docs: document allowUserAgentAppInfo for Go, C#, Java, Ruby, and PHP SDKs

fern/products/sdks/generators/csharp/configuration.mdx

@@ -99,6 +99,25 @@ When enabled, the generated SDK omits the `X-Fern-Language`, `X-Fern-SDK-Name`,
 When enabled, the generated SDK sends a single structured `User-Agent` header of the form `{sdkName}/{version} ({os}; {arch}) {runtime}/{runtimeVersion}` (for example, `my-sdk/1.2.0 (linux; x86_64) dotnet/8.0.4`), carrying SDK, operating system, architecture, and runtime information in place of the default `User-Agent` and discrete platform headers. If `omit-fern-headers` is enabled, no `User-Agent` or platform headers are sent and this option has no effect.
 </ParamField>
 
+<ParamField path="allow-user-agent-app-info" type="boolean" default="false" required={false} toc={true}>
+When enabled, the generated SDK emits an `AppInfo` record with a required `Name` and optional `Version` and `Comment`, and exposes it as an `AppInfo` property on `ClientOptions`. Its product token is appended to the `User-Agent` header, which lets an application built on the SDK identify itself to the API, following the [HTTP `User-Agent` grammar](https://www.rfc-editor.org/rfc/rfc9110#name-user-agent).
+
+```csharp
+var client = new AcmeApiClient("...", new ClientOptions
+{
+    AppInfo = new AppInfo { Name = "partner-app", Version = "3.1.0", Comment = "+https://partner.example" }
+});
+```
+
+The token is formatted as `{Name}/{Version} ({Comment})`, dropping `/{Version}` and `({Comment})` when blank, and is appended to whatever `User-Agent` the SDK would otherwise send, including the structured header from [`include-platform-headers`](#include-platform-headers):
+
+```
+User-Agent: my-sdk/1.2.0 (linux; x86_64) dotnet/8.0.4 partner-app/3.1.0 (+https://partner.example)
+```
+
+Caller-supplied values are sanitized before they reach the header. An explicit `User-Agent` header takes precedence, the header is unchanged when no `AppInfo` is set, and [`omit-fern-headers`](#omit-fern-headers) suppresses it entirely.
+</ParamField>
+
 <ParamField path="package-id" type="string" required={false} toc={true}>
 Sets the NuGet package identifier for the generated SDK. This is used when publishing the SDK to NuGet or other package repositories.
 </ParamField>

fern/products/sdks/generators/go/configuration.mdx

@@ -58,6 +58,25 @@ When enabled, the generated SDK omits the `X-Fern-Language`, `X-Fern-SDK-Name`,
 When enabled, the generated SDK sends a single structured `User-Agent` header of the form `{sdkName}/{version} ({os}; {arch}) {runtime}/{runtimeVersion}` (for example, `my-sdk/0.0.1 (linux; x86_64) Go/1.22.0`), carrying SDK, operating system, architecture, and runtime information in place of the default `User-Agent` and discrete platform headers. If `omitFernHeaders` is enabled, no `User-Agent` or platform headers are sent and this option has no effect.
 </ParamField>
 
+<ParamField path="allowUserAgentAppInfo" type="boolean" default="false" required={false} toc={true}>
+When enabled, the generated SDK exposes an `option.WithUserAgentAppInfo(name, version, comment)` option, with a required name and optional version and comment (pass `""` to omit either). Its product token is appended to the `User-Agent` header, which lets an application built on the SDK identify itself to the API, following the [HTTP `User-Agent` grammar](https://www.rfc-editor.org/rfc/rfc9110#name-user-agent).
+
+```go
+client := acmeclient.NewClient(
+    option.WithToken("..."),
+    option.WithUserAgentAppInfo("partner-app", "3.1.0", "+https://partner.example"),
+)
+```
+
+The token is formatted as `{name}/{version} ({comment})`, dropping `/{version}` and `({comment})` when blank, and is appended to whatever `User-Agent` the SDK would otherwise send, including the structured header from [`includePlatformHeaders`](#includeplatformheaders):
+
+```
+User-Agent: my-sdk/0.0.1 (linux; x86_64) Go/1.22.0 partner-app/3.1.0 (+https://partner.example)
+```
+
+Caller-supplied values are sanitized before they reach the header. An explicit `User-Agent` header takes precedence, the header is unchanged when no name is passed, and [`omitFernHeaders`](#omitfernheaders) suppresses it entirely.
+</ParamField>
+
 <ParamField path="enableWireTests" type="boolean" default="true" required={false} toc={true}>
 Generates [mock server (wire) tests](/sdks/deep-dives/testing#mock-server-tests) to verify that the SDK sends the correct HTTP requests and correctly handles responses per the API spec. When enabled, Docker is required as a runtime dependency to run the generated tests.
 </ParamField>

fern/products/sdks/generators/java/configuration.mdx

@@ -117,6 +117,25 @@ When enabled, the generated SDK omits the `X-Fern-Language`, `X-Fern-SDK-Name`,
 When enabled, the generated SDK sends a single structured `User-Agent` header of the form `{sdkName}/{version} ({os}; {arch}) {runtime}/{runtimeVersion}` (for example, `com.fern.sdk/0.0.1 (linux; x86_64) Java/17.0.13`), carrying SDK, operating system, architecture, and runtime information in place of the default `User-Agent` and discrete platform headers. If `omit-fern-headers` is enabled, no `User-Agent` or platform headers are sent and this option has no effect.
 </ParamField>
 
+<ParamField path="allowUserAgentAppInfo" type="boolean" default="false" required={false} toc={true}>
+When enabled, the generated client builder exposes an `appInfo(String name, String version, String comment)` method, with a required name and optional version and comment (pass `null` to omit either). Its product token is appended to the `User-Agent` header, which lets an application built on the SDK identify itself to the API, following the [HTTP `User-Agent` grammar](https://www.rfc-editor.org/rfc/rfc9110#name-user-agent).
+
+```java
+AcmeApiClient client = AcmeApiClient.builder()
+    .token("...")
+    .appInfo("partner-app", "3.1.0", "+https://partner.example")
+    .build();
+```
+
+The token is formatted as `{name}/{version} ({comment})`, dropping `/{version}` and `({comment})` when blank, and is appended to whatever `User-Agent` the SDK would otherwise send, including the structured header from [`includePlatformHeaders`](#includeplatformheaders) and the version resolved by [`runtime-version`](#runtime-version):
+
+```
+User-Agent: com.fern.sdk/0.0.1 (linux; x86_64) Java/17.0.13 partner-app/3.1.0 (+https://partner.example)
+```
+
+Caller-supplied values are sanitized before they reach the header. An explicit `User-Agent` header takes precedence, the header is unchanged when no name is passed, and [`omit-fern-headers`](#omit-fern-headers) suppresses it entirely.
+</ParamField>
+
 <ParamField path="package-layout" type="'nested' | 'flat'" default="nested" required={false} toc={true}>
 Determines the organization of generated Java packages. Choose 'nested' for a hierarchical package structure that mirrors your API organization, or 'flat' for a simpler structure with fewer nested packages.
 </ParamField>

fern/products/sdks/generators/php/configuration.mdx

@@ -61,6 +61,24 @@ When enabled, the generated SDK omits the `X-Fern-Language`, `X-Fern-SDK-Name`,
 When enabled, the generated SDK sends a single structured `User-Agent` header of the form `{sdkName}/{version} ({os}; {arch}) {runtime}/{runtimeVersion}` (for example, `my-sdk/0.0.1 (linux; x86_64) PHP/8.2.0`), carrying SDK, operating system, architecture, and runtime information in place of the default `User-Agent` and discrete platform headers. If `omitFernHeaders` is enabled, no `User-Agent` or platform headers are sent and this option has no effect.
 </ParamField>
 
+<ParamField path="allowUserAgentAppInfo" type="boolean" default="false" required={false} toc={true}>
+When enabled, the generated client accepts an optional `appInfo` client option of the shape `array{name: string, version?: string, comment?: string}`. Its product token is appended to the `User-Agent` header, which lets an application built on the SDK identify itself to the API, following the [HTTP `User-Agent` grammar](https://www.rfc-editor.org/rfc/rfc9110#name-user-agent).
+
+```php
+$client = new AcmeClient('...', [
+    'appInfo' => ['name' => 'partner-app', 'version' => '3.1.0', 'comment' => '+https://partner.example'],
+]);
+```
+
+The token is formatted as `{name}/{version} ({comment})`, dropping `/{version}` and `({comment})` when blank, and is appended to whatever `User-Agent` the SDK would otherwise send, including the structured header from [`includePlatformHeaders`](#includeplatformheaders):
+
+```
+User-Agent: my-sdk/0.0.1 (linux; x86_64) PHP/8.2.0 partner-app/3.1.0 (+https://partner.example)
+```
+
+Caller-supplied values are sanitized before they reach the header. An explicit `User-Agent` header takes precedence, the header is unchanged when no `appInfo` is passed, and [`omitFernHeaders`](#omitfernheaders) suppresses it entirely.
+</ParamField>
+
 <ParamField path="packageName" type="string" required={false} toc={true}>
 Sets the name of the PHP package as it will appear in Composer and Packagist. This is the name users will use to install the SDK via Composer (e.g., `composer require your/package-name`).
 </ParamField>

fern/products/sdks/generators/ruby/configuration.mdx

@@ -104,6 +104,25 @@ When enabled, the generated SDK omits the `X-Fern-Language`, `X-Fern-SDK-Name`,
 When enabled, the generated SDK sends a single structured `User-Agent` header of the form `{sdkName}/{version} ({os}; {arch}) {runtime}/{runtimeVersion}` (for example, `my-sdk/0.0.1 (linux; x86_64) Ruby/3.2.0`), carrying SDK, operating system, architecture, and runtime information in place of the default `User-Agent` and discrete platform headers. If `omitFernHeaders` is enabled, no `User-Agent` or platform headers are sent and this option has no effect.
 </ParamField>
 
+<ParamField path="allowUserAgentAppInfo" type="boolean" default="false" required={false} toc={true}>
+When enabled, the generated client accepts an optional `app_info` keyword of the shape `{ name:, version:, comment: }`, where `name` is required. Its product token is appended to the `User-Agent` header, which lets an application built on the SDK identify itself to the API, following the [HTTP `User-Agent` grammar](https://www.rfc-editor.org/rfc/rfc9110#name-user-agent).
+
+```ruby
+client = Acme::Client.new(
+  token: "...",
+  app_info: { name: "partner-app", version: "3.1.0", comment: "+https://partner.example" }
+)
+```
+
+The token is formatted as `{name}/{version} ({comment})`, dropping `/{version}` and `({comment})` when blank, and is appended to whatever `User-Agent` the SDK would otherwise send, including the structured header from [`includePlatformHeaders`](#includeplatformheaders):
+
+```
+User-Agent: my-sdk/0.0.1 (linux; x86_64) Ruby/3.2.0 partner-app/3.1.0 (+https://partner.example)
+```
+
+Caller-supplied values are sanitized before they reach the header. An explicit `User-Agent` header takes precedence, the header is unchanged when no `app_info` is passed, and [`omitFernHeaders`](#omitfernheaders) suppresses it entirely.
+</ParamField>
+
 <ParamField path="requirePaths" type="array of strings" required={false} toc={true}>
 <Markdown src="/snippets/enterprise-plan.mdx"/>