Changelog

3.88.2

(fix): Fix fern check validation for SSE streaming endpoints with protocol-level discrimination. Examples for SSE endpoints using context: protocol discriminated unions were rejected with “Missing discriminant property” because the validator looked for the discriminant inside the data payload instead of recognizing it at the SSE envelope level (event: field).

3.88.0

(feat): Add Replay support for preserving SDK customizations across regenerations. Replay detects user edits via .fern/replay.lock, applies them with 3-way merge, and creates PRs with conflict resolution guidance when needed.

New CLI commands: fern replay init, fern replay status, fern replay forget, fern replay reset. New --no-replay flag on fern generate to skip patch application. Gated behind replay: { enabled: true } in generators.yml.

3.87.0

(feat): Added collapsible and collapsed-by-default options for docs.yml navigation sections/folders, preserving the legacy collapsed behavior while adding validation to prevent invalid configurations.

3.86.1

(fix): Fall back to initial version 0.0.1 when AUTO versioning cannot extract the previous version instead of failing the entire generation. This handles new SDK repositories where all files are additions and no previous version lines exist in the diff.

3.86.0

(feat): Add support for x-fern-sdk-method-name extension on AsyncAPI WebSocket channels to customize the connection method name in generated SDKs. This field is now available in both AsyncAPI v2 and v3 specifications.

AsyncAPI example — use x-fern-sdk-method-name to customize the WebSocket connection method instead of the default “connect”:

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asyncapi: 3.0.0
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info:
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  title: Chat API
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  version: 1.0.0
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channels:
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  /chat:
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    x-fern-sdk-method-name: createChatConnection
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    messages:
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      userMessage:
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        payload:
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          type: object
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          properties:
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            content:
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              type: string

This generates client.createChatConnection() instead of client.connect(), avoiding confusing APIs where both wrapper creation and actual connection use “connect”.

3.85.6

(chore): Complete document-level webhook-signature configuration parsing. Adds validation for webhook signature configs (algorithms, encodings, timestamp settings, JWKS consistency).

3.85.5

(fix): Report broken AsyncAPI V3 message references as visible warnings instead of silently dropping entire specs. When an operation references a non-existent channel or message (e.g. $ref: "#/channels/auth/messages/authenticate" when no auth channel exists), the parser now logs a warning with the specific broken $ref and continues processing the remaining valid messages and channels.

3.85.4

(fix): Skip compatible IR version validation when running in local development mode (CLI version 0.0.0). This prevents noisy 404 errors from the FDR registry when the CLI version is not a real published release.

3.85.3

(fix): Remove unhelpful “Unable to analyze changes with AI” fallback message from changelog entries when AI analysis fails during AUTO versioning. The changelog now shows just the version header with no body instead.

3.85.1

(fix): Fix AUTO versioning failing for new SDK repositories. When generating an SDK into an empty or newly initialized repository, the version extraction would fail because all files are new additions with no previous version lines in the diff. Now returns 0.0.1 as the initial version instead of throwing an error.