feat: OpenAI LLMProvider adapter

Cargo.toml

@@ -92,6 +92,7 @@ unused_qualifications = "warn"
 [features]
 default = []
 bedrock = ["polaris_internal/bedrock"]
+openai = ["polaris_internal/openai"]
 
 [dependencies]
 polaris_internal = { path = "crates/polaris_internal", version = "0.0.1" }

crates/polaris_internal/Cargo.toml

@@ -7,6 +7,7 @@ keywords = []
 
 [features]
 default = []
+openai = ["polaris_model_providers/openai"]
 bedrock = ["polaris_model_providers/bedrock"]
 
 [dependencies]

crates/polaris_model_providers/Cargo.toml

@@ -10,6 +10,7 @@ workspace = true
 [features]
 default = ["anthropic"]
 anthropic = []
+openai = ["dep:async-openai"]
 bedrock = [
     "dep:aws-sdk-bedrockruntime",
     "dep:aws-config",
@@ -27,6 +28,13 @@ serde_json = "1.0"
 reqwest = { version = "0.13.1", features = ["json"] }
 tracing = "0.1"
 
+# OpenAI dependencies
+async-openai = { version = "0.33", optional = true, default-features = false, features = [
+    "rustls",
+    "responses",
+    "response-types",
+] }
+
 # AWS Bedrock dependencies
 aws-sdk-bedrockruntime = { version = "1.124.0", optional = true }
 aws-config = { version = "1.5", features = [

crates/polaris_model_providers/src/lib.rs

@@ -7,6 +7,7 @@
 //! | Provider | Feature Flag | Description |
 //! |----------|--------------|-------------|
 //! | Anthropic | `anthropic` (default) | Direct Anthropic API access |
+//! | `OpenAI` | `openai` | `OpenAI` Responses API |
 //! | AWS Bedrock | `bedrock` | AWS Bedrock Converse API |
 //!
 //! # Feature Flags
@@ -20,8 +21,11 @@
 //! # Enable only Bedrock
 //! polaris_model_providers = { path = "../polaris_model_providers", default-features = false, features = ["bedrock"] }
 //!
-//! # Enable both providers
-//! polaris_model_providers = { path = "../polaris_model_providers", features = ["bedrock"] }
+//! # Enable OpenAI
+//! polaris_model_providers = { path = "../polaris_model_providers", default-features = false, features = ["openai"] }
+//!
+//! # Enable multiple providers
+//! polaris_model_providers = { path = "../polaris_model_providers", features = ["openai", "bedrock"] }
 //! ```
 //!
 //! # Usage
@@ -49,6 +53,18 @@
 //! server.add_plugins(ModelsPlugin);
 //! server.add_plugins(BedrockPlugin::from_env());
 //! ```
+//!
+//! For `OpenAI`, provide an API key via environment variable:
+//!
+//! ```ignore
+//! use polaris_model_providers::OpenAiPlugin;
+//! use polaris_models::ModelsPlugin;
+//! use polaris_system::server::Server;
+//!
+//! let mut server = Server::new();
+//! server.add_plugins(ModelsPlugin);
+//! server.add_plugins(OpenAiPlugin::from_env("OPENAI_API_KEY"));
+//! ```
 
 mod schema;
 
@@ -58,6 +74,12 @@ pub mod anthropic;
 #[cfg(feature = "anthropic")]
 pub use anthropic::AnthropicPlugin;
 
+#[cfg(feature = "openai")]
+pub mod openai;
+
+#[cfg(feature = "openai")]
+pub use openai::OpenAiPlugin;
+
 #[cfg(feature = "bedrock")]
 pub mod bedrock;
 

crates/polaris_model_providers/src/openai/mod.rs

@@ -0,0 +1,9 @@
+//! `OpenAI` provider backend.
+//!
+//! Uses the `OpenAI` Responses API.
+
+mod plugin;
+mod provider;
+
+pub use plugin::OpenAiPlugin;
+pub use provider::OpenAiProvider;

crates/polaris_model_providers/src/openai/plugin.rs

@@ -0,0 +1,50 @@
+//! `OpenAI` provider plugin.
+
+use super::provider::OpenAiProvider;
+use polaris_models::{ModelRegistry, ModelsPlugin};
+use polaris_system::plugin::{Plugin, PluginId, Version};
+use polaris_system::server::Server;
+use std::sync::Arc;
+
+/// Plugin providing support for `OpenAI` models via the Responses API.
+///
+/// ```ignore
+/// server.add_plugins(OpenAiPlugin::from_env("OPENAI_API_KEY"));
+/// ```
+pub struct OpenAiPlugin {
+    api_key: String,
+}
+
+impl OpenAiPlugin {
+    /// Creates a plugin that reads the API key from the specified environment variable.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the environment variable is not set.
+    #[must_use]
+    pub fn from_env(env_var: &str) -> Self {
+        let api_key = std::env::var(env_var).unwrap_or_else(|_| {
+            panic!("Environment variable {env_var} for OpenAiPlugin not set. Please set it to your OpenAI API key.");
+        });
+        Self { api_key }
+    }
+}
+
+impl Plugin for OpenAiPlugin {
+    const ID: &'static str = "polaris::provider::openai";
+    const VERSION: Version = Version::new(0, 0, 1);
+
+    fn dependencies(&self) -> Vec<PluginId> {
+        vec![PluginId::of::<ModelsPlugin>()]
+    }
+
+    fn build(&self, server: &mut Server) {
+        let provider = OpenAiProvider::new(self.api_key.clone());
+
+        let Some(mut registry) = server.get_resource_mut::<ModelRegistry>() else {
+            panic!("ModelRegistry not found. Make sure to add ModelsPlugin before OpenAiPlugin.");
+        };
+
+        registry.register_llm_provider("openai", Arc::new(provider));
+    }
+}