Add first-class ChatGPT subscription provider support (#881)

* Add first-class ChatGPT subscription provider support

* Address PR feedback: move uuid import to top, reuse parsed config in up()

* Add ChatGPT token watchdog for seamless long-lived sessions

* Address PR feedback: error on stream=false for ChatGPT, fix auth file permissions

* Replace ChatGPT watchdog/restart with passthrough_auth

---------

Co-authored-by: Musa Malik <musam@uw.edu>

crates/hermesllm/src/bin/provider_models.yaml

@@ -329,6 +329,10 @@ providers:
   - xiaomi/mimo-v2-flash
   - xiaomi/mimo-v2-omni
   - xiaomi/mimo-v2-pro
+  chatgpt:
+  - chatgpt/gpt-5.4
+  - chatgpt/gpt-5.3-codex
+  - chatgpt/gpt-5.2
   digitalocean:
   - digitalocean/openai-gpt-4.1
   - digitalocean/openai-gpt-4o
@@ -376,6 +380,6 @@ providers:
   - digitalocean/qwen3-embedding-0.6b
   - digitalocean/router:software-engineering
 metadata:
-  total_providers: 12
-  total_models: 361
-  last_updated: 2026-04-16T00:00:00.000000+00:00
+  total_providers: 13
+  total_models: 364
+  last_updated: 2026-04-20T00:00:00.000000+00:00

crates/hermesllm/src/clients/endpoints.rs

@@ -192,7 +192,9 @@ impl SupportedAPIsFromClient {
                 // For Responses API, check if provider supports it, otherwise translate to chat/completions
                 match provider_id {
                     // Providers that support /v1/responses natively
-                    ProviderId::OpenAI | ProviderId::XAI => route_by_provider("/responses"),
+                    ProviderId::OpenAI | ProviderId::XAI | ProviderId::ChatGPT => {
+                        route_by_provider("/responses")
+                    }
                     // All other providers: translate to /chat/completions
                     _ => route_by_provider("/chat/completions"),
                 }

crates/hermesllm/src/providers/id.rs

@@ -44,6 +44,7 @@ pub enum ProviderId {
     Zhipu,
     Qwen,
     AmazonBedrock,
+    ChatGPT,
     DigitalOcean,
 }
 
@@ -72,6 +73,7 @@ impl TryFrom<&str> for ProviderId {
             "qwen" => Ok(ProviderId::Qwen),
             "amazon_bedrock" => Ok(ProviderId::AmazonBedrock),
             "amazon" => Ok(ProviderId::AmazonBedrock), // alias
+            "chatgpt" => Ok(ProviderId::ChatGPT),
             "digitalocean" => Ok(ProviderId::DigitalOcean),
             "do" => Ok(ProviderId::DigitalOcean),    // alias
             "do_ai" => Ok(ProviderId::DigitalOcean), // alias
@@ -99,6 +101,7 @@ impl ProviderId {
             ProviderId::Moonshotai => "moonshotai",
             ProviderId::Zhipu => "z-ai",
             ProviderId::Qwen => "qwen",
+            ProviderId::ChatGPT => "chatgpt",
             ProviderId::DigitalOcean => "digitalocean",
             _ => return Vec::new(),
         };
@@ -154,6 +157,7 @@ impl ProviderId {
                 | ProviderId::Moonshotai
                 | ProviderId::Zhipu
                 | ProviderId::Qwen
+                | ProviderId::ChatGPT
                 | ProviderId::DigitalOcean,
                 SupportedAPIsFromClient::AnthropicMessagesAPI(_),
             ) => SupportedUpstreamAPIs::OpenAIChatCompletions(OpenAIApi::ChatCompletions),
@@ -174,13 +178,14 @@ impl ProviderId {
                 | ProviderId::Moonshotai
                 | ProviderId::Zhipu
                 | ProviderId::Qwen
+                | ProviderId::ChatGPT
                 | ProviderId::DigitalOcean,
                 SupportedAPIsFromClient::OpenAIChatCompletions(_),
             ) => SupportedUpstreamAPIs::OpenAIChatCompletions(OpenAIApi::ChatCompletions),
 
-            // OpenAI Responses API - OpenAI and xAI support this natively
+            // OpenAI Responses API - OpenAI, xAI, and ChatGPT support this natively
             (
-                ProviderId::OpenAI | ProviderId::XAI,
+                ProviderId::OpenAI | ProviderId::XAI | ProviderId::ChatGPT,
                 SupportedAPIsFromClient::OpenAIResponsesAPI(_),
             ) => SupportedUpstreamAPIs::OpenAIResponsesAPI(OpenAIApi::Responses),
 
@@ -241,6 +246,7 @@ impl Display for ProviderId {
             ProviderId::Zhipu => write!(f, "zhipu"),
             ProviderId::Qwen => write!(f, "qwen"),
             ProviderId::AmazonBedrock => write!(f, "amazon_bedrock"),
+            ProviderId::ChatGPT => write!(f, "chatgpt"),
             ProviderId::DigitalOcean => write!(f, "digitalocean"),
         }
     }

crates/hermesllm/src/providers/request.rs

@@ -77,7 +77,7 @@ impl ProviderRequestType {
         &mut self,
         provider_id: ProviderId,
         upstream_api: &SupportedUpstreamAPIs,
-    ) {
+    ) -> Result<(), ProviderRequestError> {
         if provider_id == ProviderId::XAI
             && matches!(
                 upstream_api,
@@ -89,6 +89,48 @@ impl ProviderRequestType {
                 req.web_search_options = None;
             }
         }
+
+        // ChatGPT requires instructions, store=false, and input as a list
+        if provider_id == ProviderId::ChatGPT {
+            if let Self::ResponsesAPIRequest(req) = self {
+                use crate::apis::openai_responses::{
+                    InputItem, InputMessage, InputParam, MessageContent, MessageRole,
+                };
+
+                const CHATGPT_BASE_INSTRUCTIONS: &str =
+                    "You are Codex, based on GPT-5. You are running as a coding agent in the Codex CLI on a user's computer.";
+                match &req.instructions {
+                    Some(existing) if existing.contains(CHATGPT_BASE_INSTRUCTIONS) => {}
+                    Some(existing) => {
+                        req.instructions =
+                            Some(format!("{}\n\n{}", CHATGPT_BASE_INSTRUCTIONS, existing));
+                    }
+                    None => {
+                        req.instructions = Some(CHATGPT_BASE_INSTRUCTIONS.to_string());
+                    }
+                }
+                req.store = Some(false);
+                if req.stream == Some(false) {
+                    return Err(ProviderRequestError {
+                        message: "Non-streaming requests are not supported for the ChatGPT Codex provider. Set stream=true or omit the stream field.".to_string(),
+                        source: None,
+                    });
+                }
+                req.stream = Some(true);
+
+                // ChatGPT backend requires input to be a list, not a plain string
+                if let InputParam::Text(text) = &req.input {
+                    req.input = InputParam::Items(vec![InputItem::Message(InputMessage {
+                        role: MessageRole::User,
+                        content: MessageContent::Text(text.clone()),
+                    })]);
+                }
+                if let InputParam::SingleItem(item) = &req.input {
+                    req.input = InputParam::Items(vec![item.clone()]);
+                }
+            }
+        }
+        Ok(())
     }
 }
 
@@ -824,10 +866,12 @@ mod tests {
             ..Default::default()
         });
 
-        request.normalize_for_upstream(
-            ProviderId::XAI,
-            &SupportedUpstreamAPIs::OpenAIChatCompletions(OpenAIApi::ChatCompletions),
-        );
+        request
+            .normalize_for_upstream(
+                ProviderId::XAI,
+                &SupportedUpstreamAPIs::OpenAIChatCompletions(OpenAIApi::ChatCompletions),
+            )
+            .unwrap();
 
         let ProviderRequestType::ChatCompletionsRequest(req) = request else {
             panic!("expected chat request");
@@ -852,10 +896,12 @@ mod tests {
             ..Default::default()
         });
 
-        request.normalize_for_upstream(
-            ProviderId::OpenAI,
-            &SupportedUpstreamAPIs::OpenAIChatCompletions(OpenAIApi::ChatCompletions),
-        );
+        request
+            .normalize_for_upstream(
+                ProviderId::OpenAI,
+                &SupportedUpstreamAPIs::OpenAIChatCompletions(OpenAIApi::ChatCompletions),
+            )
+            .unwrap();
 
         let ProviderRequestType::ChatCompletionsRequest(req) = request else {
             panic!("expected chat request");