cern-opendata

name

cern-opendata

description

Use when the user has a CERN Open Data `recid`, DOI, or exact record title and needs portal-level metadata, file URIs, container images, or supplementary files across CMS, ATLAS, LHCb, ALICE, or OPERA. Backed by the `cernopendata` MCP at opendata.cern.ch (records, files, glossary). Does NOT cover ATLAS Monte Carlo metadata by DSID or `physics_short` (use `atlas-opendata`), collaboration-internal datasets (use `rucio`), or canonical CERN service / ATLAS-software documentation (use `cern-docs` for SWAN, HTCondor, Cloud, ML@CERN, Athena docs). Disambiguator phrase: opendata.cern.ch recid resolver.

Scope

Use this skill whenever the user is working with the portal itself — browsing, resolving DOIs, fetching record metadata, or listing the files attached to a record. The cernopendata MCP is portal-wide: it does not know about ATLAS DSIDs, physics_short names, k-factors, or filter efficiencies. For those, switch to (or also load) the atlas-opendata skill.

The two skills cooperate. A typical flow is:

1. Use cod_resolve_record / cod_get_metadata to locate a portal record (e.g. an ATLAS analysis example or a CMS primary dataset).
2. Use cod_list_files to get the file URIs attached to that record.
3. If the workflow depends on ATLAS-specific MC metadata (DSID, cross-section, sumOfWeights), load atlas-opendata and use atlas_match_metadata / atlas_get_metadata.

This MCP is read-only: it does not download files. URIs are returned for you to hand off to curl, xrdcp, uproot, coffea, etc.

MCP Tools Available

The cernopendata MCP server provides these tools (all prefixed with cod_):

Records

• cod_get_record — Full JSON for a record (by recid / doi / title)
• cod_get_metadata — Compact projection of the most useful fields; pass field for a single field
• cod_resolve_record — Resolve a DOI or exact title to a numeric recid

Files

• cod_list_files — List data file URIs attached to a record (token-efficient, URIs only)
• cod_get_file_urls — URIs with size and checksum per file (for transfer planning or integrity checks)

Directory (optional XRootD)

• cod_list_directory — Browse the EOSPUBLIC directory tree over XRootD. Requires the [xrootd] extra to be installed server-side; otherwise returns an instructive "not available" recovery message.

MCP Resources

• cernopendata://guide — Overview of experiments, record types, collections, keywords, file-index mechanism, URI protocols.
• cernopendata://record-fields — Reference for the JSON fields returned by the Invenio record API.

Workflow

1. If you have a DOI or exact title but no recid, call cod_resolve_record first.
2. For a compact overview of a record, use cod_get_metadata. Pass field= for a single value.
3. For the full record JSON (all Invenio fields), use cod_get_record.
4. To get file URIs for streaming or download, use cod_list_files (URIs only) or cod_get_file_urls (with sizes and checksums).
5. For large-campaign directory browsing where records point to file-indexes, use cod_list_directory.

Identifiers

Provide exactly one of recid / doi / title to record and file tools. recid accepts an int or a numeric string.

Identifier	Example	Notes
recid	1, 12345	Preferred; stable numeric ID.
doi	10.7483/OPENDATA.CMS.ABCD.1234	Full DOI string.
title	"Higgs-to-four-lepton ..."	Must be exact; no wildcards.

Experiments covered

• ATLAS, CMS, LHCb, ALICE — LHC detectors
• OPERA — earlier SPS neutrino experiment

Record types include Dataset, Simulated Dataset, Derived Dataset, Software, Documentation, Environment, Tool, Configuration, Workflow, Supplementaries.

Protocols

File URIs can be returned in two protocols:

• http (default) — HTTPS download URL, suitable for curl / web download / most batch systems.
• xrootd — root://eospublic.cern.ch//eos/..., suitable for ROOT / uproot / coffea streaming.

File indexes

Record files lists often contain file-index files rather than the data files themselves (a .txt or .json listing the real URIs). cod_list_files and cod_get_file_urls dereference these by default (expand=True). Set expand=False only when you specifically want the raw index entry.

Recovery behaviour

All tools return error strings (never raise). When something fails the response includes a Recovery steps: block naming the concrete tool to call next — follow those suggestions instead of guessing.