July 14, 2026

2.76.0

(fix): Add an opt-in dedupe-union-base-properties configuration flag (default off) that stops duplicating a discriminated union’s base properties on its samePropertiesAsObject variant leaves. The decision is read from the IR fact ObjectTypeDeclaration.deferredUnionBaseProperties (computed once in the IR with structural type equality and an exclusive-variant guard), so the generator never re-derives it. When enabled, the union envelope owns the shared base properties, the variant leaf class and its example initializers omit them, and the union’s JSON reader strips union-owned properties before deserializing a variant. Off by default, so existing generated output is unchanged; the default is expected to flip in a future major version with a migration.

2.75.0

(feat): Add support for auto-generating an Idempotency-Key header on generated SDK clients, driven by the IR. When sdkConfig.idempotencyKeyGeneration is present (configured once via the auto-generate-idempotency-key generator config key and resolved by the CLI), the SDK attaches an idempotency-key request header whose value is a freshly generated UUIDv4 (System.Guid.NewGuid().ToString()) at request time. The wire header name and the eligible HTTP methods come from the IR, so behavior is consistent across every generator. A caller-provided value always wins: a declared idempotency header or a header supplied through request-options takes precedence, and the generated UUID is only a fallback. The header is only injected on the eligible methods. Disabled by default, so existing generated output is unchanged.

2.74.0

(feat): Add support for server URL variables (region/edge routing). When an API’s servers declare URL variables (e.g. https://api.{region}.example.com), each variable is now exposed as an optional string property on ClientOptions (idiomatic PascalCase, e.g. Region). Variable names that collide with an existing client option are prefixed with ServerUrl (e.g. an environment variable becomes ServerUrlEnvironment). When set at construction time, the values are interpolated into the environment base URL(s), falling back to each variable’s default otherwise. Explicit BaseUrl or Environment options take precedence, and interpolation fails clearly when a required variable has neither a client option nor a default.

2.73.2

(fix): Enable automatic response decompression on the default HttpClient. The default client is now created with an HttpClientHandler configured with AutomaticDecompression (DecompressionMethods.All on .NET 5+, GZip | Deflate on older targets), so responses with a Content-Encoding of gzip or deflate are decompressed transparently — including when an Accept-Encoding request header is set explicitly by the API spec. User-supplied HttpClients provided via ClientOptions are not modified.