# December 5, 2025

## 3.4.1

**`(fix):`** Map error response headers from IR to FDR for docs display.

## 3.4.0

**`(chore):`** Upgrade `@fern-api/fdr-sdk` to version `0.142.1-b1f6b6363` which adds support for error response headers.

## 3.3.0

**`(feat):`** Extend `substitute-env-vars` to apply to API specs (OpenAPI and Fern definitions) when generating docs. Environment variables using `${VAR_NAME}` syntax in API spec descriptions, examples, and other string fields are now substituted when `substitute-env-vars: true` is set in `docs.yml`.

## 3.2.0

**`(feat):`** Add recursive markdown snippet resolution for docs. Markdown snippets can now reference other markdown snippets, with automatic detection and warning for circular references to prevent infinite loops.

## 3.1.0

**`(feat):`** Preserve error response headers (e.g., Retry-After for 429 errors) from OpenAPI specs in the IR.

## 3.0.5

**`(fix):`** Fix AsyncAPI validation: exclude AsyncAPI files from OpenAPI-specific validation rules

## 3.0.4

**`(fix):`** Fix error response examples not displaying in docs when examples are defined at the property level in OpenAPI specs.