> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getbifrost.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# v1.4.0-prerelease1

> v1.4.0-prerelease1 changelog - 2025-12-29

<Tabs>
  <Tab title="NPX">
    ```bash theme={null}
    npx -y @maximhq/bifrost --transport-version v1.4.0-prerelease1
    ```
  </Tab>

  <Tab title="Docker">
    ```bash theme={null}
    docker pull maximhq/bifrost:v1.4.0-prerelease1
    docker run -p 8080:8080 maximhq/bifrost:v1.4.0-prerelease1
    ```
  </Tab>
</Tabs>

<Update label="Bifrost(HTTP)" description="1.4.0-prerelease1">
  * refactor: governance plugin refactored for extensibility and optimization
  * feat: new MCP gateway (server including) along with code mode
  * feat: added health monitoring to mcp
  * feat: added responses format tool execution support to mcp
  * feat: new e2e tracing
  * fix: gemini thought signature handling in multi-turn conversations

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor removed, replaced with HTTPTransportMiddleware**

    The `TransportInterceptor` function has been removed from the plugin interface. Plugins using HTTP transport interception must migrate to `HTTPTransportMiddleware`.

    **Migration summary:**

    ```
    // v1.3.x (removed)
    TransportInterceptor(ctx *BifrostContext, url string, headers map[string]string, body map[string]any) (map[string]string, map[string]any, error)

    // v1.4.x+ (new)
    HTTPTransportMiddleware() BifrostHTTPMiddleware
    // where BifrostHTTPMiddleware = func(next fasthttp.RequestHandler) fasthttp.RequestHandler
    ```

    **Key API changes:**

    * Function renamed: `TransportInterceptor` -> `HTTPTransportMiddleware`
    * Signature changed: Now returns a middleware wrapper instead of accepting/returning header/body maps
    * Added dependency: Requires `github.com/valyala/fasthttp` import
    * Flow control: Must explicitly call `next(ctx)` to continue the chain

    See [Plugin Migration Guide](/plugins/migration-guide) for complete migration instructions and code examples.
</Update>

<Update label="Core" description="1.3.0">
  * feat: added code mode to mcp
  * feat: added health monitoring to mcp
  * feat: added responses format tool execution support to mcp
  * feat: adds central tracer for e2e tracing

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor removed, replaced with HTTPTransportMiddleware**

    The `TransportInterceptor` method has been removed from the `Plugin` interface in `schemas/plugin.go`. All plugins must now implement `HTTPTransportMiddleware()` instead.

    **Old API (removed in core v1.3.0):**

    ```go theme={null}
    TransportInterceptor(ctx *BifrostContext, url string, headers map[string]string, body map[string]any) (map[string]string, map[string]any, error)
    ```

    **New API (core v1.3.0+):**

    ```go theme={null}
    HTTPTransportMiddleware() BifrostHTTPMiddleware
    // where BifrostHTTPMiddleware = func(next fasthttp.RequestHandler) fasthttp.RequestHandler
    ```

    **Key changes:**

    * Method renamed: `TransportInterceptor` -> `HTTPTransportMiddleware`
    * Return type changed: Now returns a middleware function instead of modified headers/body
    * New import required: `github.com/valyala/fasthttp`
    * Flow control: Must call `next(ctx)` explicitly to continue the middleware chain
    * New capability: Can now intercept and modify responses (not just requests)

    **Migration for plugin consumers:**

    1. Update your plugin to implement `HTTPTransportMiddleware()` instead of `TransportInterceptor()`
    2. If your plugin doesn't need HTTP transport interception, return `nil` from `HTTPTransportMiddleware()`
    3. Update tests to verify the new middleware signature

    See [Plugin Migration Guide](/plugins/migration-guide) for complete instructions and code examples.
</Update>

<Update label="Framework" description="1.2.0">
  * feat: adds new tracing framework for allowing plugins to enable e2e tracing

  ### BREAKING CHANGES

  * **DynamicPlugin: TransportInterceptor replaced with HTTPTransportMiddleware**

    The `DynamicPlugin` loader now expects plugins to export `HTTPTransportMiddleware` instead of `TransportInterceptor`.

    **Old symbol lookup (removed in framework v1.2.0):**

    ```go theme={null}
    plugin.Lookup("TransportInterceptor")
    // Expected: func(ctx *BifrostContext, url string, headers map[string]string, body map[string]any) (map[string]string, map[string]any, error)
    ```

    **New symbol lookup (framework v1.2.0+):**

    ```go theme={null}
    plugin.Lookup("HTTPTransportMiddleware")
    // Expected: func() BifrostHTTPMiddleware
    ```

    **Impact on dynamic plugins (.so files):**

    * Plugins compiled for core v1.2.x will fail to load with error: `plugin: symbol HTTPTransportMiddleware not found`
    * Recompile all dynamic plugins against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for migration instructions.
</Update>

<Update label="governance" description="1.4.0">
  * refactor: extracted governance store into an interface for extensibility
  * refactor: extended the way governance store handles rate limits
  * chore: added e2e tests for governance plugin
  * chore: upgraded versions of core to 1.3.0 and framework to 1.2.0

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor replaced with HTTPTransportMiddleware**

    This plugin now implements `HTTPTransportMiddleware()` instead of `TransportInterceptor()` to comply with core v1.3.0.

    **What changed:**

    * Old: `TransportInterceptor(ctx, url, headers, body) (headers, body, error)`
    * New: `HTTPTransportMiddleware() BifrostHTTPMiddleware`

    **For plugin consumers:**

    * If you import this plugin directly, no code changes are required
    * If you extend this plugin, update your implementation to use `HTTPTransportMiddleware()`
    * Recompile any code that depends on this plugin against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for details.
</Update>

<Update label="jsonparser" description="1.4.0">
  * chore: upgraded versions of core to 1.3.0 and framework to 1.2.0

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor replaced with HTTPTransportMiddleware**

    This plugin now implements `HTTPTransportMiddleware()` instead of `TransportInterceptor()` to comply with core v1.3.0.

    **What changed:**

    * Old: `TransportInterceptor(ctx, url, headers, body) (headers, body, error)`
    * New: `HTTPTransportMiddleware() BifrostHTTPMiddleware`

    **For plugin consumers:**

    * If you import this plugin directly, no code changes are required
    * If you extend this plugin, update your implementation to use `HTTPTransportMiddleware()`
    * Recompile any code that depends on this plugin against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for details.
</Update>

<Update label="logging" description="1.4.0">
  * feat: logging now uses central accumulator vs its own; reducing total memory consumption during runtime
  * chore: upgraded versions of core to 1.3.0 and framework to 1.2.0

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor replaced with HTTPTransportMiddleware**

    This plugin now implements `HTTPTransportMiddleware()` instead of `TransportInterceptor()` to comply with core v1.3.0.

    **What changed:**

    * Old: `TransportInterceptor(ctx, url, headers, body) (headers, body, error)`
    * New: `HTTPTransportMiddleware() BifrostHTTPMiddleware`

    **For plugin consumers:**

    * If you import this plugin directly, no code changes are required
    * If you extend this plugin, update your implementation to use `HTTPTransportMiddleware()`
    * Recompile any code that depends on this plugin against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for details.
</Update>

<Update label="maxim" description="1.5.0">
  * chore: upgraded versions of core to 1.3.0 and framework to 1.2.0

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor replaced with HTTPTransportMiddleware**

    This plugin now implements `HTTPTransportMiddleware()` instead of `TransportInterceptor()` to comply with core v1.3.0.

    **What changed:**

    * Old: `TransportInterceptor(ctx, url, headers, body) (headers, body, error)`
    * New: `HTTPTransportMiddleware() BifrostHTTPMiddleware`

    **For plugin consumers:**

    * If you import this plugin directly, no code changes are required
    * If you extend this plugin, update your implementation to use `HTTPTransportMiddleware()`
    * Recompile any code that depends on this plugin against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for details.
</Update>

<Update label="mocker" description="1.4.0">
  * chore: upgraded versions of core to 1.3.0 and framework to 1.2.0

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor replaced with HTTPTransportMiddleware**

    This plugin now implements `HTTPTransportMiddleware()` instead of `TransportInterceptor()` to comply with core v1.3.0.

    **What changed:**

    * Old: `TransportInterceptor(ctx, url, headers, body) (headers, body, error)`
    * New: `HTTPTransportMiddleware() BifrostHTTPMiddleware`

    **For plugin consumers:**

    * If you import this plugin directly, no code changes are required
    * If you extend this plugin, update your implementation to use `HTTPTransportMiddleware()`
    * Recompile any code that depends on this plugin against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for details.
</Update>

<Update label="otel" description="1.1.0">
  * feat: otel now uses central accumulator reducing the total amount of memory consumed in runtime
  * chore: upgraded versions of core to 1.3.0 and framework to 1.2.0

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor replaced with HTTPTransportMiddleware**

    This plugin now implements `HTTPTransportMiddleware()` instead of `TransportInterceptor()` to comply with core v1.3.0.

    **What changed:**

    * Old: `TransportInterceptor(ctx, url, headers, body) (headers, body, error)`
    * New: `HTTPTransportMiddleware() BifrostHTTPMiddleware`

    **For plugin consumers:**

    * If you import this plugin directly, no code changes are required
    * If you extend this plugin, update your implementation to use `HTTPTransportMiddleware()`
    * Recompile any code that depends on this plugin against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for details.
</Update>

<Update label="semantic_cache" description="1.4.0">
  * chore: upgraded versions of core to 1.3.0 and framework to 1.2.0

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor replaced with HTTPTransportMiddleware**

    This plugin now implements `HTTPTransportMiddleware()` instead of `TransportInterceptor()` to comply with core v1.3.0.

    **What changed:**

    * Old: `TransportInterceptor(ctx, url, headers, body) (headers, body, error)`
    * New: `HTTPTransportMiddleware() BifrostHTTPMiddleware`

    **For plugin consumers:**

    * If you import this plugin directly, no code changes are required
    * If you extend this plugin, update your implementation to use `HTTPTransportMiddleware()`
    * Recompile any code that depends on this plugin against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for details.
</Update>

<Update label="telemetry" description="1.4.0">
  * chore: upgraded versions of core to 1.3.0 and framework to 1.2.0

  ### BREAKING CHANGES

  * **Plugin Interface: TransportInterceptor replaced with HTTPTransportMiddleware**

    This plugin now implements `HTTPTransportMiddleware()` instead of `TransportInterceptor()` to comply with core v1.3.0.

    **What changed:**

    * Old: `TransportInterceptor(ctx, url, headers, body) (headers, body, error)`
    * New: `HTTPTransportMiddleware() BifrostHTTPMiddleware`

    **For plugin consumers:**

    * If you import this plugin directly, no code changes are required
    * If you extend this plugin, update your implementation to use `HTTPTransportMiddleware()`
    * Recompile any code that depends on this plugin against core v1.3.0+ and framework v1.2.0+

    See [Plugin Migration Guide](/plugins/migration-guide) for details.
</Update>