PubMed API

Prerequisites

1. uv: Read the uv skill and follow its Setup instructions to ensure uv is installed and on PATH.
2. User Notification: If .licenses/pubmed_database_LICENSE.txt does not already exist in the workspace root directory then (1) prominently notify the user to check the terms at https://pubmed.ncbi.nlm.nih.gov/disclaimer/ and https://www.ncbi.nlm.nih.gov/home/about/policies/ and to always check the license of the papers retrieved by the skill for any restrictions, then (2) create the file recording the notification text and timestamp.
3. .env file: Make sure the .env file exists in your home directory. Create one if it does not exist.
4. NCBI_API_KEY (optional): Raises the NCBI E-utilities rate limit from 3 to 10 requests/second. The skill works without it, but a key is recommended if the user plans many queries or encounters a 429 error. You can register for a key for free at https://www.ncbi.nlm.nih.gov/account/settings/. You MUST use the safe credentials protocol in the credentials skill to check for and request this key if this skill looks relevant to the user's request.
5. USER_EMAIL (optional): Identifies the caller to NCBI (recommended by their Terms of Use). You MUST use the safe credentials protocol in the credentials skill to check for and request this credential if this skill looks relevant to the user's request.

This skill provides CLI access to the NCBI PubMed and PubMed Central APIs via scripts/pubmed_api.py, a single CLI with 10 functions covering search, fetch, linking, full text, spelling, discovery, citation matching, and caching.

Core Rules