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https://github.com/meta-llama/llama-stack.git
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This is a sweeping change to clean up some gunk around our "Tool" definitions. First, we had two types `Tool` and `ToolDef`. The first of these was a "Resource" type for the registry but we had stopped registering tools inside the Registry long back (and only registered ToolGroups.) The latter was for specifying tools for the Agents API. This PR removes the former and adds an optional `toolgroup_id` field to the latter. Secondly, as pointed out by @bbrowning in https://github.com/llamastack/llama-stack/pull/3003#issuecomment-3245270132, we were doing a lossy conversion from a full JSON schema from the MCP tool specification into our ToolDefinition to send it to the model. There is no necessity to do this -- we ourselves aren't doing any execution at all but merely passing it to the chat completions API which supports this. By doing this (and by doing it poorly), we encountered limitations like not supporting array items, or not resolving $refs, etc. To fix this, we replaced the `parameters` field by `{ input_schema, output_schema }` which can be full blown JSON schemas. Finally, there were some types in our llama-related chat format conversion which needed some cleanup. We are taking this opportunity to clean those up. This PR is a substantial breaking change to the API. However, given our window for introducing breaking changes, this suits us just fine. I will be landing a concurrent `llama-stack-client` change as well since API shapes are changing.
286 lines
10 KiB
Python
286 lines
10 KiB
Python
# Copyright (c) Meta Platforms, Inc. and affiliates.
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# All rights reserved.
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#
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# This source code is licensed under the terms described in the LICENSE file in
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# the root directory of this source tree.
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import io
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import json
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import uuid
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from dataclasses import dataclass
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from typing import Any
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from PIL import Image as PIL_Image
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from ..datatypes import (
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BuiltinTool,
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RawContent,
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RawMediaItem,
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RawMessage,
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RawTextItem,
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Role,
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StopReason,
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ToolCall,
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ToolPromptFormat,
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)
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from .tokenizer import Tokenizer
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from .tool_utils import ToolUtils
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@dataclass
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class VisionInput:
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mask: list[list[int]]
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images: list[PIL_Image.Image]
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@dataclass
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class LLMInput:
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tokens: list[int]
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vision: VisionInput | None = None
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def role_str(role: Role) -> str:
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role_strs = {
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Role.user: "user",
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Role.system: "system",
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Role.tool: "ipython", # special
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Role.assistant: "assistant",
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}
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return role_strs[role]
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class ChatFormat:
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possible_headers: dict[Role, str]
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def __init__(self, tokenizer: Tokenizer):
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self.tokenizer = tokenizer
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self.possible_headers = {role: f"<|start_header_id|>{role_str(role)}<|end_header_id|>\n\n" for role in Role}
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self.vision_token = self.tokenizer.special_tokens["<|image|>"]
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def _encode_header(self, role: str) -> list[int]:
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tokens = []
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tokens.append(self.tokenizer.special_tokens["<|start_header_id|>"])
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tokens.extend(self.tokenizer.encode("ipython" if role == "tool" else role, bos=False, eos=False))
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tokens.append(self.tokenizer.special_tokens["<|end_header_id|>"])
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tokens.extend(self.tokenizer.encode("\n\n", bos=False, eos=False))
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return tokens
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def encode_content(self, content: RawContent) -> LLMInput:
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tokens, images = self._encode_content(content, bos=True)
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return self._model_input_from_tokens_images(tokens, images)
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def _encode_content(self, content: RawContent, bos: bool = False) -> tuple[list[int], list[PIL_Image.Image]]:
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tokens = []
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images = []
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added_bos = False
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def _process(c):
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nonlocal added_bos, bos
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if isinstance(c, str) or isinstance(c, RawTextItem):
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if isinstance(c, RawTextItem):
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c = c.text
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tokens.extend(self.tokenizer.encode(c, bos=False if added_bos else bos, eos=False))
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added_bos = True
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elif isinstance(c, RawMediaItem):
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bos = False if added_bos else bos
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if bos:
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tokens.append(self.tokenizer.special_tokens["<|begin_of_text|>"])
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added_bos = True
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tokens.append(self.vision_token)
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bytes_io = io.BytesIO(c.data) if isinstance(c.data, bytes) else c.data
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image = PIL_Image.open(bytes_io)
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image = image.convert("RGB")
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images.append(image)
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if isinstance(content, list):
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for c in content:
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_process(c)
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else:
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_process(content)
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return tokens, images
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def encode_message(
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self, message: RawMessage, tool_prompt_format: ToolPromptFormat
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) -> tuple[list[int], list[PIL_Image.Image]]:
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tokens = self._encode_header(message.role)
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images = []
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def _process_content(c):
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toks, imgs = self._encode_content(c)
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tokens.extend(toks)
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images.extend(imgs)
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if (
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message.role == "assistant"
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and len(message.tool_calls) > 0
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and message.tool_calls[0].tool_name == BuiltinTool.code_interpreter
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):
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tokens.append(self.tokenizer.special_tokens["<|python_tag|>"])
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_process_content(message.content)
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if message.role == "user" and message.context is not None:
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# This is RAG context; why is it here in the chat format? I don't think
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# this is needed and can be moved upwards
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_process_content("\n\n")
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_process_content(message.context)
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if message.role == "assistant":
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for t in message.tool_calls:
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content = ToolUtils.encode_tool_call(t, tool_prompt_format)
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_process_content(content)
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eom = False
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if message.role == "assistant":
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eom = message.stop_reason == StopReason.end_of_message
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tokens.append(self.tokenizer.special_tokens["<|eom_id|>" if eom else "<|eot_id|>"])
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return tokens, images
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def encode_dialog_prompt(
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self,
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messages: list[RawMessage],
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tool_prompt_format: ToolPromptFormat | None = None,
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) -> LLMInput:
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tool_prompt_format = tool_prompt_format or ToolPromptFormat.json
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tokens = []
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images = []
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tokens.append(self.tokenizer.special_tokens["<|begin_of_text|>"])
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for message in messages:
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toks, imgs = self.encode_message(message, tool_prompt_format)
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tokens.extend(toks)
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images.extend(imgs)
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# Add the start of an assistant message for the model to complete.
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tokens.extend(self._encode_header("assistant"))
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return self._model_input_from_tokens_images(tokens, images)
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# TODO(this should be generic, not only for assistant messages)
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def decode_assistant_message(self, tokens: list[int], stop_reason: StopReason) -> RawMessage:
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content = self.tokenizer.decode(tokens)
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return self.decode_assistant_message_from_content(content, stop_reason)
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def decode_assistant_message_from_content(self, content: str, stop_reason: StopReason) -> RawMessage:
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content = content.strip(" ")
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header_str = self.possible_headers[Role.assistant]
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if content.startswith(header_str):
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content = content[len(header_str) :]
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ipython = content.startswith("<|python_tag|>")
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if ipython:
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content = content[len("<|python_tag|>") :]
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if content.endswith("<|eot_id|>"):
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content = content[: -len("<|eot_id|>")]
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stop_reason = StopReason.end_of_turn
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elif content.endswith("<|eom_id|>"):
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content = content[: -len("<|eom_id|>")]
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stop_reason = StopReason.end_of_message
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tool_name: str | BuiltinTool | None = None
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tool_arguments: dict[str, Any] = {}
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custom_tool_info = ToolUtils.maybe_extract_custom_tool_call(content)
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if custom_tool_info is not None:
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# Type guard: ensure custom_tool_info is a tuple of correct types
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if isinstance(custom_tool_info, tuple) and len(custom_tool_info) == 2:
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extracted_tool_name, extracted_tool_arguments = custom_tool_info
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# Handle both dict and str return types from the function
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if isinstance(extracted_tool_arguments, dict):
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tool_name, tool_arguments = extracted_tool_name, extracted_tool_arguments
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else:
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# If it's a string, treat it as a query parameter
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tool_name, tool_arguments = extracted_tool_name, {"query": extracted_tool_arguments}
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else:
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tool_name, tool_arguments = None, {}
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# Sometimes when agent has custom tools alongside builin tools
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# Agent responds for builtin tool calls in the format of the custom tools
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# This code tries to handle that case
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if tool_name is not None and tool_name in BuiltinTool.__members__:
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tool_name = BuiltinTool[tool_name]
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if isinstance(tool_arguments, dict):
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tool_arguments = {
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"query": list(tool_arguments.values())[0],
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}
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else:
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builtin_tool_info = ToolUtils.maybe_extract_builtin_tool_call(content)
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if builtin_tool_info is not None:
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tool_name, query = builtin_tool_info
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tool_arguments = {
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"query": query,
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}
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if tool_name in BuiltinTool.__members__:
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tool_name = BuiltinTool[tool_name]
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elif ipython:
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tool_name = BuiltinTool.code_interpreter
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tool_arguments = {
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"code": content,
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}
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tool_calls = []
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if tool_name is not None and tool_arguments is not None:
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call_id = str(uuid.uuid4())
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tool_calls.append(
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ToolCall(
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call_id=call_id,
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tool_name=tool_name,
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arguments=json.dumps(tool_arguments),
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)
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)
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content = ""
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return RawMessage(
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role="assistant",
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content=content,
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stop_reason=stop_reason,
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tool_calls=tool_calls,
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)
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def _model_input_from_tokens_images(self, tokens: list[int], images: list[PIL_Image.Image]) -> LLMInput:
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vision_input = None
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if len(images) > 0:
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vision_input = VisionInput(
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mask=create_vision_mask(tokens, self.vision_token),
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images=images,
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)
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return LLMInput(
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tokens=[128256 if token == self.vision_token else token for token in tokens],
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vision=vision_input,
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)
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def create_vision_mask(
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tokens: list[int],
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vision_token: int,
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) -> list[list[int]]:
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vision_token_locations = [i for i, token in enumerate(tokens) if token == vision_token]
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if len(vision_token_locations) == 0:
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return []
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if len(vision_token_locations) == 1:
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# only one image present, unmask until end of sequence
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return [[vision_token_locations[0], -1]]
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vision_masks = [
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[loc1, loc2] for loc1, loc2 in zip(vision_token_locations[:-1], vision_token_locations[1:], strict=False)
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]
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# last image will attend to all subsequent text
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vision_masks.append([vision_token_locations[-1], len(tokens)])
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# if there are two or more consecutive vision tokens,
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# they should all attend to all subsequent
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# text present
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last_mask_end = vision_masks[-1][1]
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for vision_mask in vision_masks[::-1]:
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if vision_mask[0] == vision_mask[1] - 1:
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vision_mask[1] = last_mask_end
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last_mask_end = vision_mask[1]
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return vision_masks
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