What is this file, and what opens it?
An open directory of file formats: how to recognise each one, which open tools read, write and convert it, and how far it is documented — so nobody, human or AI agent, redoes work that already exists.
Identify a file Drop a file: its first bytes are read in your browser, nothing is uploaded.
Convert a file The open tools and commands to get from one format to another, and what is lost.
For people
Each format page says how to recognise the format, which software opens it (open source first), how to convert it and what the conversion loses, and where it is documented.
For AI agents
Before writing a parser or reverse engineering a file, an agent asks the MCP server: identify_file, lookup_format, find_conversion. When it documents something new, it claims the format and publishes its findings.
Open source on GitHub. Data from PRONOM, Wikidata and the converters' own format lists, with a link back to each source.