Changelog

4.65.1

(fix): Fixed a performance issue in fern check where valid-markdown-links repeatedly reprocessed duplicate API descriptions and pathnames in API sections, significantly improving runtime on large docs sites.

4.64.1

(chore): Tag Sentry errors with fern_run_id and github_run_id for cross-run correlation. The CLI now generates a FERN_RUN_ID at startup if one is not already set in the environment (e.g. by the fern-api/actions/setup-cli GitHub Action), threading a single correlation ID through all CLI invocations in a workflow run.

4.65.0

(feat): Add --output flag to fern sdk preview that accepts filesystem paths and/or registry URLs. Omit to publish to the default preview registry and write to a temp directory. Use --output <path> for disk-only output, or --output <path> --output <url> to write to disk and publish to a custom registry.

4.64.0

(feat): Support default on discriminant properties in OpenAPI discriminated unions. When a variant’s discriminant property has a default value matching its const value, the default variant is threaded through the IR so generators can fall back to it when the discriminant field is omitted. The x-fern-default extension takes priority over default if both are set.

4.63.5

(fix): Fix union variant display names showing “object” instead of proper schema names in documentation.

4.63.4

(fix): Add no-conflicting-parameter-names OSS validation rule to fern check. Detects when header parameters and query/path parameters on the same endpoint normalize to the same camelCase name, which causes broken generated SDK code (Python SyntaxError from duplicate keyword arguments, TypeScript duplicate interface properties). The rule reports an error at validation time so the collision is caught before code generation.

4.63.3

(fix): Fix coerce-enums-to-literals: false not being respected for boolean single-value enums (type: boolean, enum: [true]). Previously, boolean enums were always coerced to literals regardless of the setting. Now getSingleBooleanEnumValue checks coerceEnumsToLiterals consistently with the string enum path.

4.63.2

(fix): Add log rotation for fern docs dev debug logs in ~/.fern/logs/. Old log files are automatically deleted when the directory exceeds 100 MB, keeping the most recent logs.

4.63.1

(fix): Fix Go dynamic snippets not being generated during docs publish. The Go package name comparison between snippet configuration and generator output was failing due to an https:// prefix mismatch, causing docs to fall back to raw net/http code instead of SDK-idiomatic snippets.

4.63.0

(feat): Speed up fern docs dev bundle refresh by renaming the old bundle and deleting it asynchronously instead of blocking on removal.

4.62.6

(fix): Clean up Fern Docs cache on fern docs dev startup and shutdown.

4.62.5

(fix): Fix replay init to create .gitattributes with linguist-generated markers and sync .fernignore entries with fern-replay.

4.62.4

(chore): Internal CLI improvements.

4.62.3

(fix): Make GitHub token optional for replay init. Public repos no longer require a token.

4.62.1

(chore): Remove deprecated private field from DocsInstance configuration.

4.62.2

(fix): Fix OpenAPI importer dropping request body examples when the request body has no schema defined. Previously, endpoints with a JSON content type but no schema were treated as having no request body at all, causing valid example JSON to be lost. The importer now preserves the request and its examples so they render in docs and code snippets.

4.62.0

(feat): Make the fern api enrich command public. This command merges an AI examples overrides file into an OpenAPI spec, integrating x-fern-examples into native OpenAPI example fields.

4.60.0

(feat): Add agents.page-description-source to docs.yml to control which frontmatter field is preferred for one-line page descriptions in llms.txt. Supports description and subtitle, and falls back to other supported frontmatter fields when the preferred field is not present.

4.61.0

(feat): Add --email flag to fern login for enterprise SSO support.

4.59.0

(feat): Add support for pulling generator Docker images from custom container registries during fern generate --local via a new image: { name, registry } field in generators.yml. Custom image generators are blocked for remote generation and skipped during auto-upgrade.

4.58.0

(feat): Support x-fern-default on x-fern-global-headers entries. When a global header includes x-fern-default, the value is carried through to the IR clientDefault field so generators can emit optional parameters with a default value (e.g. version: Optional[str] = '2024-02-08').

4.57.0

(feat): Add a missing-redirects docs validation rule to fern check that compares the current docs navigation against the previously published markdown slug table in FDR. The check warns when a published page is removed or moved without a redirect in docs.yml, helping prevent broken historical docs URLs. The rule also handles first-publish, unauthenticated, offline, and timeout scenarios gracefully based on the configured check severity.

4.56.0

(feat): Add an agents config block to docs.yml for agent-serving endpoints. agents.page-directive prepends custom instructions to each page served through agent endpoints.

4.55.0

(feat): Send X-Deployer-Author and X-Deployer-Author-Email headers on docs registration requests so CI-triggered deployments can be attributed to the user who initiated the deploy.

4.54.1

(fix): Skip the CLI upgrade suggestion when the current version is 0.0.0, which is the placeholder used for local development builds.

4.53.2

(chore): Improve error messages for cli docs publishing.

4.54.0

(feat): Add x-fern-default OpenAPI extension for path, header, and query parameters. When present on a parameter, the value is carried through the OpenAPI IR and Fern definition into the IR clientDefault field (a Literal). Generators can read this field to emit optional parameters that automatically send the default value when the caller omits them. Supports string and boolean literal values.

4.53.1

(fix): Fix auto-generated path parameter examples producing object values (e.g. { key: "value" }) for unknown-typed path parameters. generatePathParameterExamples now coerces non-primitive values to a string fallback derived from the parameter name, preventing [object Object] from appearing in generated wire test URLs.

4.53.0

(feat): Log which group is being used when fern generate falls back to the default-group configured in generators.yml, so it is clear which group is running even when --group is not explicitly passed.

4.52.2

(chore): Fall back to reading auth and auth-schemes from the spec’s overrides file when no auth is configured in generators.yml. This allows auth configuration to live exclusively in the overrides file alongside other OpenAPI overrides, without needing to duplicate it in generators.yml.

4.52.1

(fix): Fix OpenAPI importer not converting boolean enums with a single value (type: boolean, enum: [true] or enum: [false]) into literal types. Previously these were treated as plain boolean; now they correctly produce literal<true> or literal<false> in the IR, resulting in literal types in generated SDKs (e.g. true in TypeScript, typing.Literal[True] in Python).

4.52.0

(feat): Add integrations.context7 to docs.yml so Fern can upload and publish a customer-provided context7.json verification file for docs sites.

4.51.0

(feat): Make dashboard the default launch option for the “Edit this page” button. Previously the default was github, which required users to configure launch: dashboard explicitly.

4.50.5

(fix): Fix example validation rejecting valid null values in anyOf/oneOf schemas. The ExampleConverter now correctly preserves explicit null examples (e.g. anyOf: [{type: "string"}, {type: "null"}] with "query": null) instead of treating them as missing or undefined. This affected both union conversion (nullish coalescing dropped null) and object property validation (null was treated as omitted when the schema allowed it via anyOf/oneOf).

4.50.4

(fix): Cache loaded OpenAPI documents across OSS validation rules to avoid redundant parsing and overlay application. Previously each of the 4 validator rules independently called loadOpenAPI(), causing the overlay log message to appear multiple times. Documents are now pre-loaded once and shared. Also demotes the overlay temp-file log from info to debug.

4.50.3

(fix): Improve MDX validation error formatting in fern docs md check.

4.50.2

(fix): Don’t exclude streaming request body ref schemas during stream condition processing, as they may be referenced by other operations and need to remain in the generated output.

4.50.1

(fix): Fix OpenAPI importer dropping object properties with type: "null" (valid in OpenAPI 3.1). Properties declared as type: "null" were silently filtered out before conversion, causing fields like conversation_id to disappear from generated SDK response models. The importer now represents type: "null" as nullable(unknown), producing unknown | null in TypeScript and Optional[Any] in Python.

4.50.0

(feat): Auto-infer x-fern-discriminator-context for discriminated unions that match the SSE event spec shape. When all variants of a discriminated union have properties exclusively drawn from {event, data, id, retry} with correct types, the discriminator context is now inferred as protocol instead of defaulting to data. This applies to the legacy OpenAPI importer.

4.49.0

(feat): Add body-sort option to webhook signature payload format. When set to alphabetical, POST body parameters are sorted by key before being concatenated into the signing payload. This is required by providers like Twilio. Supported in both Fern Definition (body-sort: alphabetical inside payload-format) and OpenAPI specs (body-sort: alphabetical inside the payload-format block of x-fern-webhook-signature).