config: apply HEXAI_* env even without config file; docs: clarify Copilot key; prefer HEXAI_COPILOT_API_KEY in builders

4 files changed, 22 insertions, 14 deletions

diff --git a/README.md b/README.md
index 28d9348..679ef05 100644
--- a/README.md
+++ b/README.md
@@ -60,7 +60,7 @@ Ensure `HEXAI_OPENAI_API_KEY` (or `OPENAI_API_KEY`) or `COPILOT_API_KEY` is set
   - `HEXAI_OLLAMA_MODEL`, `HEXAI_OLLAMA_BASE_URL`, `HEXAI_OLLAMA_TEMPERATURE`
 - API keys:
   - OpenAI: prefer `HEXAI_OPENAI_API_KEY`, falling back to `OPENAI_API_KEY`.
-  - Copilot: use `COPILOT_API_KEY`.
+  - Copilot: prefer `HEXAI_COPILOT_API_KEY`, falling back to `COPILOT_API_KEY`.
 
 ### Selecting a provider
 
diff --git a/internal/appconfig/config.go b/internal/appconfig/config.go
index 58bcc3a..6d95da2 100644
--- a/internal/appconfig/config.go
+++ b/internal/appconfig/config.go
@@ -66,18 +66,18 @@ func Load(logger *log.Logger) App {
         return cfg // Return defaults if no logger is provided (e.g. in tests)
     }
 
-	configPath, err := getConfigPath()
-	if err != nil {
-		logger.Printf("%v", err)
-		return cfg
-	}
-
-	fileCfg, err := loadFromFile(configPath, logger)
-	if err != nil {
-		return cfg
-	}
+    configPath, err := getConfigPath()
+    if err != nil {
+        logger.Printf("%v", err)
+        // Even if config path cannot be resolved, still allow env overrides below.
+    } else {
+        if fileCfg, err := loadFromFile(configPath, logger); err == nil && fileCfg != nil {
+            cfg.mergeWith(fileCfg)
+        }
+        // When the config file is missing or invalid, we keep defaults and still
+        // apply any environment overrides below.
+    }
 
-    cfg.mergeWith(fileCfg)
     // Environment overrides (take precedence over file)
     if envCfg := loadFromEnv(logger); envCfg != nil {
         cfg.mergeWith(envCfg)
diff --git a/internal/hexaicli/run.go b/internal/hexaicli/run.go
index 8cd5c82..14eff4f 100644
--- a/internal/hexaicli/run.go
+++ b/internal/hexaicli/run.go
@@ -88,7 +88,11 @@ func newClientFromConfig(cfg appconfig.App) (llm.Client, error) {
     if strings.TrimSpace(oaKey) == "" {
         oaKey = os.Getenv("OPENAI_API_KEY")
     }
-    cpKey := os.Getenv("COPILOT_API_KEY")
+    // Prefer HEXAI_COPILOT_API_KEY; fall back to COPILOT_API_KEY
+    cpKey := os.Getenv("HEXAI_COPILOT_API_KEY")
+    if strings.TrimSpace(cpKey) == "" {
+        cpKey = os.Getenv("COPILOT_API_KEY")
+    }
     return llm.NewFromConfig(llmCfg, oaKey, cpKey)
 }
 
diff --git a/internal/hexailsp/run.go b/internal/hexailsp/run.go
index 0d488f0..366d71c 100644
--- a/internal/hexailsp/run.go
+++ b/internal/hexailsp/run.go
@@ -82,7 +82,11 @@ func buildClientIfNil(cfg appconfig.App, client llm.Client) llm.Client {
     if strings.TrimSpace(oaKey) == "" {
         oaKey = os.Getenv("OPENAI_API_KEY")
     }
-    cpKey := os.Getenv("COPILOT_API_KEY")
+    // Prefer HEXAI_COPILOT_API_KEY; fall back to COPILOT_API_KEY
+    cpKey := os.Getenv("HEXAI_COPILOT_API_KEY")
+    if strings.TrimSpace(cpKey) == "" {
+        cpKey = os.Getenv("COPILOT_API_KEY")
+    }
 	if c, err := llm.NewFromConfig(llmCfg, oaKey, cpKey); err != nil {
 		logging.Logf("lsp ", "llm disabled: %v", err)
 		return nil