Use messages API and system prompt

Thanks to @9j7axvsLuF for some sample code in the original issue tomviner#6

llm_claude/__init__.py

@@ -2,66 +2,76 @@
 
 import click
 import llm
-from anthropic import AI_PROMPT, HUMAN_PROMPT, Anthropic
+from anthropic import Anthropic
 from pydantic import Field, field_validator
 
-
 @llm.hookimpl
 def register_models(register):
-    # https://docs.anthropic.com/claude/reference/selecting-a-model
-    # Family           Latest major version    Latest full version
-    # Claude Instant   claude-instant-1        claude-instant-1.1
-    # Claude           claude-2                claude-2.0
-    register(Claude("claude-instant-1"), aliases=("claude-instant",))
-    register(Claude("claude-2"), aliases=("claude",))
-
+    # Registering models as per the latest naming conventions
+    register(Claude("claude-instant-1.2"), aliases=("claude-instant",))
+    register(Claude("claude-2.1"), aliases=("claude",))
 
 class Claude(llm.Model):
     needs_key = "claude"
     key_env_var = "ANTHROPIC_API_KEY"
     can_stream = True
 
     class Options(llm.Options):
-        max_tokens_to_sample: Optional[int] = Field(
-            description="The maximum number of tokens to generate before stopping",
-            default=10_000,
+        max_tokens: Optional[int] = Field(
+            description="The maximum number of tokens for the model to generate",
+            default=4096,  # Adjusted to the maximum allowed for claude-2.1
         )
 
-        @field_validator("max_tokens_to_sample")
-        def validate_length(cls, max_tokens_to_sample):
-            if not (0 < max_tokens_to_sample <= 1_000_000):
-                raise ValueError("max_tokens_to_sample must be in range 1-1,000,000")
-            return max_tokens_to_sample
+        @field_validator("max_tokens")
+        def validate_max_tokens(cls, max_tokens):
+            if not (0 < max_tokens <= 4096):  # Updated maximum limit
+                raise ValueError("max_tokens must be in range 1-4096 for claude-2.1")
+            return max_tokens
 
     def __init__(self, model_id):
         self.model_id = model_id
 
     def generate_prompt_messages(self, prompt, conversation):
-        if conversation:
-            for response in conversation.responses:
-                yield self.build_prompt(response.prompt.prompt, response.text())
-
-        yield self.build_prompt(prompt)
-
-    def build_prompt(self, human, ai=""):
-        return f"{HUMAN_PROMPT} {human}{AI_PROMPT}{ai}"
+        # Generate a list of message dictionaries based on conversation history
+        messages = []
+        current_system = None
+        if conversation is not None:
+            for prev_response in conversation.responses:
+                if (prev_response.prompt.system and prev_response.prompt.system != current_system):
+                    current_system = prev_response.prompt.system
+                messages.append({"role": "user", "content": prev_response.prompt.prompt})
+                messages.append({"role": "assistant", "content": prev_response.text()})
+        if prompt.system and prompt.system != current_system:
+            current_system = prompt.system
+        messages.append({"role": "user", "content": prompt.prompt})
+
+        return messages, current_system
 
     def execute(self, prompt, stream, response, conversation):
         anthropic = Anthropic(api_key=self.get_key())
 
-        prompt_str = "".join(self.generate_prompt_messages(prompt.prompt, conversation))
+        messages, system_prompt = self.generate_prompt_messages(prompt, conversation)
 
-        completion = anthropic.completions.create(
-            model=self.model_id,
-            max_tokens_to_sample=prompt.options.max_tokens_to_sample,
-            prompt=prompt_str,
-            stream=stream,
-        )
         if stream:
-            for comp in completion:
-                yield comp.completion
+            # Handling streaming responses
+            with anthropic.beta.messages.stream(
+                max_tokens=prompt.options.max_tokens,
+                messages=messages,
+                system=system_prompt,
+                model=self.model_id
+            ) as stream_response:
+                for text in stream_response.text_stream:
+                    yield text
         else:
-            yield completion.completion
+            # Handling non-streaming response
+            message_response = anthropic.beta.messages.create(
+                model=self.model_id,
+                max_tokens=prompt.options.max_tokens,
+                messages=messages,
+                system=system_prompt
+            )
+            # Concatenating text from content blocks
+            yield "".join(content_block['text'] for content_block in message_response.content)
 
     def __str__(self):
         return "Anthropic: {}".format(self.model_id)