feat: integrate custom-openai provider namespace with separate env vars

- Add 'custom-openai' provider kind to setup_wizard.rs with distinct env namespace
- Add CustomOpenAi variant to ProviderConfigKind enum in api/client.rs
- Implement OpenAiCompatConfig::custom_openai() for custom-openai endpoint
- Update explicit_provider_kind_for_model() to handle 'custom-openai/' prefix
- Add tests for custom-openai configuration persistence across runtime boundary

Co-authored-by: TheArchitectit <thearchitectit@users.noreply.github.com>

Fixes #3248

rust/crates/api/src/client.rs

@@ -15,13 +15,15 @@ pub enum ProviderClient {
 
 /// Provider selected explicitly by persisted/runtime configuration.
 ///
-/// This is intentionally separate from `ProviderKind`: DashScope speaks the
-/// OpenAI-compatible wire protocol but remains a distinct configured provider.
+/// This is intentionally separate from `ProviderKind`: Custom OpenAI and
+/// DashScope speak the OpenAI-compatible wire protocol but remain distinct
+/// configured providers.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum ProviderConfigKind {
     Anthropic,
     Xai,
     OpenAi,
+    CustomOpenAi,
     DashScope,
 }
 
@@ -96,9 +98,12 @@ impl ProviderClient {
 
                 Ok(Self::Xai(client))
             }
-            ProviderConfigKind::OpenAi | ProviderConfigKind::DashScope => {
+            ProviderConfigKind::OpenAi
+            | ProviderConfigKind::CustomOpenAi
+            | ProviderConfigKind::DashScope => {
                 let compat = match config.kind {
                     ProviderConfigKind::OpenAi => OpenAiCompatConfig::openai(),
+                    ProviderConfigKind::CustomOpenAi => OpenAiCompatConfig::custom_openai(),
                     ProviderConfigKind::DashScope => OpenAiCompatConfig::dashscope(),
                     _ => unreachable!("non-OpenAI provider reached compatibility path"),
                 };
@@ -403,6 +408,56 @@ mod tests {
         }
     }
 
+    #[test]
+    fn persisted_custom_openai_uses_its_own_environment_namespace() {
+        let _lock = env_lock();
+        let _custom_key = EnvVarGuard::set("CLAWCUSTOMOPENAI_API_KEY", Some("custom-key"));
+        let _custom_url = EnvVarGuard::set(
+            "CLAWCUSTOMOPENAI_BASE_URL",
+            Some("https://custom.example/v1"),
+        );
+        let _openai_key = EnvVarGuard::set("OPENAI_API_KEY", Some("openai-key"));
+        let _openai_url = EnvVarGuard::set("OPENAI_BASE_URL", Some("https://openai.example/v1"));
+        let _ollama = EnvVarGuard::set("OLLAMA_HOST", Some("http://localhost:11434"));
+
+        let config = ProviderConfig {
+            kind: ProviderConfigKind::CustomOpenAi,
+            model: "qwen-plus".to_string(),
+            api_key: None,
+            base_url: None,
+        };
+
+        match ProviderClient::from_config(&config).expect("custom OpenAI config should succeed") {
+            ProviderClient::OpenAi(client) => {
+                assert_eq!(client.base_url(), "https://custom.example/v1");
+            }
+            other => panic!("Expected custom OpenAI provider, got: {other:?}"),
+        }
+    }
+
+    #[test]
+    fn persisted_custom_openai_does_not_reuse_openai_credentials() {
+        let _lock = env_lock();
+        let _custom_key = EnvVarGuard::set("CLAWCUSTOMOPENAI_API_KEY", None);
+        let _custom_url = EnvVarGuard::set(
+            "CLAWCUSTOMOPENAI_BASE_URL",
+            Some("https://custom.example/v1"),
+        );
+        let _openai_key = EnvVarGuard::set("OPENAI_API_KEY", Some("openai-key"));
+        let _ollama = EnvVarGuard::set("OLLAMA_HOST", Some("http://localhost:11434"));
+
+        let config = ProviderConfig {
+            kind: ProviderConfigKind::CustomOpenAi,
+            model: "gpt-5".to_string(),
+            api_key: None,
+            base_url: None,
+        };
+
+        let error = ProviderClient::from_config(&config)
+            .expect_err("custom OpenAI must require its own credentials");
+        assert!(error.to_string().contains("CLAWCUSTOMOPENAI_API_KEY"));
+    }
+
     #[test]
     fn dashscope_model_uses_dashscope_config_not_openai() {
         // Regression: qwen-plus was being routed to OpenAiCompatConfig::openai()

rust/crates/api/src/providers/openai_compat.rs

@@ -42,6 +42,7 @@ pub struct OpenAiCompatConfig {
 
 const XAI_ENV_VARS: &[&str] = &["XAI_API_KEY"];
 const OPENAI_ENV_VARS: &[&str] = &["OPENAI_API_KEY"];
+const CUSTOM_OPENAI_ENV_VARS: &[&str] = &["CLAWCUSTOMOPENAI_API_KEY"];
 const DASHSCOPE_ENV_VARS: &[&str] = &["DASHSCOPE_API_KEY"];
 
 // Provider-specific request body size limits in bytes
@@ -80,6 +81,18 @@ impl OpenAiCompatConfig {
         }
     }
 
+    /// OpenAI-compatible endpoint with its own environment namespace and no default URL.
+    #[must_use]
+    pub const fn custom_openai() -> Self {
+        Self {
+            provider_name: "Custom OpenAI",
+            api_key_env: "CLAWCUSTOMOPENAI_API_KEY",
+            base_url_env: "CLAWCUSTOMOPENAI_BASE_URL",
+            default_base_url: "",
+            max_request_body_bytes: OPENAI_MAX_REQUEST_BODY_BYTES,
+        }
+    }
+
     /// Alibaba `DashScope` compatible-mode endpoint (Qwen family models).
     /// Uses the OpenAI-compatible REST shape at /compatible-mode/v1.
     /// Requested via Discord #clawcode-get-help: native Alibaba API for
@@ -100,6 +113,7 @@ impl OpenAiCompatConfig {
         match self.provider_name {
             "xAI" => XAI_ENV_VARS,
             "OpenAI" => OPENAI_ENV_VARS,
+            "Custom OpenAI" => CUSTOM_OPENAI_ENV_VARS,
             "DashScope" => DASHSCOPE_ENV_VARS,
             _ => &[],
         }

rust/crates/rusty-claude-cli/src/main.rs

@@ -12910,6 +12910,7 @@ fn provider_config_from_runtime(
         "anthropic" => api::ProviderConfigKind::Anthropic,
         "xai" => api::ProviderConfigKind::Xai,
         "openai" => api::ProviderConfigKind::OpenAi,
+        "custom-openai" => api::ProviderConfigKind::CustomOpenAi,
         "dashscope" => api::ProviderConfigKind::DashScope,
         other => {
             return Err(format!(
@@ -12947,6 +12948,7 @@ fn explicit_provider_kind_for_model(
         Some("anthropic") => Some(api::ProviderConfigKind::Anthropic),
         Some("xai") => Some(api::ProviderConfigKind::Xai),
         Some("openai") | Some("local") => Some(api::ProviderConfigKind::OpenAi),
+        Some("custom-openai") => Some(api::ProviderConfigKind::CustomOpenAi),
         Some("dashscope") | Some("qwen") | Some("kimi") => Some(api::ProviderConfigKind::DashScope),
         _ => {
             let lower = resolved_model.to_ascii_lowercase();
@@ -19664,6 +19666,22 @@ UU conflicted.rs",
             super::explicit_provider_kind_for_model("openai/gpt-5", &config.model),
             Some(api::ProviderConfigKind::OpenAi)
         );
+        assert_eq!(
+            super::explicit_provider_kind_for_model("custom-openai/local-model", &config.model),
+            Some(api::ProviderConfigKind::CustomOpenAi)
+        );
+        assert_eq!(
+            super::explicit_provider_kind_for_model("CUSTOM-OPENAI/local-model", &config.model),
+            Some(api::ProviderConfigKind::CustomOpenAi)
+        );
+        assert_eq!(
+            super::explicit_provider_kind_for_model(
+                "custom-openai/local-model",
+                "custom-openai/local-model"
+            ),
+            None,
+            "matching custom model must keep the persisted provider kind"
+        );
         assert_eq!(
             super::explicit_provider_kind_for_model("qwen-plus", &config.model),
             None,
@@ -19704,6 +19722,44 @@ UU conflicted.rs",
         }
     }
 
+    #[test]
+    fn persisted_custom_openai_configuration_survives_runtime_boundary() {
+        let config_home = temp_dir();
+        let workspace = temp_dir();
+        fs::create_dir_all(&config_home).expect("config home");
+        fs::create_dir_all(&workspace).expect("workspace");
+        fs::write(
+            config_home.join("settings.json"),
+            r#"{
+              "provider": {
+                "kind": "custom-openai",
+                "apiKey": "custom-test-key",
+                "baseUrl": "https://custom.example/v1",
+                "model": "local-model"
+              },
+              "model": "local-model"
+            }"#,
+        )
+        .expect("write provider settings");
+
+        let loader = ConfigLoader::new(&workspace, &config_home);
+        let runtime_config = loader.load().expect("runtime config should load");
+        let provider_config = super::provider_config_from_runtime(runtime_config.provider())
+            .expect("custom provider configuration should adapt")
+            .expect("persisted provider configuration should be present");
+
+        assert_eq!(provider_config.kind, api::ProviderConfigKind::CustomOpenAi);
+        assert_eq!(provider_config.model, "local-model");
+        assert_eq!(provider_config.api_key.as_deref(), Some("custom-test-key"));
+        assert_eq!(
+            provider_config.base_url.as_deref(),
+            Some("https://custom.example/v1")
+        );
+
+        let _ = fs::remove_dir_all(config_home);
+        let _ = fs::remove_dir_all(workspace);
+    }
+
     #[test]
     fn persisted_provider_configuration_controls_runtime_provider_dispatch() {
         let config_home = temp_dir();

rust/crates/rusty-claude-cli/src/setup_wizard.rs

@@ -9,7 +9,7 @@ const PROVIDERS: &[(&str, &str, &str)] = &[
     ("2", "xAI / Grok", "xai"),
     ("3", "OpenAI", "openai"),
     ("4", "DashScope (Qwen/Kimi)", "dashscope"),
-    ("5", "Custom (OpenAI-compat)", "openai"),
+    ("5", "Custom (OpenAI-compat)", "custom-openai"),
 ];
 
 const PROVIDER_MODELS: &[(&str, &[&str])] = &[
@@ -27,6 +27,8 @@ const DEFAULT_BASE_URLS: &[(&str, &str)] = &[
         "dashscope",
         "https://dashscope.aliyuncs.com/compatible-mode/v1",
     ),
+    // Custom OpenAI has no default; user must supply.
+    ("custom-openai", ""),
 ];
 
 const API_KEY_ENV_VARS: &[(&str, &str)] = &[
@@ -34,6 +36,7 @@ const API_KEY_ENV_VARS: &[(&str, &str)] = &[
     ("xai", "XAI_API_KEY"),
     ("openai", "OPENAI_API_KEY"),
     ("dashscope", "DASHSCOPE_API_KEY"),
+    ("custom-openai", "CLAWCUSTOMOPENAI_API_KEY"),
 ];
 
 pub fn run_setup_wizard() -> Result<(), Box<dyn std::error::Error>> {
@@ -177,6 +180,7 @@ fn prompt_base_url(
         "xai" => "XAI_BASE_URL",
         "openai" => "OPENAI_BASE_URL",
         "dashscope" => "DASHSCOPE_BASE_URL",
+        "custom-openai" => "CLAWCUSTOMOPENAI_BASE_URL",
         _ => "BASE_URL",
     };
     let env_set = std::env::var(env_var).ok().is_some_and(|v| !v.is_empty());
@@ -214,7 +218,11 @@ fn prompt_model(
     if !aliases.is_empty() {
         println!("    Common: {}", aliases.join(", "));
     }
-    println!("    Or enter any model name (e.g. openai/gpt-4.1-mini for custom routing)");
+    if kind == "custom-openai" {
+        println!("    Or enter any model name (e.g. custom/gpt-4.1 for custom routing)");
+    } else {
+        println!("    Or enter any model name (e.g. openai/gpt-4.1-mini for custom routing)");
+    }
 
     let input = read_line(&format!("  Model [{current_model}]: "))?;
     if input.trim().is_empty() {