A facility for providing document contents from a server is described. The facility receives from a separate client computing system a retrieval request to return a document identified by a document identifier contained by the retrieval request. The retrieval request has been originated by the client computing system in response to an open request for a file stored on the client computing system that contains the document identifier. The facility transmits to the client a response containing at least a portion of a document to which the document identifier contained by the retrieval request corresponds.