available_years
is exhaustive, not a sample: any other year fails with yearnotavailable before a request goes out, naming the years that do work. It is narrower than what the Census API hosts — pep/charv reaches its 2020-2022 estimates through the YEAR filter inside the 2023 vintage, and the cbp/nonemp vintages lef
How to use it
available_years is exposed by the Census MCP Server MCP server. Add the server to your MCP client (Claude Desktop, Cursor, Windsurf and others), and the available_years tool becomes available to the model automatically. See the full listing for setup details and every tool this server provides.
Install Census MCP Server
docker run --rm -e CENSUS_API_KEY=your-key -p 3010:3010 census-mcp-serverOther tools in Census MCP Server (10)
Rank and compare variables across multiple geographies — all counties in a state, all states nationally, or a named set. Sorted table output, with the same predicate filtering.
Fetch full metadata for one or more variable codes — label, concept, predicate type, universe, MOE sibling.
Browse available Census Bureau datasets (ACS5, ACS1, Population Estimates, Decennial, County Business Patterns, Economic Census, Nonemployer Statistics) with vintage years and dataset codes.
List the geography levels supported by a dataset and year, with parent requirements and example FIPS values.
List the codes a filter dimension accepts (EMPSZES, LFO, POPGROUP, NAICS2017…), from the dataset dictionary or a live wildcard enumeration.
Query a Census dataset for variables at a specific geography. Returns estimates with MOE, suppression codes resolved to readable reasons, and predicate filtering for the business datasets.
Convert place names (e.g., "King County, WA") or street addresses to Census FIPS identifiers via TIGERweb and Census Geocoder.
Keyword search across variable labels and concept groups. On ACS, returns estimate and margin-of-error codes together.
publishes TAXSTAT and TYPOP per industry, so withinnaics scopes the enumeration — and the notice says the result is complete for that industry alone. A per-industry dimension is left unchecked for the same reason, since an unscoped check would withhold codes a scoped query does return
and countyfips are zero-padded to the widths the Census matches on, so "5" and "05" both find Arkansas; either also takes "", which is what reaches every block group in a state. geographyfips takes its width from geographylevel and is passed through as given