A capability token is a credential that is the authority — holding it lets you do exactly what it encodes, nothing more.
In a capability model, access isn't decided by looking you up in an access-control list; it's decided by what token you present. The token names the resource and the allowed operations. This makes delegation natural (hand over a token), least privilege easy (mint a narrow token), and verification local (check the token's signature — no central lookup).
Classic capabilities (object-capability systems, macaroons, biscuits) inspired Liceat's warrants. A warrant is a public-key capability token with attenuation (it can only be narrowed), stateful caveats (spend and rate limits), holder-binding, and revocation — the properties an autonomous agent needs.
A JWT is typically an identity/claims token verified by a server that then applies its own policy. A capability token embeds the policy: it says what may be done, is attenuable by the holder without calling the issuer, and (for warrants) supports offline sub-delegation that can only narrow.
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