Changelog

5.26.0

(feat): Add an encode_path_params config option (default false). When enabled, path parameter values are percent-encoded when substituted into the request path, so a value containing / or .. can no longer change which endpoint the request resolves to. The default false preserves the existing (unencoded) behavior; TypeScript, Go, Java, and C# already encode path params.

5.25.0

(feat): Add opt-in allow_user_agent_app_info config (camelCase alias allowUserAgentAppInfo). When enabled, the generated client accepts an optional app_info ({"name": ..., "version"?: ..., "comment"?: ...}) constructor argument whose product token is appended to the User-Agent header ({sdk}/{version} ... {product}/{product-version} ({comment})), following RFC 9110. Disabled by default, so existing generated output is unchanged. It composes with include_platform_headers, the user-agent template config, and the default {package}/{version} value, and survives the runtime_version path. Caller-supplied values are sanitized (name/version token-encoded, comment delimiters and control characters escaped), and it is still overridable by an explicit User-Agent header and suppressed by omit_fern_headers.

5.24.2

(fix): Fix two issues with the opt-in allow_user_agent_app_info client option:

• The app_info constructor parameter no longer leaks a bare positional None into generated usage snippets and docstrings, which produced invalid Python (a positional argument after keyword arguments). It remains an optional keyword argument defaulting to None.
• Non-ASCII characters in the app_info comment are now percent-encoded (UTF-8). Previously they were passed through into the User-Agent header, causing httpx to raise UnicodeEncodeError on every request.