I'd say some of the worldview is shared but the architecture and ethos is very different. Some major differences:

- AT tries to solve aggregation of public data first. I.e. it has to be able to express modern social media. Bluesky is a proof that it would work in production. AFAIK, Solid doesn't try to solve aggregation, and is focused on private data first. (AT plans private data support but not now.)

- AT embraces "apps describe on their own formats" (Lexicons). Solid uses RDF which is a very different model. My impression is RDF may be more powerful but is a lot more abstract. Lexicon is more or less like *.d.ts for JSON.