diff --git a/docs/getting-started.md b/docs/getting-started.md
index ade223b..fc3905d 100644
--- a/docs/getting-started.md
+++ b/docs/getting-started.md
@@ -24,9 +24,15 @@ project indexed and the MCP endpoint answering queries.
 ## Install
 
 ```bash
-go install github.com/RandomCodeSpace/docsiq@latest
+GOFLAGS='-tags=sqlite_fts5' go install github.com/RandomCodeSpace/docsiq@latest
 ```
 
+The `sqlite_fts5` build tag is required — docsiq uses SQLite's FTS5
+full-text-search extension. Without it the binary fails at runtime with
+`no such module: fts5` when opening a project store. `go install` does
+**not** pick up Makefile tags, so the flag has to come from `GOFLAGS`
+(or `-tags`) on the install command itself.
+
 This drops a `docsiq` binary into `$(go env GOPATH)/bin`. Make sure
 that path is on your `PATH`.
 
@@ -35,7 +41,7 @@ Alternatively, build from a checkout:
 ```bash
 git clone https://github.com/RandomCodeSpace/docsiq.git
 cd docsiq
-CGO_ENABLED=1 go build -o docsiq .
+CGO_ENABLED=1 go build -tags sqlite_fts5 -o docsiq .
 ```
 
 ## First project
diff --git a/internal/config/config.go b/internal/config/config.go
index 6924028..e917b91 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -273,6 +273,17 @@ func Load(cfgFile string) (*Config, error) {
 	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
 	v.AutomaticEnv()
 
+	// Bind every defaulted key to its DOCSIQ_<UPPER_KEY> env variant so
+	// v.Unmarshal honours overrides without requiring a config file.
+	// Without this, only keys explicitly listed via BindEnv are read
+	// from env when nothing in the config tree already mentions them
+	// (Viper #761). The explicit BindEnv calls below stay because they
+	// document the secondary DOCSIQ_API_KEY alias for server.api_key
+	// and harmlessly double-bind the rest.
+	for _, key := range v.AllKeys() {
+		_ = v.BindEnv(key)
+	}
+
 	// Explicit alias: DOCSIQ_API_KEY is a convenience shortcut for
 	// DOCSIQ_SERVER_API_KEY (the auth-middleware API key). Bind both so
 	// either form populates server.api_key. BindEnv names are matched
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index 856892b..5ab0744 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -719,3 +719,45 @@ func TestLoad_LogFormatFromEnv(t *testing.T) {
 		t.Errorf("env Log.Format=%q want json", cfg.Log.Format)
 	}
 }
+
+// TestLoad_EnvOverridesLLM is the regression test for the bug where
+// DOCSIQ_LLM_* env vars were silently ignored without a config file
+// because only a handful of keys were explicitly bound via BindEnv
+// (Viper #761). After the fix, every defaulted key — including the
+// nested LLM provider keys — must be reachable via env.
+func TestLoad_EnvOverridesLLM(t *testing.T) {
+	home := t.TempDir()
+	isolateEnv(t, home)
+
+	t.Setenv("DOCSIQ_LLM_OLLAMA_CHAT_MODEL", "envtest-chat")
+	t.Setenv("DOCSIQ_LLM_OLLAMA_EMBED_MODEL", "envtest-embed")
+	t.Setenv("DOCSIQ_LLM_PROVIDER", "azure")
+	t.Setenv("DOCSIQ_LLM_AZURE_API_KEY", "envtest-azure-key")
+	t.Setenv("DOCSIQ_LLM_AZURE_ENDPOINT", "https://envtest.openai.azure.com/")
+	t.Setenv("DOCSIQ_LLM_AZURE_CHAT_MODEL", "envtest-azure-chat")
+	t.Setenv("DOCSIQ_LLM_AZURE_EMBED_MODEL", "envtest-azure-embed")
+	t.Setenv("DOCSIQ_DATA_DIR", filepath.Join(home, "envtest-data"))
+
+	cfg, err := Load("")
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+
+	// Ollama keys must round-trip even when provider is azure — the
+	// fix is about *reachability* of the keys, not which one is active.
+	if got, want := cfg.LLM.Ollama.ChatModel, "envtest-chat"; got != want {
+		t.Errorf("LLM.Ollama.ChatModel = %q, want %q", got, want)
+	}
+	if got, want := cfg.LLM.Ollama.EmbedModel, "envtest-embed"; got != want {
+		t.Errorf("LLM.Ollama.EmbedModel = %q, want %q", got, want)
+	}
+	if got, want := cfg.LLM.Provider, "azure"; got != want {
+		t.Errorf("LLM.Provider = %q, want %q", got, want)
+	}
+	if got, want := cfg.LLM.Azure.APIKey, "envtest-azure-key"; got != want {
+		t.Errorf("LLM.Azure.APIKey = %q, want %q", got, want)
+	}
+	if got, want := cfg.DataDir, filepath.Join(home, "envtest-data"); got != want {
+		t.Errorf("DataDir = %q, want %q", got, want)
+	}
+}