hpo-link
hpo-link is a read-only MCP server that grounds phenotype questions in HPO terms, hierarchy, mappings, and gene–phenotype–disease annotations from a local HPO/HPOA index.
Resolve free-text labels, synonyms, HP IDs, and external CURIEs to canonical HPO terms, and full-text search term names, synonyms, and definitions.
Retrieve HPO term records and navigate the
is_ahierarchy via direct/transitive parents, ancestors, children, and descendants.Map HPO terms to external ontologies/vocabularies such as UMLS, SNOMEDCT_US, ORPHA, MONDO, and ICD, and resolve external CURIEs back to HP terms.
Query HPOA associations: phenotypes for genes or diseases, genes or diseases for phenotypes, genes for diseases, and diseases for genes.
Expand phenotype association queries to include descendant terms when needed.
Discover server capabilities and diagnostics, including loaded HPO release, index counts, and runtime health.
Use response modes, pagination, and
next_commandsfor token-efficient follow-up workflows.
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@hpo-link find phenotypes for gene BRCA1"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
hpo-link
An MCP server (Streamable HTTP or stdio) that grounds phenotype work in the
Human Phenotype Ontology (HPO): term lookup, the is_a
hierarchy, cross-ontology mapping, and gene↔phenotype↔disease associations, served
read-only from a local index of the HPO release and its HPOA annotations.
Research use only. Not clinical decision support. Do not use for diagnosis, treatment, triage, or patient management.
Why
HPO ships as bulk artifacts — an OBO/JSON ontology graph (hp.json) and a flat
annotation table (phenotype.hpoa). Neither answers a question. "Which genes are
annotated to seizure, including its subtypes?" needs the transitive is_a closure over
a multi-parent DAG, a synonym/xref index to get from free text to HP:0001250, and a
join against HPOA — plumbing every consumer otherwise rebuilds, badly.
hpo-link builds that once into a read-only SQLite index (closure table, FTS over
names/synonyms/definitions, xrefs ranked by mapping predicate) and serves it as MCP
tools. No upstream call sits in the request path, so lookups are offline and
deterministic, and every response cites the HPO id and the HPO release it came from.
Related MCP server: Unofficial HPO MCP Server
Quick start
Hosted — no install:
claude mcp add --transport http hpo-link https://hpo-link.genefoundry.org/mcpLocal (Python 3.14+, uv):
uv sync --group dev # install
make data # REQUIRED: download HPO + HPOA and build the local database
make data-status # loaded HPO release + counts
make dev # unified REST + MCP on http://127.0.0.1:8000 (/mcp, /health)There is no data until make data (uv run hpo-link-data build) has run once.
claude mcp add --transport http hpo-link --scope user http://127.0.0.1:8000/mcp
make mcp-serve # stdio instead, for Claude Desktop (stdout is the protocol)Three console scripts: hpo-link (unified server), hpo-link-mcp (stdio),
hpo-link-data (build / refresh / status for data authoring, and
materialize-data for the hardened deployment init sidecar).
Tools
Tool | Purpose |
| Discovery surface — tools, workflows, error taxonomy, limits |
| Database status, loaded HPO release, counts |
| Label, synonym, HP id or xref → one canonical term + |
| Full-text search over names, synonyms and definitions |
| The record — definition, synonyms, grouped xrefs, parents/children, obsolescence |
| Transitive |
| Transitive |
| Direct |
| Direct |
| External CURIE ( |
| An HP term → its mappings, grouped by target prefix |
| HPO terms annotated to a gene |
| Genes annotated to an HPO term |
| HPO terms annotated to a disease |
| Diseases annotated to an HPO term |
| Genes associated with a disease |
| Diseases associated with a gene |
Every response carries _meta.next_commands (ready-to-call follow-ups). Ids are
normalised to HP:NNNNNNN. response_mode ∈ minimal | compact | standard | full
(default compact) trades detail for tokens. Worked examples: docs/usage.md.
Leaf names are unprefixed per
Tool-Naming Standard v1
(serverInfo.name = hpo-link); behind
genefoundry-router the gateway applies
the canonical namespace token hpo, so they surface as hpo_<tool> — e.g.
hpo_resolve_term.
Data & provenance
Built from two upstream artifacts: the HPO ontology (hp.json, via the OBO PURL
http://purl.obolibrary.org/obo/hp.json) and the HPOA annotations
(phenotype.hpoa), which link HPO terms to OMIM / Orphanet / DECIPHER diseases and,
derived from those, to genes.
Local data authoring can refresh from upstream with conditional GET (ETag /
Last-Modified), but deployed servers do not. Production uses the immutable,
digest-pinned release declared in container-release.json: hpo-data-init
materializes it before the application starts, then the application reads the
selected snapshot only. Details: docs/data.md.
Data licence: HPO is distributed under a custom licence for research and educational use (https://hpo.jax.org/app/license) — attribution required.
Cite: Köhler S, Gargano M, Matentzoglu N, et al. The Human Phenotype Ontology in 2021. Nucleic Acids Research 2021;49(D1):D1207–D1217. doi:10.1093/nar/gkaa1043. For the most recent release cite instead: Gargano MA, Matentzoglu N, Coleman B, et al. The Human Phenotype Ontology in 2024: phenotypes around the world. Nucleic Acids Research 2024;52(D1):D1333–D1346. doi:10.1093/nar/gkad1005.
Documentation
Usage — per-tool examples, the citation contract, typical workflows.
Architecture — the two planes, ingest pipeline, SQLite schema, request lifecycle.
Data & provenance — sources, freshness, build integrity, prebuilt artifacts, licence.
Configuration — every
HPO_LINK_*variable and the Host/Origin/CORS allowlists.Deployment — Docker init sidecar, health and deploy verification.
AGENTS.md — engineering conventions, invariants, definition of done.
Contributing
See AGENTS.md for the invariants and conventions. make ci-local is the
definition-of-done gate: format, lint, line budget, README standard, mypy, and tests.
Write the failing test first.
License
MIT © Bernt Popp — code only. The HPO data is licensed separately for research and educational use with required attribution (https://hpo.jax.org/app/license); see Data & provenance.
Available Tools
17 toolsget_diagnosticsGet HPO DiagnosticsARead-onlyIdempotent
Report the local HPO index status: whether the data is built, the loaded HPO and HPOA release versions, term/obsolete/closure/xref/annotation counts, when it was built, and a runtime block (request/error counts and latency percentiles p50/p95/p99). Use this to confirm freshness or diagnose an upstream_unavailable error (an unbuilt/unavailable local index). Signature: get_diagnostics().
Inputs: no named parameters.
get_diseases_for_geneGet Diseases for GeneBRead-onlyIdempotent
Return diseases associated with a gene (symbol or NCBI id). Signature: get_diseases_for_gene(gene, limit=, offset=, response_mode=).
Inputs: gene (required), limit, offset, response_mode.
get_diseases_for_phenotypeGet Diseases for HPO PhenotypeARead-onlyIdempotent
Return diseases annotated to an HPO phenotype term, optionally expanded to include descendants. Signature: get_diseases_for_phenotype(hpo_id, include_descendants=, limit=, offset=, response_mode=).
Inputs: hpo_id (required), limit, offset, response_mode, +1 more.
get_genes_for_diseaseGet Genes for DiseaseARead-onlyIdempotent
Return genes associated with a disease CURIE (e.g. OMIM:106210, ORPHA:550). Signature: get_genes_for_disease(disease_id, limit=, offset=, response_mode=).
Inputs: disease_id (required), limit, offset, response_mode.
get_genes_for_phenotypeGet Genes for HPO PhenotypeARead-onlyIdempotent
Return the genes annotated to an HPO phenotype term, optionally expanded to include descendants. Signature: get_genes_for_phenotype(hpo_id, include_descendants=, limit=, offset=, response_mode=).
Inputs: hpo_id (required), limit, offset, response_mode, +1 more.
get_phenotypes_for_diseaseGet HPO Phenotypes for DiseaseARead-onlyIdempotent
Return the HPO phenotype terms annotated to a disease CURIE (e.g. OMIM:106210, ORPHA:550). Signature: get_phenotypes_for_disease(disease_id, limit=, offset=, response_mode=).
Inputs: disease_id (required), limit, offset, response_mode.
get_phenotypes_for_geneGet HPO Phenotypes for GeneARead-onlyIdempotent
Return the HPO phenotype terms annotated to a gene (symbol or NCBI id). Signature: get_phenotypes_for_gene(gene, limit=, offset=, response_mode=).
Inputs: gene (required), limit, offset, response_mode.
get_server_capabilitiesGet Server CapabilitiesARead-onlyIdempotent
Return the hpo-link discovery surface: identity/build/HPO release, the tool list WITH call signatures, response modes, recommended workflows, the xref prefixes, the error taxonomy, and limits. detail='full' adds the full policy notes. Call this first in a cold session, or read hpo://tools / hpo://capabilities. Signature: get_server_capabilities(detail=).
Inputs: detail.
get_termGet HPO TermARead-onlyIdempotent
Return an HPO phenotype term record: definition, synonyms (exact/related/broad/narrow), alt_ids, subsets, comments, cross-references, direct parents and children, and obsolescence (replaced_by). The term accepts an HP id, a label/synonym, or an external xref CURIE (resolved first). Pass fields=['synonyms', 'definition'] for a sparse projection. Note on synonyms shape: compact (default) returns synonyms as plain strings; standard/full return {text, scope} objects. Signature: get_term(hpo_id, response_mode=, fields=).
Inputs: hpo_id (required), fields, response_mode.
get_term_ancestorsGet HPO Term AncestorsARead-onlyIdempotent
Return all transitive is_a ancestors (broader phenotype terms) of an HPO term via the precomputed closure, with a pagination block {total, returned, limit, offset, truncated, next_offset}. When truncated, next_commands carries a forward-page step (offset) so you can walk a >limit closure without re-sending rows. Use get_term_parents for only the immediate parents. Signature: get_term_ancestors(hpo_id, limit=, offset=, response_mode=).
Inputs: hpo_id (required), limit, offset, response_mode.
get_term_childrenGet HPO Term ChildrenARead-onlyIdempotent
Return the direct is_a children (immediate more-specific phenotype terms) of an HPO term. Use get_term_descendants for the full transitive set. Signature: get_term_children(hpo_id, response_mode=).
Inputs: hpo_id (required), response_mode.
get_term_descendantsGet HPO Term DescendantsARead-onlyIdempotent
Return all transitive is_a descendants (more specific phenotype terms) of an HPO term via the precomputed closure, with a pagination block {total, returned, limit, offset, truncated, next_offset}. When truncated, next_commands carries a forward-page step (offset) so you can walk a >limit closure without re-sending rows. Use get_term_children for only the immediate children. Signature: get_term_descendants(hpo_id, limit=, offset=, response_mode=).
Inputs: hpo_id (required), limit, offset, response_mode.
get_term_parentsGet HPO Term ParentsARead-onlyIdempotent
Return the direct is_a parents (immediate broader phenotype terms) of an HPO term. Use get_term_ancestors for the full transitive set. Signature: get_term_parents(hpo_id, response_mode=).
Inputs: hpo_id (required), response_mode.
map_cross_ontologyMap HPO Cross-OntologyARead-onlyIdempotent
List an HPO term's cross-references to other ontologies/vocabularies, grouped by target prefix (UMLS/SNOMEDCT_US/NCIT/MEDDRA/ICD-10/ICD-9/MONDO/DOID/ORPHA/EFO/MSH/MESH). Optionally restrict to a subset of prefixes. Signature: map_cross_ontology(hpo_id, prefixes=, response_mode=, fields=).
Inputs: hpo_id (required), fields, prefixes, response_mode.
resolve_termResolve HPO TermARead-onlyIdempotent
Resolve a phenotype label, synonym, HP id (HP:0000118), or external cross-reference CURIE (UMLS:C0000737, SNOMEDCT_US:263681008, ...) to the canonical HPO term {hpo_id, name, match_type}. An ambiguous label returns ambiguous_query with candidates (each {hpo_id, name}); an obsolete HP id resolves with success:true, obsolete:true, and its successor in replaced_by. This is the recommended first step — resolve any query to a canonical HP id before calling get_term. Signature: resolve_term(query, response_mode=).
Inputs: query (required), response_mode.
resolve_xrefResolve HPO Cross-ReferenceARead-onlyIdempotent
Resolve an external cross-reference CURIE (UMLS/SNOMEDCT_US/NCIT/MEDDRA/ICD-10/ICD-9/MONDO/DOID/ORPHA) back to the HPO term(s) that cross-reference it. Returns matches[] plus a pagination block {total, returned, limit, offset, truncated, next_offset}; when truncated, next_commands carries a forward-page step (offset). Signature: resolve_xref(xref_id, limit=, offset=, response_mode=).
Inputs: xref_id (required), limit, offset, response_mode.
search_termsSearch HPO TermsARead-onlyIdempotent
Full-text search over HPO phenotype term names, synonyms, and definitions (FTS, relevance-ranked). Returns {hpo_id, name, score} -- compact adds a short definition_snippet; standard/full add the complete definition -- plus a pagination block {total, returned, limit, offset, truncated, next_offset}. When truncated, next_commands carries a forward-page step (offset advanced) and a widen step. Obsolete terms are excluded unless include_obsolete=true. Signature: search_terms(query, limit=, offset=, include_obsolete=, response_mode=).
Inputs: query (required), limit, offset, response_mode, +1 more.
Tool Schema Changelog
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TDQS
Scored across 17 tools
Most tools have crisp boundaries: direct vs transitive hierarchy (parents/ancestors, children/descendants) is explicitly contrasted in descriptions, and the inverse-direction pairs (get_genes_for_disease / get_diseases_for_gene, etc.) are unambiguous. The one soft overlap is resolve_xref vs resolve_term (which also accepts xref CURIEs) and map_cross_ontology, though descriptions disambiguate them adequately.
Uniform snake_case with a consistent verb_noun convention throughout (get_term, get_term_ancestors, resolve_term, search_terms, map_cross_ontology). The relationship queries all follow the same 'get_X_for_Y' pattern, making the set highly predictable.
17 tools is well-matched to a knowledge base spanning ontology navigation plus the gene/phenotype/disease annotation triangle. Each tool covers a distinct axis (resolution, search, hierarchy, cross-refs, annotation cross-products), so none feel redundant.
Strong coverage of term resolution, hierarchy traversal in both directions (direct and transitive), cross-refs both ways, and all six gene/phenotype/disease annotation directions. Minor gap: no direct record lookup for a disease or gene entity (metadata), and no annotation evidence/detail access, but core workflows are covered.
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