Search PubMed with MeSH support, structured filters, pagination, and selectable output verbosity. output_mode=minimal returns id/title/url/full_text_available only (legacy-compatible); compact (default) adds authors/journal/year/doi/pmcid; full additionally includes abstract/mesh_terms/publication_types.

Retrieve abstract for a single PMID (OpenAI MCP compliant). Accepts exactly one PMID. For multiple PMIDs, use fetch_batch.

Retrieve abstracts for multiple PMIDs in a single batch request. Returns structured data per PMID. Set include_abstract=false to omit the abstract field (e.g., when you only need full author lists).

Retrieve full text of articles from PubMed Central (PMC) by PMC ID. Supports section filtering to reduce token usage.

Get only the count of search results for query adjustment and optimization. Fast — retrieves no actual data. Useful for refining search strategies.

Find similar articles for a given PMID using MeSH terms and title-based similarity. Useful for literature review and related research discovery.

Export PubMed articles to RIS format for citation managers (EndNote/Zotero/Mendeley). Returns compact RIS with minimal metadata — citation managers auto-fetch the rest via PMID.

Get citation counts for PMIDs. Default source is iCite (counts only, includes citations from outside PubMed). Set citing_source='pubmed' for elink-based PubMed-internal citations and to retrieve citing PMIDs (useful for backward snowballing).

Convert between PMID, PMCID, and DOI identifiers using NCBI ID Converter API.

Run multiple operations against the same set of PMIDs in one call. Helpful for systematic-review style workflows. operations is an array drawn from: 'abstract', 'citations', 'similar', 'ris_export', 'full_text'. Respects NCBI rate limits via max_concurrency (default 3).