Whether this metadata was parsed from an actual authorization-server
metadata document discovered via RFC 8414 / OpenID Connect Discovery
(true), as opposed to synthesized from default endpoints for the
2025-03-26 no-document endpoint fallback (false). The MCP authorization
spec ("Authorization Code Protection") requires clients to refuse when a
*discovered* document omits code_challenge_methods_supported; the
no-document fallback case is treated separately. Set by fromJson.
Whether this metadata was parsed from an actual authorization-server metadata document discovered via RFC 8414 / OpenID Connect Discovery (true), as opposed to synthesized from default endpoints for the 2025-03-26 no-document endpoint fallback (false). The MCP authorization spec ("Authorization Code Protection") requires clients to refuse when a *discovered* document omits code_challenge_methods_supported; the no-document fallback case is treated separately. Set by fromJson.