Currently all schema.org pages carry the same <meta> description.

Person - schema.org
http://schema.org/Person
<meta name="description" content="Schema.org is a set of extensible schemas that enables webmasters to embed structured data on their web pages for use by search engines and other applications." />

Thesis - bib.schema.org
https://bib.schema.org/Thesis
<meta name="description" content="Schema.org is a set of extensible schemas that enables webmasters to embed structured data on their web pages for use by search engines and other applications." />

This is not helpful for any data consumer that uses the <meta> description to provide users with a description in things like snippets (most notably search engines and social media networks), as the current boilerplate description does not describe any page specifically.

A better - and probably relatively easy - method of populating the meta description would be to use the item description.

Person - schema.org
http://schema.org/Person
<meta name="description" content="A person (alive, dead, undead, or fictional)." />

inSupportOf - bib.schema.org
https://bib.schema.org/inSupportOf
<meta name="description" content="Qualification, candidature, degree, application that Thesis supports." />

A slightly more sophisticated method of populating the value for content would prefix this with basic item information.

Person - schema.org
http://schema.org/Person
<meta name="description" content="The schema.org type Person. A person (alive, dead, undead, or fictional)." />

inSupportOf - bib.schema.org
https://bib.schema.org/inSupportOf
<meta name="description" content="The bib.schema.org property inSupportOf. Qualification, candidature, degree, application that Thesis supports." />

InStock - schema.org
https://schema.org/InStock
<meta name="description" content="The schema.org enumeration inStock. Indicates that the item is in stock." />