq.clopidogrel"}).json()[0]
print(f"clopidogrel drugid: {drug['drugid']}")
# All phenotype-specific recommendations for clopidogrel
recs = requests.get(f"{CPIC}/recommendation",
params={"drugid": f"eq.{drug['drugid']}"}).json()
print(f"Total recommendations: {len(recs)}")
for rec in recs[:3]:
print(f" {rec['phenotypes']} [{rec['classification']}]")
print(f" {rec['drugrecommendation'][:90]}…")
# Phenotype filter via jsonb containment (cs.{...})
# The phenotypes column is a jsonb dict; cs. checks that the query is a subset.
recs = requests.get(f"{CPIC}/recommendation",
params={"drugid": f"eq.{drug['drugid']}",
"phenotypes": 'cs.{"CYP2C19":"Poor Metabolizer"}'}
).json()
for rec in recs:
print(f" [{rec['classification']}] {rec['drugrecommendation'][:90]}…")
# Gene-driven: list every drug with a CPIC pair for CYP2C19
pairs = requests.get(f"{CPIC}/pair",
params={"genesymbol": "eq.CYP2C19"}).json()
print(f"\nCYP2C19 CPIC pairs: {len(pairs)}")
drug_ids = sorted({p["drugid"] for p in pairs})
print(f"Sample drug IDs: {drug_ids[:5]}")
| Question | Use | Why |
| ----------------------------------------------- | ----------------------------------- | -------------------------------------------------------------------------------- |
| What clinical annotations exist for this drug? | ClinPGx data/clinicalAnnotation | Annotation-level evidence with curated levelOfEvidence.term |
| What CPIC guidelines cover this gene? | ClinPGx data/guidelineAnnotation | Filter by relatedGenes.symbol; no working gene= filter on clinicalAnnotation |
| Given phenotype X, what should I prescribe? | CPIC recommendation + phenotypes| Structured genotype→action rows; CPIC is the prescribing-rule oracle |
| What FDA labels mention this drug + gene? | ClinPGx data/label?source=FDA | Curated regulatory PGx labeling |
| Free-text "anything about X" | ClinPGx POST /site/search | Cross-record-type fan-out |
Levels 1A → 4 in decreasing evidence quality:
Filter via levelOfEvidence.term on data/clinicalAnnotation. The term is a string, not an enum ("1A" not 1A).
Every ClinPGx /data/... response is {"data": [...] | {...}, "status": "success" | "fail"}. On failure the body is {"status": "fail", "data": {"errors": [{"message": "..."}]}} — always read both keys.
view=base (default) — flat summary record; recommended for bulk filtersview=max — full nested objects (relatedDiseases, allelePhenotypes, scoreDetails, …). Larger payload, slower; use only for single-record details.Goal: Given a patient's pharmacogene panel, count how many CPIC guideline annotations cover each gene.
import requests, pandas as pd, time
CLINPGX = "https://api.clinpgx.org/v1"
pharmacogenes = ["CYP2D6", "CYP2C19", "CYP2C9", "DPYD", "TPMT", "SLCO1B1"]
rows = []
for g in pharmacogenes:
data = requests.get(f"{CLINPGX}/data/guidelineAnnotation",
params={"relatedGenes.symbol": g,
"source": "CPIC", "view": "base"},
timeout=20).json()["data"]
drugs = sorted({c["name"] for guideline in data
for c in (guideline.get("relatedChemicals") or [])})
rows.append({"gene": g, "cpic_guidelines": len(data),
"n_drugs": len(drugs), "sample": ", ".join(drugs[:3])})
time.sleep(0.3)
df = pd.DataFrame(rows).sort_values("cpic_guidelines", ascending=False)
print(df.to_string(index=False))
df.to_csv("pharmacogene_cpic_coverage.csv", index=False)
Goal: Given a prescribed drug list, identify which have CPIC genotype-specific recommendations and surface the rule rows.
import requests, pandas as pd, time
CPIC = "https://api.cpicpgx.org/v1"
drugs = ["warfarin", "clopidogrel", "codeine", "simvastatin",
"metoprolol", "omeprazole", "azathioprine", "tacrolimus"]
rows = []
for name in drugs:
drug = requests.get(f"{CPIC}/drug", params={"name": f"eq.{name}"}, timeout=15).json()
if not drug:
rows.append({"drug": name, "in_cpic": False, "n_recs": 0, "phenotypes": ""}); continue
did = drug[0]["drugid"]
recs = requests.get(f"{CPIC}/recommendation",
params={"drugid": f"eq.{did}"}, timeout=15).json()
phens = sorted({f"{k}={v}" for rec in recs
for k, v in (rec.get("phenotypes") or {}).items()})
rows.append({"drug": name, "in_cpic": True, "n_recs": len(recs),
"phenotypes": "; ".join(phens[:3])})
time.sleep(0.3)
df = pd.DataFrame(rows).sort_values(["in_cpic", "n_recs"], ascending=[False, False])
print(df.to_string(index=False))
Goal: Starting from a single rsID (e.g., SLCO1B1 *5 = rs4149056), find every clinical annotation that involves it.
The Data API does not accept rsID as a filter property. Use POST /site/search to discover related annotation IDs, then fetch each by ID.
import requests
CLINPGX = "https://api.clinpgx.org/v1"
rsid = "rs4149056"
hits = requests.post(f"{CLINPGX}/site/search",
json={"query": rsid}, timeout=15).json()["data"]["hits"]
print(f"{rsid}: {len(hits)} hits")
# Filter hits that look like clinical annotations
ann_hits = [h for h in hits if h.get("name", "").lower().startswith("clinical annotation")]
print(f"Clinical-annotation hits: {len(ann_hits)}")
for h in ann_hits[:5]:
print(f" id={h['id']} {h['name'][:90]}")
# Dereference one annotation by ID for full detail
if ann_hits:
ann = requests.get(f"{CLINPGX}/data/clinicalAnnotation/{ann_hits[0]['id']}",
params={"view": "max"}, timeout=15).json()["data"]
drugs = ", ".join(c["name"] for c in (ann.get("relatedChemicals") or []))
print(f"\nFirst annotation:")
print(f" drugs: {drugs}")
print(f" level: {(ann.get('levelOfEvidence') or {}).get('term')}")
| Parameter | Module / Endpoint | Default | Range / Options | Effect |
| --------------------------- | ---------------------------------------------- | ------- | -------------------------------------------------------- | ----------------------------------------------------------------------- |
| view | all /data/... | base | base, min, max | Field detail level; max includes all nested arrays (slow but complete) |
| relatedChemicals.name | clinicalAnnotation, variantAnnotation, guidelineAnnotation, label, pathway | — | lowercase generic drug name | Filter records related to a drug |
| relatedGenes.symbol | guidelineAnnotation, pathway | — | HGNC gene symbol | Filter records related to a gene (not available on clinicalAnnotation) |
| levelOfEvidence.term | clinicalAnnotation | — | "1A", "1B", "2A", "2B", "3", "4" | Minimum evidence level |
| source | guidelineAnnotation, label | — | CPIC, DPWG, FDA, EMA, HCSC, PMDA, Swissmedic | Issuing body |
| symbol | data/gene | — | HGNC gene symbol | Gene record lookup |
| name | data/drug, data/variant | — | drug name or rsID | Record lookup by canonical name |
| CPIC column=eq.value | all api.cpicpgx.org/v1/... | — | PostgREST equality | Filter by exact match |
| CPIC phenotypes=cs.{json} | recommendation | — | JSON-encoded jsonb subset | Filter by phenotype containment (must URL-encode if special chars) |
Resolve PA identifiers once. Never hand-construct ClinPGx PA IDs. Call data/{type}?{symbol|name}=... (or site/search) once and cache the returned id for reuse — gene/PA128 for CYP2D6, drug/PA449088 for clopidogrel, variant/PA166154579 for rs4149056.
Pick the right host for the question. Use ClinPGx for what is annotated and CPIC for what to prescribe. Trying to derive genotype-specific recommendations from ClinPGx alone misses the structured recommendation.phenotypes rows.
Filter by evidence level upfront when building clinical workflows. levelOfEvidence.term=1A returns 312 actionable annotations across all of ClinPGx; Level 3/4 records are exploratory and shouldn't drive prescribing.
Don't filter clinicalAnnotation by gene — filter by guidelineAnnotation with relatedGenes.symbol. The clinicalAnnotation endpoint has no working gene property and returns HTTP 400 for any attempt.
Use view=base for bulk filters, view=max for single-record drill-downs. A list query with view=max can time out or hit 429; the difference is roughly 5–10× payload size.
Throttle the ClinPGx host. Insert time.sleep(0.3) between sequential queries in loops; the API returns occasional HTTP 429s on tight loops. CPIC tolerates faster iteration.
URL-encode cs.{...} jsonb filters when phenotype values contain spaces or special characters. requests.get(..., params={"phenotypes": 'cs.{"CYP2C19":"Poor Metabolizer"}'}) works because requests does the encoding; a manual URL string needs urllib.parse.quote.
When to use: you have an arbitrary string (rsID, drug name, gene, allele) and want to find related ClinPGx records without knowing which endpoint to hit.
import requests
r = requests.post("https://api.clinpgx.org/v1/site/search",
json={"query": "VKORC1 warfarin"}, timeout=15)
hits = r.json()["data"]["hits"]
for h in hits[:10]:
print(f" {h.get('id'):>15} {h.get('name','')[:80]}")
When to use: build a leaderboard of the most actionable PGx drugs.
import requests, pandas as pd
data = requests.get("https://api.clinpgx.org/v1/data/clinicalAnnotation",
params={"levelOfEvidence.term": "1A", "view": "base"},
timeout=30).json()["data"]
counts = {}
for ann in data:
for c in ann.get("relatedChemicals") or []:
counts[c["name"]] = counts.get(c["name"], 0) + 1
df = pd.DataFrame(sorted(counts.items(), key=lambda x: -x[1]),
columns=["drug", "n_1A_annotations"]).head(15)
print(df.to_string(index=False))
When to use: given a phenotype call from a PGx test, surface every CPIC recommendation row.
import requests
CPIC = "https://api.cpicpgx.org/v1"
genotype = {"CYP2C19": "Poor Metabolizer"}
drug = "clopidogrel"
did = requests.get(f"{CPIC}/drug", params={"name": f"eq.{drug}"}).json()[0]["drugid"]
import json
recs = requests.get(f"{CPIC}/recommendation",
params={"drugid": f"eq.{did}",
"phenotypes": f"cs.{json.dumps(genotype)}"}).json()
for rec in recs:
print(f"[{rec['classification']}] {rec['drugrecommendation']}")
print(f" implications: {rec['implications']}")
When to use: long-running loops over many genes / drugs / variants.
import requests
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry
s = requests.Session()
s.headers.update({"Accept": "application/json"})
s.mount("https://", HTTPAdapter(max_retries=Retry(
total=4, backoff_factor=1.0,
status_forcelist=[429, 500, 502, 503, 504],
allowed_methods=["GET", "POST"])))
r = s.get("https://api.clinpgx.org/v1/data/gene",
params={"symbol": "CYP2D6", "view": "base"}, timeout=20)
r.raise_for_status()
print(r.json()["data"][0]["name"])
| Problem | Cause | Solution |
| ----------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------- |
| HTTP 404/405 on https://api.pharmgkb.org/v1/... | Old PharmGKB host is dead; the service rebranded to ClinPGx in 2024 | Migrate to https://api.clinpgx.org/v1/.... Old /clinicalAnnotation?gene=X is now data/clinicalAnnotation with different filters. |
| {"status":"fail","data":{"errors":[{"message":"No such property: 'gene'"}]}} | data/clinicalAnnotation does not accept gene= or relatedGenes.symbol= | Use data/guidelineAnnotation?relatedGenes.symbol=X for gene-driven access, or ?relatedChemicals.name=Y for drug-driven. |
| {"status":"fail","data":{"errors":[{"message":"Missing criteria."}]}} | A data/{type} list query has no filter and no ID | Add at least one filter (name=, symbol=, relatedChemicals.name=, …) or fetch by ID via data/{type}/{paId}. |
| HTTP 405 on GET /site/search?query=... | site/search only accepts POST with a JSON body | Use requests.post(url, json={"query": "..."}). |
| HTTP 429 mid-loop | Hit ClinPGx rate limit | Insert time.sleep(0.3–0.5) between calls; use the Retry session in Recipe 4. |
| HTTP 400 on https://api.cpicpgx.org/v1/recommendation?phenotypes=cs.{...} | The cs. JSON wasn't URL-encoded | Pass via requests params={"phenotypes": 'cs.{"CYP2C19":"Poor Metabolizer"}'} (auto-encoded) or urllib.parse.quote manually. |
| Empty data list for an obviously-real drug | Drug name mismatch (brand vs. generic; capitalization) | Try lowercase generic name; fall back to POST /site/search to fan out and find the canonical PA ID. |
| data/variant?name=rs... returns 1 record but data/clinicalAnnotation?location.name=rs... returns 404 | rsID is stored under location.displayName/location.rsid, not exposed as a filterable property | Use site/search to discover annotation IDs by rsID, then dereference each with data/clinicalAnnotation/{id}. (Workflow 3.) |
clinvar-database — germline pathogenicity / clinical significance for variants found in PharmGKB (complementary; ClinVar is disease-focused, ClinPGx is drug-response-focused)opentargets-database — drug-target associations and safety signals overlapping ClinPGx pharmacogene targetschembl-database-bioactivity — bioactivity and binding data for the drugs annotated in ClinPGxcosmic-database — somatic cancer mutations and tumor-specific PGx (orthogonal to germline PGx covered here)data/{type}/{paId} URL shapedata/... and site/search schemasrecommendation rows; canonical genotype-prescribing oracletools
Fast short-read DNA aligner for WGS/WES/ChIP-seq. 2× faster BWA-MEM successor; outputs SAM/BAM with read group headers for GATK. Primary plus supplementary records for chimeric reads. Use STAR for RNA-seq splice-aware alignment; Bowtie2 is a comparable alternative.
tools
smina molecular docking CLI. AutoDock Vina fork with customizable scoring functions, native SDF/MOL2/PDB ligand input, autoboxing, local energy minimization, and per-atom score breakdowns. Pipeline: receptor PDBQT prep -> ligand prep (RDKit/OpenBabel) -> dock via autobox or explicit grid -> rescore/minimize with custom scoring -> rank poses by affinity. Choose smina over Vina when you need custom scoring terms (--custom_scoring), local optimization of an existing pose (--local_only), per-atom contributions (--atom_term_data), or SDF/MOL2 ligands without manual PDBQT conversion. For unknown binding sites use diffdock-blind-docking; for the Python-bindings/Vinardo workflow use autodock-vina-docking.
development
mdtraj molecular dynamics trajectory analysis (Python). Reads DCD/XTC/TRR/NetCDF/H5/PDB topologies and trajectories; computes RMSD vs time, radius of gyration, per-residue RMSF, residue-residue contact frequency maps, phi/psi torsions for Ramachandran plots (general + Gly/Pro), and 8-state DSSP secondary structure. Modules: trajectory I/O, geometry (distances/angles/dihedrals), structural analysis (RMSD/Rg/RMSF/SASA), contacts, hydrogen bonds, secondary structure (DSSP), NMR observables. For broader atom-selection grammar use mdanalysis-trajectory; for running MD simulations use OpenMM/GROMACS.
development
Programmatic PubMed access via NCBI E-utilities REST API. Covers Boolean/MeSH queries, field-tagged search, endpoints (ESearch, EFetch, ESummary, EPost, ELink), history server for batches, citation matching, systematic review strategies. Use for biomedical literature search or automated pipelines.