diff --git a/src/chap/backends/anthropic.py b/src/chap/backends/anthropic.py
index 486db4d..f3d8f41 100644
--- a/src/chap/backends/anthropic.py
+++ b/src/chap/backends/anthropic.py
@@ -17,7 +17,7 @@ class Anthropic(AutoAskMixin):
     @dataclass
     class Parameters:
         url: str = "https://api.anthropic.com"
-        model: str = "claude-3-sonnet-20240229"
+        model: str = "claude-3-5-sonnet-20240620"
         max_new_tokens: int = 1000
 
     def __init__(self) -> None:
@@ -94,5 +94,5 @@ Answer each question accurately and thoroughly.
 
 
 def factory() -> Backend:
-    """Uses the huggingface text-generation-interface web API"""
+    """Uses the anthropic text-generation-interface web API"""
     return Anthropic()
diff --git a/src/chap/backends/llama_cpp.py b/src/chap/backends/llama_cpp.py
index 99ddece..5cb92cb 100644
--- a/src/chap/backends/llama_cpp.py
+++ b/src/chap/backends/llama_cpp.py
@@ -18,10 +18,16 @@ class LlamaCpp(AutoAskMixin):
         url: str = "http://localhost:8080/completion"
         """The URL of a llama.cpp server's completion endpoint."""
 
-        start_prompt: str = "<s>"
-        system_format: str = "<<SYS>>{}<</SYS>>"
-        user_format: str = " [INST] {} [/INST]"
-        assistant_format: str = " {}</s>"
+        start_prompt: str = "<|begin_of_text|>"
+        system_format: str = (
+            "<|start_header_id|>system<|end_header_id|>\n\n{}<|eot_id|>"
+        )
+        user_format: str = "<|start_header_id|>user<|end_header_id|>\n\n{}<|eot_id|>"
+        assistant_format: str = (
+            "<|start_header_id|>assistant<|end_header_id|>\n\n{}<|eot_id|>"
+        )
+        end_prompt: str = "<|start_header_id|>assistant<|end_header_id|>\n\n"
+        stop: str | None = None
 
     def __init__(self) -> None:
         super().__init__()
@@ -59,7 +65,7 @@ A dialog, where USER interacts with AI. AI is helpful, kind, obedient, honest, a
         params = {
             "prompt": self.make_full_query(session + [User(query)], max_query_size),
             "stream": True,
-            "stop": ["</s>", "<s>", "[INST]"],
+            "stop": ["</s>", "<s>", "[INST]", "<|eot_id|>"],
         }
         new_content: list[str] = []
         try:
diff --git a/src/chap/core.py b/src/chap/core.py
index 9a3df7f..67ed9f7 100644
--- a/src/chap/core.py
+++ b/src/chap/core.py
@@ -129,7 +129,11 @@ def configure_api_from_environment(
         setattr(api.parameters, field.name, tv)
 
 
-def get_api(ctx: click.Context, name: str = "openai_chatgpt") -> Backend:
+def get_api(ctx: click.Context | None = None, name: str | None = None) -> Backend:
+    if ctx is None:
+        ctx = click.Context(click.Command("chap"))
+    if name is None:
+        name = os.environ.get("CHAP_BACKEND", "openai_chatgpt")
     name = name.replace("-", "_")
     backend = cast(
         Backend, importlib.import_module(f"{__package__}.backends.{name}").factory()