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seed_0/Qwen/Qwen2.5-7B-Instruct/adapters/critic_adapter/adapter_config.json

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+{
+  "alora_invocation_tokens": null,
+  "alpha_pattern": {},
+  "arrow_config": null,
+  "auto_mapping": null,
+  "base_model_name_or_path": "Qwen/Qwen2.5-7B-Instruct",
+  "bias": "none",
+  "corda_config": null,
+  "ensure_weight_tying": false,
+  "eva_config": null,
+  "exclude_modules": null,
+  "fan_in_fan_out": false,
+  "inference_mode": true,
+  "init_lora_weights": true,
+  "layer_replication": null,
+  "layers_pattern": null,
+  "layers_to_transform": null,
+  "loftq_config": {},
+  "lora_alpha": 64,
+  "lora_bias": false,
+  "lora_dropout": 0.0,
+  "megatron_config": null,
+  "megatron_core": "megatron.core",
+  "modules_to_save": null,
+  "peft_type": "LORA",
+  "peft_version": "0.18.1",
+  "qalora_group_size": 16,
+  "r": 32,
+  "rank_pattern": {},
+  "revision": null,
+  "target_modules": [
+    "v_proj",
+    "gate_proj",
+    "o_proj",
+    "k_proj",
+    "up_proj",
+    "down_proj",
+    "q_proj"
+  ],
+  "target_parameters": null,
+  "task_type": "CAUSAL_LM",
+  "trainable_token_indices": null,
+  "use_dora": false,
+  "use_qalora": false,
+  "use_rslora": false
+}

src_code_for_reproducibility/chat_utils/apply_template.py

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+"""
+File: mllm/chat_utils/apply_template.py
+Summary: Applies tokenizer-specific chat templates and stitches chat token IDs.
+"""
+
+import torch
+
+from mllm.chat_utils.chat_turn import ChatTurn
+from mllm.chat_utils.template_specific import (
+    custom_gemma3_template,
+    custom_llama3_template,
+    custom_qwen2_template,
+    custom_qwen3_template,
+    gemma3_assistant_postfix,
+    qwen2_assistant_postfix,
+    qwen3_assistant_postfix,
+)
+
+
+def get_custom_chat_template(tokenizer) -> str:
+    """
+    Get the chat template for the tokenizer.
+    """
+    if "qwen2" in tokenizer.name_or_path.lower():
+        return custom_qwen2_template
+    elif "llama" in tokenizer.name_or_path.lower():
+        return custom_llama3_template
+    elif "qwen3" in tokenizer.name_or_path.lower():
+        return custom_qwen3_template
+    elif "gemma" in tokenizer.name_or_path.lower():
+        return custom_gemma3_template
+    else:
+        raise ValueError(f"Tokenizer {tokenizer.name_or_path} not supported")
+
+
+def get_custom_assistant_postfix(tokenizer) -> torch.Tensor:
+    """
+    Get the custom assistant postfix for the tokenizer.
+    """
+    if "qwen2" in tokenizer.name_or_path.lower():
+        return qwen2_assistant_postfix
+    elif "qwen3" in tokenizer.name_or_path.lower():
+        return qwen3_assistant_postfix
+    elif "gemma" in tokenizer.name_or_path.lower():
+        return gemma3_assistant_postfix
+    return torch.tensor([], dtype=torch.long)
+
+
+def tokenize_chats(chats: list[ChatTurn], tokenizer, enable_thinking) -> None:
+    """
+    Set the chat_template_token_ids for each chat turn.
+    We rely on tokenizer-side templates because engine-provided cached tokens are not exposed yet.
+    """
+    custom_template = get_custom_chat_template(tokenizer)
+    custom_assistant_postfix: torch.Tensor = get_custom_assistant_postfix(tokenizer)
+    for i, chat in enumerate(chats):
+        if chat.chat_template_token_ids is None:
+            if chat.role == "user":
+                next_chat = chats[i + 1] if i + 1 < len(chats) else None
+                add_generation_prompt = True
+                if next_chat and next_chat.role == "user":
+                    add_generation_prompt = False
+                encoded_chat = tokenizer.apply_chat_template(
+                    [chat],
+                    return_tensors="pt",
+                    chat_template=custom_template,
+                    add_generation_prompt=add_generation_prompt,
+                    add_system_prompt=True if i == 0 else False,
+                    enable_thinking=enable_thinking,
+                ).flatten()
+                previous_chat = chats[i - 1] if i > 0 else None
+                if previous_chat and previous_chat.role == "assistant":
+                    encoded_chat = torch.cat([custom_assistant_postfix, encoded_chat])
+            elif chat.role == "assistant":
+                encoded_chat = chat.out_token_ids
+            chat.chat_template_token_ids = encoded_chat
+
+
+def chat_turns_to_token_ids(
+    chats: list[ChatTurn], tokenizer, enable_thinking
+) -> list[int]:
+    """
+    Tokenize the chat turns and set the chat_template_token_ids for each chat turn.
+    """
+    tokenize_chats(chats=chats, tokenizer=tokenizer, enable_thinking=enable_thinking)
+    token_ids = []
+    for chat in chats:
+        token_ids.append(chat.chat_template_token_ids)
+    return torch.cat(token_ids)

src_code_for_reproducibility/chat_utils/chat_turn.py

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+"""
+File: mllm/chat_utils/chat_turn.py
+Summary: Defines the ChatTurn schema plus helpers for serialization and validation.
+"""
+
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any, List, Literal, Optional, Tuple
+
+import jsonschema
+import torch
+from pydantic import BaseModel, ConfigDict, Field, model_validator
+
+AgentId = str
+
+
+class ChatTurn(BaseModel):
+    model_config = ConfigDict(arbitrary_types_allowed=True)  # needed for torch tensors
+
+    role: str = Field(pattern="^(user|assistant)$")
+    agent_id: AgentId  # ID of the agent with which the chat occured
+    content: str
+    reasoning_content: str | None = None
+    chat_template_token_ids: torch.LongTensor | None = None  # Token ids of chat template format. For example, token ids of "<assistant>{content}</assistant>""
+    out_token_ids: torch.LongTensor | None = (
+        None  # tokens generated from inference engine
+    )
+    log_probs: torch.FloatTensor | None = None
+    is_state_end: bool = False  # indicates whether this chat turn marks the end of a state in the trajectory

src_code_for_reproducibility/chat_utils/template_specific.py

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+"""
+File: mllm/chat_utils/template_specific.py
+Summary: Stores chat template variants and assistant postfix tensors per tokenizer.
+"""
+
+import huggingface_hub
+import torch
+from transformers import AutoTokenizer
+
+custom_llama3_template = """
+{%- if add_system_prompt %}
+    {{- '<|begin_of_text|><|start_header_id|>system<|end_header_id|>\n\nCutting Knowledge Date: December 2023\nToday Date: 26 Jul 2024\n\n<|eot_id|>' }}
+{%- endif %}
+{%- for message in messages %}
+    {{- '<|start_header_id|>' + message['role'] + '<|end_header_id|>\n\n' + message['content'] | trim + '<|eot_id|>' }}
+{%- endfor %}
+
+{%- if add_generation_prompt %}
+    {{- '<|start_header_id|>' + 'assistant' + '<|end_header_id|>\n\n' }}
+{%- endif %}
+"""
+
+qwen2_assistant_postfix = (
+    AutoTokenizer.from_pretrained("Qwen/Qwen2.5-7B-Instruct")
+    .encode("\n", return_tensors="pt")
+    .flatten()
+)
+qwen3_assistant_postfix = (
+    AutoTokenizer.from_pretrained("Qwen/Qwen3-8B")
+    .encode("\n", return_tensors="pt")
+    .flatten()
+)
+gemma3_assistant_postfix = (
+    AutoTokenizer.from_pretrained("google/gemma-3-4b-it")
+    .encode("\n", return_tensors="pt")
+    .flatten()
+)
+custom_qwen2_template = """
+{%- if add_system_prompt %}
+    {{- '<|im_start|>system\nYou are Qwen, created by Alibaba Cloud. You are a helpful assistant.<|im_end|>\n' }}
+{%- endif %}
+{%- set ns = namespace(multi_step_tool=true, last_query_index=messages|length - 1) %}
+{%- for message in messages %}
+    {%- if message.content is string %}
+        {%- set content = message.content %}
+    {%- else %}
+        {%- set content = '' %}
+    {%- endif %}
+    {%- if (message.role == "user") %}
+        {{- '<|im_start|>' + message.role + '\n' + content + '<|im_end|>' + '\n' }}
+    {%- elif message.role == "assistant" %}
+        {%- set reasoning_content = '' %}
+        {%- if message.reasoning_content is string %}
+            {%- set reasoning_content = message.reasoning_content %}
+        {%- else %}
+            {%- if '</think>' in content %}
+                {%- set reasoning_content = content.split('</think>')[0].rstrip('\n').split('<think>')[-1].lstrip('\n') %}
+                {%- set content = content.split('</think>')[-1].lstrip('\n') %}
+            {%- endif %}
+        {%- endif %}
+        {%- if loop.index0 > ns.last_query_index %}
+            {%- if reasoning_content %}
+                {{- '<|im_start|>' + message.role + '\n<think>\n' + reasoning_content.strip('\n') + '\n</think>\n\n' + content.lstrip('\n') }}
+            {%- else %}
+                {{- '<|im_start|>' + message.role + '\n' + content }}
+            {%- endif %}
+        {%- else %}
+            {{- '<|im_start|>' + message.role + '\n' + content }}
+        {%- endif %}
+        {{- '<|im_end|>\n' }}
+    {%- endif %}
+{%- endfor %}
+{%- if add_generation_prompt %}
+    {{- '<|im_start|>assistant\n' }}
+{%- endif %}
+"""
+
+custom_qwen3_template = """
+{%- for message in messages %}
+    {%- if message.content is string %}
+        {%- set content = message.content %}
+    {%- else %}
+        {%- set content = '' %}
+    {%- endif %}
+    {%- if (message.role == "user") %}
+        {{- '<|im_start|>' + message.role + '\n' + content + '<|im_end|>' + '\n' }}
+    {%- elif message.role == "assistant" %}
+        {{- '<|im_start|>' + message.role + '\n' + content + '<|im_end|>' + '\n' }}
+    {%- endif %}
+{%- endfor %}
+{%- if add_generation_prompt %}
+    {{- '<|im_start|>assistant\n' }}
+    {%- if enable_thinking is defined and enable_thinking is false %}
+        {{- '<think>\n\n</think>\n\n' }}
+    {%- endif %}
+{%- endif %}
+"""
+
+custom_gemma3_template = """
+{%- if add_system_prompt %}
+{{- bos_token -}}
+{%- endif %}
+{%- for message in messages -%}
+{%- if message['role'] == 'assistant' -%}
+{%- set role = 'model' -%}
+{%- else -%}
+{%- set role = message['role'] -%}
+{%- endif -%}
+{{ '<start_of_turn>' + role + '\n' + message['content'] | trim + '<end_of_turn>\n' }}
+{%- endfor -%}
+{%- if add_generation_prompt -%}
+{{ '<start_of_turn>model\n' }}
+{%- endif -%}
+"""

src_code_for_reproducibility/markov_games/__init__.py

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+"""
+File: mllm/markov_games/__init__.py
+Summary: Makes Markov-game subpackages importable from the top-level namespace.
+"""

src_code_for_reproducibility/markov_games/agent.py

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+"""
+File: mllm/markov_games/agent.py
+Summary: Declares the base Agent interface connecting simulations to policy calls.
+"""
+
+from abc import ABC, abstractmethod
+from collections.abc import Callable
+from typing import Any, Tuple
+
+from numpy.random import default_rng
+
+from mllm.markov_games.rollout_tree import AgentActLog
+
+
+class Agent(ABC):
+    """Abstract policy wrapper that bridges simulations with arbitrary backends."""
+
+    @abstractmethod
+    def __init__(
+        self,
+        seed: int,
+        agent_id: str,
+        agent_name: str,
+        agent_policy: Callable[[list[dict]], str],
+        *args,
+        **kwargs,
+    ):
+        """
+        Initialize the agent state and seed its RNG.
+
+        Subclasses typically store extra handles (tokenizers, inference clients, etc.)
+        but they should always call ``super().__init__`` so sampling remains reproducible.
+        """
+        self.seed = seed
+        self.agent_id = agent_id
+        self.agent_name = agent_name
+        self.policy = policy
+        self.rng = default_rng(self.seed)
+        raise NotImplementedError
+
+    async def act(self, observation) -> Tuple[Any, AgentActLog]:
+        """
+        Produce the next action (and associated chat log) given an environment observation.
+
+        Implementations can iterate with rejection sampling, multi-call deliberation, etc.
+        Returns both the chosen action and an `AgentActLog` describing how it was produced.
+        """
+        raise NotImplementedError
+
+    def get_safe_copy(self):
+        """
+        Return a deep copy whose future calls do not mutate the original agent.
+
+        Needed for branch exploration/reruns with alternative actions.
+        """
+        raise NotImplementedError
+
+    def reset(self):
+        """Reset any internal state between rollouts."""
+        raise NotImplementedError
+
+    def render(self):
+        """Optional human-readable visualization of the agent (CLI/UI)."""
+        raise NotImplementedError
+
+    def close(self):
+        """Release any external resources (network sockets, subprocesses, etc.)."""
+        raise NotImplementedError
+
+    def get_agent_info(self):
+        """Return diagnostic metadata to embed inside rollout logs."""
+        raise NotImplementedError

src_code_for_reproducibility/markov_games/alternative_actions_runner.py

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+"""
+File: mllm/markov_games/alternative_actions_runner.py
+Summary: Generates rollout branches by replaying trajectories with unilateral action changes.
+"""
+
+import asyncio
+import copy
+import json
+import os.path
+from typing import Any, Tuple
+
+from mllm.markov_games.markov_game import AgentAndActionSafeCopy, MarkovGame
+from mllm.markov_games.rollout_tree import (
+    AgentActLog,
+    RolloutTreeBranchNode,
+    RolloutTreeNode,
+    RolloutTreeRootNode,
+    StepLog,
+)
+
+AgentId = str
+
+
+async def run_with_unilateral_alt_action(
+    markov_game: MarkovGame,
+    agent_id: AgentId,
+    time_step: int,
+    branch_node: RolloutTreeBranchNode,
+    max_depth: int,
+):
+    """
+    Roll out a counterfactual branch where ``agent_id`` deviates unilaterally.
+
+    Starting from ``branch_node`` (which already contains the main trajectory),
+    we replay the simulation with the deviating agent's action while freezing
+    all other agents/actions, then continue for ``max_depth`` steps.
+    """
+
+    # Generate alternative action and take a step
+    await markov_game.set_action_of_agent(agent_id)
+    terminated: bool = markov_game.take_simulation_step()
+    step_log = markov_game.get_step_log()
+    first_alternative_node = RolloutTreeNode(
+        step_log=step_log,
+        time_step=time_step,
+    )
+
+    # Generate rest of trajectory up to max depth
+    time_step += 1
+    counter = 1
+    previous_node = first_alternative_node
+    while not terminated and counter <= max_depth:
+        terminated, step_log = await markov_game.step()
+        current_node = RolloutTreeNode(step_log=step_log, time_step=time_step)
+        previous_node.child = current_node
+        previous_node = current_node
+        counter += 1
+        time_step += 1
+
+    if branch_node.branches == None:
+        branch_node.branches = {agent_id: [first_alternative_node]}
+    else:
+        agent_branches = branch_node.branches.get(agent_id, [])
+        agent_branches.append(first_alternative_node)
+        branch_node.branches[agent_id] = agent_branches
+
+
+async def AlternativeActionsRunner(
+    markov_game: MarkovGame,
+    output_folder: str,
+    nb_alternative_actions: int,
+    max_depth: int,
+    branch_only_on_new_round: bool = False,
+):
+    """
+    Generate a rollout tree containing the main path plus unilateral deviation branches.
+
+    For each timestep we:
+      1. Cache agent actions without side effects.
+      2. Advance the main trajectory.
+      3. Spawn ``nb_alternative_actions`` asynchronous deviations per agent,
+         each replaying up to ``max_depth`` steps from the cached pre-action state.
+    The resulting branches feed advantage-alignment estimators.
+    """
+
+    tasks = []
+    time_step = 0
+    terminated = False
+    root = RolloutTreeRootNode(id=markov_game.get_id(), crn_id=markov_game.get_crn_id())
+    previous_node = root
+
+    while not terminated:
+        mg_before_action = markov_game.get_safe_copy()
+
+        # Get safe copies for main branch
+        agent_action_safe_copies: dict[
+            AgentId, AgentAndActionSafeCopy
+        ] = await markov_game.get_actions_of_agents_without_side_effects()
+
+        markov_game.set_actions_of_agents_manually(agent_action_safe_copies)
+        terminated = markov_game.take_simulation_step()
+        main_node = RolloutTreeNode(
+            step_log=markov_game.get_step_log(), time_step=time_step
+        )
+        branch_node = RolloutTreeBranchNode(main_child=main_node)
+        previous_node.child = branch_node
+        previous_node = main_node
+
+        # Get alternative branches by generating new unilateral actions
+        for agent_id in markov_game.agent_ids:
+            for _ in range(nb_alternative_actions):
+                # Get safe copies for branches
+                branch_agent_action_safe_copies: dict[
+                    AgentId, AgentAndActionSafeCopy
+                ] = {
+                    agent_id: AgentAndActionSafeCopy(
+                        action=copy.deepcopy(agent_action_safe_copy.action),
+                        action_info=copy.deepcopy(agent_action_safe_copy.action_info),
+                        agent_after_action=agent_action_safe_copy.agent_after_action.get_safe_copy(),
+                    )
+                    for agent_id, agent_action_safe_copy in agent_action_safe_copies.items()
+                }
+                mg_branch: MarkovGame = mg_before_action.get_safe_copy()
+                other_agent_id = [id for id in mg_branch.agent_ids if id != agent_id][0]
+                mg_branch.set_action_and_agent_after_action_manually(
+                    agent_id=other_agent_id,
+                    agent_action_safe_copy=branch_agent_action_safe_copies[
+                        other_agent_id
+                    ],
+                )
+                task = asyncio.create_task(
+                    run_with_unilateral_alt_action(
+                        markov_game=mg_branch,
+                        time_step=time_step,
+                        agent_id=agent_id,
+                        branch_node=branch_node,
+                        max_depth=max_depth,
+                    )
+                )
+                tasks.append(task)
+        time_step += 1
+
+    # wait for all branches to complete
+    await asyncio.gather(*tasks)
+
+    return root

src_code_for_reproducibility/markov_games/group_timesteps.py

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+"""
+File: mllm/markov_games/group_timesteps.py
+Summary: Provides timestep-grouping utilities for rollout trees and training.
+"""
+
+import copy
+from typing import Callable
+
+from mllm.markov_games.markov_game import MarkovGame
+from mllm.markov_games.rollout_tree import (
+    AgentActLog,
+    RolloutTreeBranchNode,
+    RolloutTreeNode,
+    RolloutTreeRootNode,
+    StepLog,
+)
+from mllm.markov_games.simulation import SimulationStepLog
+
+AgentId = str
+
+
+def group_time_steps(
+    rollout_tree: RolloutTreeRootNode,
+    accumulation_stop_condition: Callable[[StepLog], bool],
+) -> RolloutTreeRootNode:
+    """
+    During generation, we create rollout trees according to the real time steps.
+    However, during training, we might want to treat groups of time steps as a single time step.
+    As a concrete example, take Trust-and-Split. At each round, say we have X time steps of communication and then one time step for the split.
+    Then the communication actions will not get any reward, and the split action will get the reward. During REINFORCE training, with discounting, this
+    can cause training instability. We could instead treat every action in the round as being part of a single action, and give it the reward of the split action.
+    This method helps to do this sort of grouping.
+    It accumulates actions until the accumulation_stop_condition is met, and then creates a new node with the accumulated actions.
+    It then recursively calls itself on the child node.
+    Details:
+    - The reward for the group is the reward of the last time step in the group.
+    - The simulation log for the group is the simulation log of the last time step in the group.
+    - The state end for the group becomes the first state end in the group.
+    - The agent info for the group is the agent info of the last time step in the group.
+    """
+
+    def group_step_logs(step_logs: list[StepLog]) -> StepLog:
+        """
+        Concatenate per-agent chat turns across steps; keep only the first is_state_end.
+        """
+        last_sim_log = step_logs[-1].simulation_step_log
+        agent_ids = {aid for s in step_logs for aid in s.action_logs.keys()}
+        grouped_logs: dict[AgentId, AgentActLog] = {}
+        for aid in agent_ids:
+            turns = []
+            for s in step_logs:
+                act = s.action_logs.get(aid)
+                if act and act.chat_turns:
+                    turns.extend(copy.deepcopy(act.chat_turns))
+            disable_is_state_end = False
+            # Only the first state_end should be True, the rest should be False
+            for t in turns:
+                if t.is_state_end:
+                    if disable_is_state_end:
+                        t.is_state_end = False
+                    else:
+                        disable_is_state_end = True
+                    continue
+            grouped_logs[aid] = AgentActLog(
+                chat_turns=turns, info=step_logs[-1].action_logs[aid].info
+            )
+        return StepLog(action_logs=grouped_logs, simulation_step_log=last_sim_log)
+
+    def group_time_steps_rec(
+        current_node: RolloutTreeNode | RolloutTreeBranchNode,
+        group_time_step: int,
+        accumulation_step_logs: list[StepLog],
+    ) -> RolloutTreeNode | RolloutTreeBranchNode:
+        """
+        Groups time steps. Recursion is used to handle branches.
+        """
+        assert isinstance(current_node, RolloutTreeNode) or isinstance(
+            current_node, RolloutTreeBranchNode
+        ), "Current node must be a tree node or a branch node. Is of type: " + str(
+            type(current_node)
+        )
+        first_group_node = None
+        current_group_node = None
+        while current_node is not None:
+            if isinstance(current_node, RolloutTreeBranchNode):
+                raise Exception(
+                    "Grouping timesteps by round is not supported for branching trajectories yet."
+                )
+
+            # Accumulate
+            accumulation_step_logs.append(current_node.step_log)
+            if accumulation_stop_condition(current_node.step_log):
+                grouped_step_logs = group_step_logs(accumulation_step_logs)
+                accumulation_step_logs = []
+                new_group_node = RolloutTreeNode(
+                    step_log=grouped_step_logs, time_step=group_time_step, child=None
+                )
+                if first_group_node == None:
+                    first_group_node = new_group_node
+                group_time_step += 1
+                if current_group_node is not None:
+                    current_group_node.child = new_group_node
+                current_group_node = new_group_node
+            current_node = current_node.child
+        return first_group_node
+
+    node = group_time_steps_rec(
+        current_node=rollout_tree.child, group_time_step=0, accumulation_step_logs=[]
+    )
+    return RolloutTreeRootNode(
+        id=rollout_tree.id,
+        crn_id=rollout_tree.crn_id,
+        child=node,
+        agent_ids=rollout_tree.agent_ids,
+    )
+
+
+def stop_when_round_ends(step_log: StepLog) -> bool:
+    """
+    Simplest stop condition. Will return True if step log is the last time step of a round.
+    This will throw an error if this information is not available in the simulation info.
+    """
+    assert (
+        "is_last_timestep_in_round" in step_log.simulation_step_log.info.keys()
+    ), "To group by round, is_last_timestep_in_round must be set in the info of your simulation step log at each time step."
+    return step_log.simulation_step_log.info["is_last_timestep_in_round"]
+
+
+def group_by_round(rollout_tree: RolloutTreeRootNode) -> RolloutTreeRootNode:
+    """
+    Groups time steps by round.
+    """
+    return group_time_steps(rollout_tree, stop_when_round_ends)

src_code_for_reproducibility/markov_games/ipd/ipd_agent.py

@@ -0,0 +1,120 @@
+"""
+File: mllm/markov_games/ipd/ipd_agent.py
+Summary: Implements the IPD agent abstraction used during simulations.
+"""
+
+import copy
+import json
+import random
+import re
+from collections.abc import Callable
+from copy import deepcopy
+from dataclasses import dataclass, field
+from typing import Any, Dict, List, Optional, Tuple, Union
+
+from mllm.markov_games.agent import Agent
+from mllm.markov_games.rollout_tree import AgentActLog, ChatTurn
+
+
+@dataclass
+class IPDAgentState:
+    """
+    Tracks retry count, round index, and chat history for a single IPD agent.
+    """
+
+    nb_retries: int
+    round_nb: int
+    chat_counter: int
+    chat_history: List[ChatTurn]
+
+
+@dataclass
+class IPDAgent(Agent):
+    seed: int
+    agent_id: str
+    agent_name: str
+    policy: Callable[[List[Dict]], str]
+    intro_prompt: str  # Introduction prompt explaining the game rules
+    goal_prompt: str  # Prompt explaining the agent's goal
+    strategy_prompt: str  # Prompt suggesting a strategy to the agent
+    max_errors: int  # Maximum number of errors allowed before default action
+    allow_reasoning: bool  # Whether to allow reasoning in the response
+    max_reasoning_chars: int  # Maximum number of characters for reasoning
+    cooperate_string: str  # string parsed as playing cooperate by simulation
+    defect_string: str  # string parsed as playing defect by simulation
+
+    def __post_init__(self):
+        self.state = IPDAgentState(
+            nb_retries=0, round_nb=0, chat_counter=0, chat_history=[]
+        )
+
+    async def act(self, observation) -> Tuple[Any, AgentActLog]:
+        """
+        Run the LLM policy conversation until a valid cooperate/defect action is produced.
+        """
+
+        action = None
+        action_is_ready = False
+        round_nb = observation.round_nb
+
+        # If it's the first round, we need to send the intro prompt
+        if round_nb == 0 and self.state.chat_counter == 0:
+            self.state.chat_history.append(
+                ChatTurn(
+                    agent_id=self.agent_id,
+                    role="user",
+                    content=self.intro_prompt,
+                    is_state_end=True,
+                )
+            )
+
+        # If new round
+        if round_nb > self.state.round_nb:
+            coagent_action = observation.last_coagent_move
+            user_message = f"Last round, the other agent played {coagent_action}."
+            self.state.chat_history.append(
+                ChatTurn(
+                    agent_id=self.agent_id,
+                    role="user",
+                    content=user_message,
+                    is_state_end=True,
+                )
+            )
+
+        # If not new round, try to get valid action from policy
+        output_chat_turn: ChatTurn = await self.policy(
+            state=self.state.chat_history,
+            agent_id=self.agent_id,
+            regex=f"({self.cooperate_string}|{self.defect_string})",
+        )
+        self.state.chat_history.append(output_chat_turn)
+        action = output_chat_turn.content
+
+        agent_step_log = AgentActLog(
+            chat_turns=self.state.chat_history[self.state.chat_counter :], info=None
+        )
+        self.state.chat_counter = len(self.state.chat_history)
+        self.state.round_nb = round_nb
+
+        return action, agent_step_log
+
+    def get_safe_copy(self):
+        """
+        Return a safe copy of the agent.
+        """
+        agent_copy = copy.copy(self)
+        agent_copy.state = copy.deepcopy(self.state)
+        return agent_copy
+
+    def reset(self):
+        self.state = IPDAgentState()
+        raise NotImplementedError
+
+    def render(self):
+        pass
+
+    def close(self):
+        pass
+
+    def get_agent_info(self):
+        pass

src_code_for_reproducibility/markov_games/linear_runner.py

@@ -0,0 +1,42 @@
+"""
+File: mllm/markov_games/linear_runner.py
+Summary: Simulates a single unbranched Markov-game rollout and records it.
+"""
+
+import asyncio
+import json
+import os.path
+
+from mllm.markov_games.markov_game import MarkovGame
+from mllm.markov_games.rollout_tree import RolloutTreeNode, RolloutTreeRootNode
+
+
+async def LinearRunner(
+    markov_game: MarkovGame, output_folder: str
+) -> RolloutTreeRootNode:
+    """
+    Generate a single main-path rollout (no branching) for the provided Markov game.
+
+    Parameters
+    ----------
+    markov_game:
+        Initialized ``MarkovGame`` with agents + simulation ready to step.
+    output_folder:
+        Unused placeholder in the legacy API (kept for compatibility).
+    """
+    time_step = 0
+    terminated = False
+    root = RolloutTreeRootNode(
+        id=markov_game.get_id(),
+        crn_id=markov_game.get_crn_id(),
+        agent_ids=markov_game.get_agent_ids(),
+    )
+    previous_node = root
+    while not terminated:
+        terminated, step_log = await markov_game.step()
+        current_node = RolloutTreeNode(step_log=step_log, time_step=time_step)
+        previous_node.child = current_node
+        previous_node = current_node
+        time_step += 1
+
+    return root

src_code_for_reproducibility/markov_games/markov_game.py

@@ -0,0 +1,217 @@
+"""
+File: mllm/markov_games/markov_game.py
+Summary: Defines the MarkovGame base class plus shared simulation interfaces.
+"""
+
+import asyncio
+import copy
+import json
+import os
+from dataclasses import dataclass
+from typing import Any, List, Literal, Optional, Tuple
+
+from transformers.models.idefics2 import Idefics2Config
+
+from mllm.markov_games.agent import Agent
+from mllm.markov_games.rollout_tree import AgentActLog, StepLog
+from mllm.markov_games.simulation import Simulation
+
+AgentId = str
+
+
+@dataclass
+class AgentAndActionSafeCopy:
+    """Snapshot of an agent, its action, and metadata used for branch replay."""
+
+    action: Any
+    action_info: AgentActLog
+    agent_after_action: type[Agent]
+
+
+class MarkovGame(object):
+    def __init__(
+        self,
+        id: int,
+        agents: dict[AgentId, type[Agent]],
+        simulation: type[Simulation],
+        crn_id: int,
+    ):
+        """
+        Initialize the Markov game wrapper.
+
+        Parameters
+        ----------
+        id:
+            Unique rollout identifier (logged into rollout trees).
+        agents:
+            Mapping of agent_id -> Agent instance.
+        simulation:
+            Environment implementing the ``Simulation`` interface (IPD, TAS, etc.).
+        crn_id:
+            Identifier for the common random number stream used by this rollout.
+        """
+        self.agents = agents
+        self.agent_ids = self.agents.keys()
+        self.simulation = simulation
+        self.simulation_step_log = None
+        self.agent_step_logs = {agent_id: None for agent_id in self.agent_ids}
+        self.actions = {}
+        self.id = id
+        self.crn_id = crn_id
+
+    def get_id(self) -> str:
+        return self.id
+
+    def get_crn_id(self) -> int:
+        return self.crn_id
+
+    def get_agent_ids(self) -> List[AgentId]:
+        return list(self.agent_ids)
+
+    async def get_action_of_agent_without_side_effects(
+        self, agent_id: AgentId
+    ) -> Tuple[Any, AgentActLog]:
+        """
+        Safe function to get an action of an agent without modifying the agent or the simulation.
+        """
+        agent = self.agents[agent_id]
+        agent_before_action = agent.get_safe_copy()
+        obs = self.simulation.get_obs_agent(agent_id)
+        action, action_info = await agent.act(observation=obs)
+        self.agents[agent_id] = agent_before_action
+        agent_after_action = agent.get_safe_copy()
+        return AgentAndActionSafeCopy(action, action_info, agent_after_action)
+
+    async def get_actions_of_agents_without_side_effects(
+        self,
+    ) -> dict[AgentId, AgentAndActionSafeCopy]:
+        """
+        Safe function to get an action of an agent without modifying the agent or the simulation.
+        """
+        tasks = []
+        for agent_id in self.agent_ids:
+            task = asyncio.create_task(
+                self.get_action_of_agent_without_side_effects(agent_id)
+            )
+            tasks.append(task)
+        agent_and_action_safe_copies: list[
+            AgentAndActionSafeCopy
+        ] = await asyncio.gather(*tasks)
+        return {
+            agent_id: agent_and_action_safe_copy
+            for agent_id, agent_and_action_safe_copy in zip(
+                self.agent_ids, agent_and_action_safe_copies
+            )
+        }
+
+    def set_action_and_agent_after_action_manually(
+        self,
+        agent_id: AgentId,
+        agent_action_safe_copy: AgentAndActionSafeCopy,
+    ):
+        """
+        Set the action and the agent after action manually.
+        """
+        self.actions[agent_id] = agent_action_safe_copy.action
+        self.agent_step_logs[agent_id] = agent_action_safe_copy.action_info
+        self.agents[agent_id] = agent_action_safe_copy.agent_after_action
+
+    def set_actions_of_agents_manually(
+        self, actions: dict[AgentId, AgentAndActionSafeCopy]
+    ):
+        """
+        Set the actions of agents manually.
+        """
+        for agent_id, agent_action_safe_copy in actions.items():
+            self.set_action_and_agent_after_action_manually(
+                agent_id, agent_action_safe_copy
+            )
+
+    async def set_action_of_agent(self, agent_id: AgentId):
+        """
+        Query a single agent for its next action and store the result locally.
+        """
+        agent = self.agents[agent_id]
+        obs = self.simulation.get_obs_agent(agent_id)
+        action, action_info = await agent.act(observation=obs)
+        self.actions[agent_id] = action
+        self.agent_step_logs[agent_id] = action_info
+
+    async def set_actions(self):
+        """
+        Query every agent concurrently and populate the cached actions/logs.
+        """
+        # background_tasks = set()
+        tasks = []
+        for agent_id in self.agent_ids:
+            task = asyncio.create_task(self.set_action_of_agent(agent_id))
+            tasks.append(task)
+        await asyncio.gather(*tasks)
+
+    def take_simulation_step(self):
+        """
+        Advance the simulation by one step using the cached actions.
+        """
+        terminated, self.simulation_step_log = self.simulation.step(self.actions)
+        return terminated
+
+    def get_step_log(self) -> StepLog:
+        """
+        Package the most recent simulation step and agent logs into a StepLog.
+        """
+        if self.simulation_step_log is None:
+            raise RuntimeError(
+                "Simulation step log is empty; call take_simulation_step() first."
+            )
+        missing_logs = [
+            agent_id for agent_id, log in self.agent_step_logs.items() if log is None
+        ]
+        if missing_logs:
+            raise RuntimeError(
+                f"Agent action logs missing for: {', '.join(missing_logs)}. "
+                "Ensure set_actions() ran before requesting the step log."
+            )
+        step_log = StepLog(
+            simulation_step_log=self.simulation_step_log,
+            action_logs=self.agent_step_logs,
+        )
+        return step_log
+
+    async def step(self) -> Tuple[bool, StepLog]:
+        """
+        Convenience step that collects actions, advances the simulation, and returns the log.
+        """
+        await self.set_actions()
+        terminated = self.take_simulation_step()
+        step_log = self.get_step_log()
+        return terminated, step_log
+
+    def get_safe_copy(self):
+        """
+        Create a shallow copy of the game with deep-copied agents/simulation for branching.
+        """
+
+        new_markov_game = copy.copy(self)
+        new_simulation = self.simulation.get_safe_copy()
+        new_agents = {
+            agent_id: agent.get_safe_copy() for agent_id, agent in self.agents.items()
+        }
+
+        # Reassign copied components
+        new_markov_game.simulation = new_simulation
+        new_markov_game.agents = new_agents
+
+        # IMPORTANT: ensure agent_ids references the new agents dict, not the original
+        new_markov_game.agent_ids = new_markov_game.agents.keys()
+
+        # Deep-copy step data to avoid correlation
+        new_markov_game.simulation_step_log = copy.deepcopy(self.simulation_step_log)
+        new_markov_game.actions = copy.deepcopy(self.actions)
+        # Rebuild logs to align exactly with new agent ids
+        old_agent_step_logs = copy.deepcopy(self.agent_step_logs)
+        new_markov_game.agent_step_logs = {
+            agent_id: old_agent_step_logs.get(agent_id)
+            for agent_id in new_markov_game.agent_ids
+        }
+
+        return new_markov_game

src_code_for_reproducibility/markov_games/mg_utils.py

@@ -0,0 +1,97 @@
+"""
+File: mllm/markov_games/mg_utils.py
+Summary: Holds miscellaneous helpers shared across Markov-game modules.
+"""
+
+import asyncio
+import copy
+from collections.abc import Callable
+from dataclasses import dataclass
+
+from mllm.markov_games.ipd.ipd_agent import IPDAgent
+from mllm.markov_games.ipd.Ipd_hard_coded_agents import (
+    AlwaysCooperateIPDAgent,
+    AlwaysDefectIPDAgent,
+)
+from mllm.markov_games.ipd.ipd_simulation import IPD
+from mllm.markov_games.markov_game import MarkovGame
+from mllm.markov_games.negotiation.dond_agent import DealNoDealAgent
+from mllm.markov_games.negotiation.dond_simulation import DealNoDealSimulation
+from mllm.markov_games.negotiation.nego_hard_coded_policies import (
+    HardCodedNegoGreedyPolicy,
+    HardCodedNegoWelfareMaximizingPolicy,
+)
+from mllm.markov_games.negotiation.no_press_nego_agent import NoPressAgent
+from mllm.markov_games.negotiation.no_press_nego_simulation import NoPressSimulation
+from mllm.markov_games.negotiation.tas_rps_agent import TrustAndSplitRPSAgent
+from mllm.markov_games.negotiation.tas_rps_simulation import TrustAndSplitRPSSimulation
+from mllm.markov_games.rollout_tree import (
+    AgentActLog,
+    RolloutTreeBranchNode,
+    RolloutTreeNode,
+    RolloutTreeRootNode,
+    StepLog,
+)
+from mllm.markov_games.simulation import SimulationStepLog
+
+AgentId = str
+
+
+@dataclass
+class AgentConfig:
+    """Configuration blob describing one agent in a Markov game spec."""
+
+    agent_id: str
+    agent_name: str
+    agent_class_name: str
+    policy_id: str
+    init_kwargs: dict
+
+
+@dataclass
+class MarkovGameConfig:
+    """Top-level config that ties together simulation settings and agent configs."""
+
+    id: int
+    seed: int
+    simulation_class_name: str
+    simulation_init_args: dict
+    agent_configs: list[AgentConfig]
+
+
+def init_markov_game_components(
+    config: MarkovGameConfig, policies: dict[str, Callable[[list[dict]], str]]
+):
+    """
+    Materialize Agents and the Simulation described by ``config`` and return a MarkovGame.
+
+    `policies` is a mapping of policy_id -> callable retrieved from the hosting trainer.
+    """
+    agents = {}
+    agent_names = []
+    for agent_config in config.agent_configs:
+        agent_id = agent_config.agent_id
+        agent_name = agent_config.agent_name
+        agent_class = eval(agent_config.agent_class_name)
+        agent = agent_class(
+            seed=config.seed,
+            agent_id=agent_id,
+            agent_name=agent_name,
+            policy=policies[agent_config.policy_id],
+            **agent_config.init_kwargs,
+        )
+        agents[agent_id] = agent
+        agent_names.append(agent_name)
+    simulation = eval(config.simulation_class_name)(
+        seed=config.seed,
+        agent_ids=list(agents.keys()),
+        agent_names=agent_names,
+        **config.simulation_init_args,
+    )
+    markov_game = MarkovGame(
+        id=config.id,
+        crn_id=config.seed,
+        agents=agents,
+        simulation=simulation,
+    )
+    return markov_game

src_code_for_reproducibility/markov_games/negotiation/nego_simulation.py

@@ -0,0 +1,252 @@
+"""
+File: mllm/markov_games/negotiation/nego_simulation.py
+Summary: Simulation harness for general negotiation environments.
+"""
+
+import copy
+from abc import abstractmethod
+from dataclasses import dataclass
+from typing import Any, Dict, List, Tuple
+
+from numpy.random import default_rng
+
+from mllm.markov_games.rollout_tree import SimulationStepLog
+from mllm.markov_games.simulation import Simulation
+from mllm.utils.get_coagent_id import get_coagent_id
+
+AgentId = str
+
+
+@dataclass
+class Split:
+    """Structured proposal describing how many units of each item an agent keeps."""
+
+    items_given_to_self: Dict[str, int]
+
+
+@dataclass
+class Message:
+    """Single chat utterance exchanged during the negotiation phase."""
+
+    message: str
+
+
+@dataclass  # gets extended by variants
+class NegotiationState:
+    """Full simulator state snapshot shared by all negotiation variants."""
+
+    round_nb: int
+    last_message: str
+    current_agent: AgentId
+    quantities: Dict[str, int]
+    values: Dict[AgentId, Dict[str, float]]
+    splits: Dict[AgentId, Split | None]
+    nb_messages_sent: Dict[AgentId, int]
+    previous_values: Dict[AgentId, Dict[str, float]] | None
+    previous_splits: Dict[AgentId, Dict[str, int] | None] | None
+    previous_points: Dict[AgentId, float] | None
+    previous_quantities: Dict[str, int] | None
+    split_phase: bool
+
+
+@dataclass  # gets extended by variants
+class NegotiationObs:
+    """Observation presented to agents each turn (base fields; variants extend)."""
+
+    round_nb: int
+    last_message: str
+    quota_messages_per_agent_per_round: int
+    current_agent: AgentId
+    other_agent: str
+    quantities: Dict[str, int]
+    item_types: List[str]
+    value: Dict[str, int]
+    split_phase: bool
+    last_split_agent: Dict[str, int] | None
+    last_value_agent: Dict[str, int] | None
+    last_points_agent: float | None
+    last_split_coagent: Dict[str, int] | None
+    last_value_coagent: Dict[str, int] | None
+    last_points_coagent: float | None
+    last_quantities: Dict[str, int] | None
+
+
+def compute_tas_style_rewards(
+    agent_ids: List[AgentId],
+    values: Dict[AgentId, float],
+    splits: Dict[AgentId, Split],
+    quantities: Dict[str, int],
+) -> Dict[AgentId, float]:
+    """
+    TAS-like reward computation: if sum of proposed coins exceeds max_coins,
+    allocate proportionally. Otherwise, use proposed amounts directly.
+    Rewards are quantity_kept * per-coin value for each agent.
+    """
+    a0, a1 = agent_ids[0], agent_ids[1]
+    r0, r1 = 0.0, 0.0
+
+    for item in quantities:
+        max_item = quantities[item]
+        item_to_self_0 = int(
+            (splits[a0].items_given_to_self.get(item, 0))
+            if splits[a0] is not None
+            else 0
+        )
+        item_to_self_1 = int(
+            (splits[a1].items_given_to_self.get(item, 0))
+            if splits[a1] is not None
+            else 0
+        )
+        denom = max(int(max_item), item_to_self_0 + item_to_self_1)
+        q0 = float(max_item) * float(item_to_self_0) / float(denom)
+        q1 = float(max_item) * float(item_to_self_1) / float(denom)
+        if type(values[a0]) is not dict:
+            r0 += q0 * float(values[a0])
+            r1 += q1 * float(values[a1])
+        else:
+            r0 += q0 * float(values[a0][item])
+            r1 += q1 * float(values[a1][item])
+    return {a0: r0, a1: r1}
+
+
+class NegotiationSimulation(Simulation):
+    def __init__(
+        self,
+        agent_ids: List[AgentId],
+        agent_names: List[str],
+        seed: int,
+        nb_of_rounds: int,
+        quota_messages_per_agent_per_round: int,
+        item_types: List[str] | None = None,
+    ):
+        self.seed = seed
+        self.rng = default_rng(self.seed)
+        self.agent_ids = list(agent_ids)
+        self.agent_names = agent_names
+        self.agent_id_to_name = {
+            agent_id: agent_name for agent_id, agent_name in zip(agent_ids, agent_names)
+        }
+        self.nb_of_rounds = int(nb_of_rounds)
+        self.quota_messages_per_agent_per_round = int(
+            quota_messages_per_agent_per_round
+        )
+        if item_types is not None:
+            self.item_types = [item.lower() for item in item_types]
+        else:
+            self.item_types = ["coins"]
+        self.state: NegotiationState | None = None
+        self._starting_agent_index = self.rng.choice([0, 1])
+        self.reset()
+
+    def _other(self, agent_id: AgentId) -> AgentId:
+        return get_coagent_id(self.agent_ids, agent_id)
+
+    @abstractmethod
+    def set_new_round_of_variant(self):
+        """Variant hook: sample new private values / stock before each round."""
+        pass
+
+    @abstractmethod
+    def get_info_of_variant(
+        self, state: NegotiationState, actions: Dict[AgentId, Any]
+    ) -> Dict[str, Any]:
+        """Variant hook: populate SimulationStepLog.info with custom diagnostics."""
+        pass
+
+    def step(self, actions: Any) -> Tuple[bool, SimulationStepLog]:
+        """
+        Returns terminated, step_log
+        """
+        assert self.state is not None
+        current_agent = self.state.current_agent
+        a0, a1 = self.agent_ids[0], self.agent_ids[1]
+        action = actions.get(current_agent)
+
+        # Split phase: require both splits in the same timestep
+        if self.state.split_phase:
+            action_a0 = actions.get(a0)
+            action_a1 = actions.get(a1)
+            have_both_splits = isinstance(action_a0, Split) and isinstance(
+                action_a1, Split
+            )
+            if not have_both_splits:
+                rewards = {agent_id: 0.0 for agent_id in self.agent_ids}
+                return False, SimulationStepLog(
+                    rewards=rewards, info={"type": "waiting_for_splits"}
+                )
+
+            # Record splits
+            self.state.splits[a0] = action_a0
+            self.state.splits[a1] = action_a1
+
+            # Compute rewards and end round
+            rewards = self.get_rewards(self.state.splits)
+
+            # Info
+            info = self.get_info_of_variant(self.state, actions)
+
+            # Prepare next round
+            # Alternate starting agent
+            self.state.round_nb += 1
+            self._starting_agent_index = 1 - self._starting_agent_index
+            self.state.current_agent = self.agent_ids[self._starting_agent_index]
+            self.state.previous_values = copy.deepcopy(self.state.values)
+            self.state.previous_splits = copy.deepcopy(self.state.splits)
+            self.state.previous_quantities = copy.deepcopy(self.state.quantities)
+            self.state.previous_points = copy.deepcopy(rewards)
+            self.state.last_message = ""
+            self.set_new_round_of_variant()  # variant specific
+            self.state.splits = {agent_id: None for agent_id in self.agent_ids}
+            self.state.nb_messages_sent = {agent_id: 0 for agent_id in self.agent_ids}
+            is_last_timestep_in_round = True
+            done = self.state.round_nb >= self.nb_of_rounds
+
+        # Message phase: roll the conversation forward a single turn.
+        elif isinstance(action, Message):
+            self.state.last_message = action.message
+            self.state.nb_messages_sent[current_agent] += 1
+
+            # Move turn to other agent
+            self.state.current_agent = self._other(current_agent)
+
+            # If both agents have reached their message quota, enter split phase
+            if all(
+                self.state.nb_messages_sent[agent_id]
+                >= self.quota_messages_per_agent_per_round
+                for agent_id in self.agent_ids
+            ):
+                self.state.split_phase = True
+            is_last_timestep_in_round = False
+            done = False
+            rewards = {agent_id: 0.0 for agent_id in self.agent_ids}
+            info = {"type": "message"}
+
+        info[
+            "is_last_timestep_in_round"
+        ] = is_last_timestep_in_round  # Used later to group round timesteps if needed
+        return done, SimulationStepLog(rewards=rewards, info=info)
+
+    def get_obs(self):
+        """Returns all agent observations in dict"""
+        return {agent_id: self.get_obs_agent(agent_id) for agent_id in self.agent_ids}
+
+    @abstractmethod
+    def get_rewards(self, splits: Dict[AgentId, Split]) -> Dict[AgentId, float]:
+        pass
+
+    @abstractmethod
+    def get_obs_agent(self, agent_id):
+        pass
+
+    def get_state(self):
+        return self.state
+
+    def get_safe_copy(self):
+        """Return a safe copy of the simulation."""
+        simulation_copy = copy.copy(self)
+        simulation_copy.state = copy.deepcopy(self.state)
+        return simulation_copy
+
+    @abstractmethod
+    def reset(self) -> dict[AgentId, NegotiationObs]:
+        pass

src_code_for_reproducibility/markov_games/rollout_tree.py

@@ -0,0 +1,95 @@
+"""
+File: mllm/markov_games/rollout_tree.py
+Summary: Defines rollout tree data structures and serialization helpers.
+"""
+
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any, List, Literal, Optional, Tuple
+
+import jsonschema
+from pydantic import BaseModel, Field, model_validator
+
+from mllm.chat_utils.chat_turn import ChatTurn
+
+AgentId = str
+
+
+class SimulationStepLog(BaseModel):
+    """Minimal snapshot of environment-side rewards and auxiliary info."""
+
+    rewards: dict[AgentId, float]
+    info: Any = None
+
+
+class AgentActLog(BaseModel):
+    """LLM-side provenance for an action (chat turns + metadata)."""
+
+    chat_turns: list[ChatTurn] | None
+    info: Any = None
+
+    @model_validator(mode="after")
+    def _exactly_one_state_end(self):
+        """
+        This method is used to enforce that for each AgentActLog, there is exactly one ChatTurn which is a state end.
+        """
+        if self.chat_turns != []:
+            n = sum(1 for t in self.chat_turns if t.is_state_end)
+            if n != 1:
+                raise ValueError(
+                    f"AgentActLog must have exactly one ChatTurn with is_state_end=True; got {self.chat_turns}."
+                )
+            return self
+        else:
+            return self
+
+
+class StepLog(BaseModel):
+    action_logs: dict[AgentId, AgentActLog]
+    simulation_step_log: SimulationStepLog
+
+
+# BranchType = Literal["unilateral_deviation", "common_deviation"] # might not be necessary
+# class BranchNodeInfo(BaseModel):
+#     branch_id: str
+#     branch_for: AgentId
+#     branch_type: BranchType
+
+
+class RolloutTreeNode(BaseModel):
+    """Single timestep of the main trajectory (or a branch) plus linkage."""
+
+    step_log: StepLog
+    time_step: int
+    child: RolloutTreeNode | RolloutTreeBranchNode | None = None
+
+
+class RolloutTreeBranchNode(BaseModel):
+    """
+    First item of the tuple indicates which agent "called" for an alternative branch.
+    """
+
+    main_child: RolloutTreeNode
+    branches: dict[AgentId, list[RolloutTreeNode]] | None = None
+
+
+class RolloutTreeRootNode(BaseModel):
+    """Entry point for serialized rollouts (main path plus optional branches)."""
+
+    id: int
+    crn_id: int  # ID of the rng used to generate this rollout tree
+    child: RolloutTreeNode | RolloutTreeBranchNode | None = None
+    agent_ids: List[AgentId] = Field(min_length=1)
+
+
+# class RolloutTreeLeafNode(BaseModel):
+#     step_log: StepLog
+#     time_step: int
+
+
+# Necessary for self-referential stuff in pydantic
+RolloutTreeBranchNode.model_rebuild()
+RolloutTreeNode.model_rebuild()

src_code_for_reproducibility/markov_games/run_markov_games.py

@@ -0,0 +1,35 @@
+"""
+File: mllm/markov_games/run_markov_games.py
+Summary: CLI entry point for running configured Markov-game experiments.
+"""
+
+import asyncio
+from collections.abc import Callable
+from dataclasses import dataclass
+
+from torch._C import ClassType
+
+from mllm.markov_games.markov_game import MarkovGame
+from mllm.markov_games.rollout_tree import RolloutTreeRootNode
+
+
+async def run_markov_games(
+    runner: Callable[[MarkovGame], RolloutTreeRootNode],
+    runner_kwargs: dict,
+    output_folder: str,
+    markov_games: list[MarkovGame],
+) -> list[RolloutTreeRootNode]:
+    """
+    Kick off multiple Markov game rollouts concurrently and return their trees.
+
+    Parameters mirror the Hydra configs (runner callable + kwargs) so callers can
+    choose ``LinearRunner``, ``AlternativeActionsRunner`` or future variants.
+    """
+    tasks = []
+    for mg in markov_games:
+        tasks.append(
+            asyncio.create_task(
+                runner(markov_game=mg, output_folder=output_folder, **runner_kwargs)
+            )
+        )
+    return await asyncio.gather(*tasks)

src_code_for_reproducibility/markov_games/simulation.py

@@ -0,0 +1,94 @@
+"""
+File: mllm/markov_games/simulation.py
+Summary: Core simulation loop utilities and step logging for Markov games.
+"""
+
+from abc import ABC, abstractmethod
+from typing import Any, Tuple
+
+from numpy.random import default_rng
+
+from mllm.markov_games.rollout_tree import SimulationStepLog
+
+
+class Simulation(ABC):
+    @abstractmethod
+    def __init__(self, seed: int, *args, **kwargs):
+        self.seed = seed
+        self.rng = default_rng(self.seed)
+
+    @abstractmethod
+    def step(self, actions: Any) -> Tuple[bool, SimulationStepLog]:
+        """
+        Advance the environment by one logical tick using ``actions``.
+
+        Returns
+        -------
+        terminated: bool
+            Whether the episode has finished.
+        SimulationStepLog
+            Reward/info bundle describing this transition.
+        """
+        raise NotImplementedError
+
+    def get_obs(self):
+        """Return a dict mapping agent_id -> observation for *all* agents."""
+        raise NotImplementedError
+
+    def get_obs_agent(self, agent_id):
+        """Return the observation for a single agent."""
+        raise NotImplementedError
+
+    def get_obs_size(self):
+        """Describe the observation tensor shape (useful for critic heads)."""
+        raise NotImplementedError
+
+    def get_state(self):
+        """Return the privileged simulator state if available."""
+        raise NotImplementedError
+
+    def get_state_size(self):
+        """Describe the state tensor shape."""
+        raise NotImplementedError
+
+    def get_avail_actions(self):
+        """Return the global action mask/tensor if the space is discrete."""
+        raise NotImplementedError
+
+    def get_avail_agent_actions(self, agent_id):
+        """Return the available action mask for a given agent."""
+        raise NotImplementedError
+
+    def get_total_actions(self):
+        """Returns the total number of actions an agent could ever take.
+
+        Implementations currently assume a discrete, one-dimensional action space per agent.
+        """
+        raise NotImplementedError
+
+    def get_safe_copy(self):
+        """
+        Return copy of the simulator that shares no mutable state with the original.
+        """
+        raise NotImplementedError
+
+    def reset(self):
+        """Reset to the initial state and return the starting observations."""
+        raise NotImplementedError
+
+    def render(self):
+        """Optional human-facing visualization."""
+        raise NotImplementedError
+
+    def close(self):
+        """Release any owned resources (files, processes, etc.)."""
+        raise NotImplementedError
+
+    # def seed(self):
+    #     raise NotImplementedError
+
+    def save_replay(self):
+        raise NotImplementedError
+
+    def get_simulation_info(self):
+        raise NotImplementedError

src_code_for_reproducibility/markov_games/statistics_runner.py

@@ -0,0 +1,415 @@
+"""
+File: mllm/markov_games/statistics_runner.py
+Summary: Executes multiple rollouts to compute experiment statistics.
+"""
+
+from __future__ import annotations
+
+import gc
+import json
+import pickle
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any, Callable, Dict, Iterable, Iterator, List, Optional
+
+from basic_render import find_iteration_folders
+
+from mllm.markov_games.rollout_tree import (
+    RolloutTreeBranchNode,
+    RolloutTreeNode,
+    RolloutTreeRootNode,
+    SimulationStepLog,
+)
+
+
+def _iterate_main_nodes(root: RolloutTreeRootNode) -> Iterator[RolloutTreeNode]:
+    """
+    Iterate the main path nodes without materializing full path lists.
+    """
+    current = root.child
+    while current is not None:
+        if isinstance(current, RolloutTreeNode):
+            yield current
+            current = current.child
+        elif isinstance(current, RolloutTreeBranchNode):
+            # Follow only the main child on the main trajectory
+            current = current.main_child
+        else:
+            break
+
+
+def iterate_main_simulation_logs(
+    root: RolloutTreeRootNode,
+) -> Iterator[SimulationStepLog]:
+    """Yield ``SimulationStepLog`` objects along the main (non-branch) path."""
+    for node in _iterate_main_nodes(root):
+        yield node.step_log.simulation_step_log
+
+
+def stream_rollout_files(iteration_folder: Path) -> Iterator[Path]:
+    """Iterate over every ``*.rt.pkl`` file under an iteration directory."""
+    for p in iteration_folder.rglob("*.rt.pkl"):
+        if p.is_file():
+            yield p
+
+
+def load_root(path: Path) -> RolloutTreeRootNode:
+    """Load and validate a rollout tree from disk."""
+    with open(path, "rb") as f:
+        data = pickle.load(f)
+    return RolloutTreeRootNode.model_validate(data)
+
+
+@dataclass
+class StatRecord:
+    """Convenience container for serialized stat rows."""
+
+    mgid: int
+    crn_id: Optional[int]
+    iteration: str
+    values: Dict[str, Any]
+
+
+class StatComputer:
+    """
+    Stateful stat computer that consumes SimulationStepLog instances
+    and produces final aggregated values for one rollout (mgid).
+    """
+
+    def update(self, sl: SimulationStepLog) -> None:  # pragma: no cover - interface
+        raise NotImplementedError
+
+    def finalize(self) -> Dict[str, Any]:  # pragma: no cover - interface
+        raise NotImplementedError
+
+
+def run_stats(
+    data_root: Path,
+    game_name: str,
+    make_computers: Callable[[], List[StatComputer]],
+    output_filename: Optional[str] = None,
+    output_format: str = "json",  # "json" (dict of lists) or "jsonl"
+) -> Path:
+    """
+    Compute stats across all iteration_* folders under data_root.
+    Writes JSONL to data_root/statistics/<output_filename or f"{game_name}.stats.jsonl">.
+    """
+    data_root = Path(data_root)
+    outdir = data_root / "statistics"
+    outdir.mkdir(parents=True, exist_ok=True)
+    # Choose extension by format
+    default_name = (
+        f"{game_name}.stats.json"
+        if output_format == "json"
+        else f"{game_name}.stats.jsonl"
+    )
+    outfile = outdir / (
+        output_filename if output_filename is not None else default_name
+    )
+
+    # Rewrite file each run to keep it clean and small
+    if outfile.exists():
+        outfile.unlink()
+
+    iteration_folders = find_iteration_folders(str(data_root))
+
+    # If writing JSONL, stream directly; otherwise accumulate minimal records
+    if output_format == "jsonl":
+        with open(outfile, "w", encoding="utf-8") as w:
+            for iteration_folder in iteration_folders:
+                iteration_name = Path(iteration_folder).name
+                for pkl_path in stream_rollout_files(Path(iteration_folder)):
+                    root = load_root(pkl_path)
+
+                    computers = make_computers()
+                    for sl in iterate_main_simulation_logs(root):
+                        for comp in computers:
+                            try:
+                                comp.update(sl)
+                            except Exception:
+                                continue
+
+                    values: Dict[str, Any] = {}
+                    for comp in computers:
+                        try:
+                            values.update(comp.finalize())
+                        except Exception:
+                            continue
+
+                    rec = {
+                        "mgid": getattr(root, "id", None),
+                        "crn_id": getattr(root, "crn_id", None),
+                        "iteration": iteration_name,
+                        "stats": values,
+                    }
+                    w.write(json.dumps(rec, ensure_ascii=False) + "\n")
+
+                    del root
+                    del computers
+                    gc.collect()
+    else:
+        # Aggregate to dict-of-lists for easier plotting
+        records: List[Dict[str, Any]] = []
+        # Process in deterministic order
+        for iteration_folder in iteration_folders:
+            iteration_name = Path(iteration_folder).name
+            for pkl_path in stream_rollout_files(Path(iteration_folder)):
+                root = load_root(pkl_path)
+
+                computers = make_computers()
+                for sl in iterate_main_simulation_logs(root):
+                    for comp in computers:
+                        try:
+                            comp.update(sl)
+                        except Exception:
+                            continue
+
+                values: Dict[str, Any] = {}
+                for comp in computers:
+                    try:
+                        values.update(comp.finalize())
+                    except Exception:
+                        continue
+
+                records.append(
+                    {
+                        "mgid": getattr(root, "id", None),
+                        "crn_id": getattr(root, "crn_id", None),
+                        "iteration": iteration_name,
+                        "stats": values,
+                    }
+                )
+
+                del root
+                del computers
+                gc.collect()
+
+        # Build dict-of-lists with nested stats preserved
+        # Collect all stat keys and nested agent keys where needed
+        mgids: List[Any] = []
+        crn_ids: List[Any] = []
+        iterations_out: List[str] = []
+        # stats_out is a nested structure mirroring keys but with lists
+        stats_out: Dict[str, Any] = {}
+
+        # First pass to collect union of keys
+        stat_keys: set[str] = set()
+        nested_agent_keys: Dict[str, set[str]] = {}
+        for r in records:
+            stats = r.get("stats", {}) or {}
+            for k, v in stats.items():
+                stat_keys.add(k)
+                if isinstance(v, dict):
+                    nested = nested_agent_keys.setdefault(k, set())
+                    for ak in v.keys():
+                        nested.add(str(ak))
+
+        # Initialize structure
+        for k in stat_keys:
+            if k in nested_agent_keys:
+                stats_out[k] = {ak: [] for ak in sorted(nested_agent_keys[k])}
+            else:
+                stats_out[k] = []
+
+        # Fill lists
+        for r in records:
+            mgids.append(r.get("mgid"))
+            crn_ids.append(r.get("crn_id"))
+            iterations_out.append(r.get("iteration"))
+            stats = r.get("stats", {}) or {}
+            for k in stat_keys:
+                val = stats.get(k)
+                if isinstance(stats_out[k], dict):
+                    # per-agent dict
+                    agent_dict = val if isinstance(val, dict) else {}
+                    for ak in stats_out[k].keys():
+                        stats_out[k][ak].append(agent_dict.get(ak))
+                else:
+                    stats_out[k].append(val)
+
+        with open(outfile, "w", encoding="utf-8") as w:
+            json.dump(
+                {
+                    "mgid": mgids,
+                    "crn_id": crn_ids,
+                    "iteration": iterations_out,
+                    "stats": stats_out,
+                },
+                w,
+                ensure_ascii=False,
+            )
+
+    return outfile
+
+
+def run_stats_functional(
+    data_root: Path,
+    game_name: str,
+    metrics: Dict[str, Callable[[SimulationStepLog], Optional[Dict[str, float]]]],
+    output_filename: Optional[str] = None,
+    output_format: str = "json",
+) -> Path:
+    """
+    Functional variant where metrics is a dict of name -> f(SimulationStepLog) -> {agent_id: value}.
+    Aggregates per rollout by averaging over steps where a metric produced a value.
+    Writes a single consolidated file in data_root/statistics/.
+    """
+    data_root = Path(data_root)
+    outdir = data_root / "statistics"
+    outdir.mkdir(parents=True, exist_ok=True)
+    default_name = (
+        f"{game_name}.stats.json"
+        if output_format == "json"
+        else f"{game_name}.stats.jsonl"
+    )
+    outfile = outdir / (
+        output_filename if output_filename is not None else default_name
+    )
+
+    if outfile.exists():
+        outfile.unlink()
+
+    iteration_folders = find_iteration_folders(str(data_root))
+
+    def finalize_rollout(
+        agg: Dict[str, Dict[str, List[float]]]
+    ) -> Dict[str, Dict[str, float]]:
+        # avg per metric per agent
+        result: Dict[str, Dict[str, float]] = {}
+        for mname, agent_values in agg.items():
+            result[mname] = {}
+            for aid, vals in agent_values.items():
+                if not vals:
+                    result[mname][aid] = None  # keep alignment; could be None
+                else:
+                    result[mname][aid] = sum(vals) / len(vals)
+        return result
+
+    if output_format == "jsonl":
+        with open(outfile, "w", encoding="utf-8") as w:
+            for iteration_folder in iteration_folders:
+                iteration_name = Path(iteration_folder).name
+                for pkl_path in stream_rollout_files(Path(iteration_folder)):
+                    root = load_root(pkl_path)
+
+                    # aggregator structure: metric -> agent_id -> list of values
+                    agg: Dict[str, Dict[str, List[float]]] = {
+                        m: {} for m in metrics.keys()
+                    }
+
+                    for sl in iterate_main_simulation_logs(root):
+                        for mname, fn in metrics.items():
+                            try:
+                                vals = fn(sl)
+                            except Exception:
+                                vals = None
+                            if not vals:
+                                continue
+                            for aid, v in vals.items():
+                                if v is None:
+                                    continue
+                                lst = agg[mname].setdefault(str(aid), [])
+                                try:
+                                    lst.append(float(v))
+                                except Exception:
+                                    continue
+
+                    values = finalize_rollout(agg)
+                    rec = {
+                        "mgid": getattr(root, "id", None),
+                        "crn_id": getattr(root, "crn_id", None),
+                        "iteration": iteration_name,
+                        "stats": values,
+                    }
+                    w.write(json.dumps(rec, ensure_ascii=False) + "\n")
+
+                    del root
+                    gc.collect()
+    else:
+        records: List[Dict[str, Any]] = []
+        for iteration_folder in iteration_folders:
+            iteration_name = Path(iteration_folder).name
+            for pkl_path in stream_rollout_files(Path(iteration_folder)):
+                root = load_root(pkl_path)
+
+                agg: Dict[str, Dict[str, List[float]]] = {m: {} for m in metrics.keys()}
+                for sl in iterate_main_simulation_logs(root):
+                    for mname, fn in metrics.items():
+                        try:
+                            vals = fn(sl)
+                        except Exception:
+                            vals = None
+                        if not vals:
+                            continue
+                        for aid, v in vals.items():
+                            if v is None:
+                                continue
+                            lst = agg[mname].setdefault(str(aid), [])
+                            try:
+                                lst.append(float(v))
+                            except Exception:
+                                continue
+
+                values = finalize_rollout(agg)
+                records.append(
+                    {
+                        "mgid": getattr(root, "id", None),
+                        "crn_id": getattr(root, "crn_id", None),
+                        "iteration": iteration_name,
+                        "stats": values,
+                    }
+                )
+
+                del root
+                gc.collect()
+
+        # Build dict-of-lists output
+        mgids: List[Any] = []
+        crn_ids: List[Any] = []
+        iterations_out: List[str] = []
+        stats_out: Dict[str, Any] = {}
+
+        stat_keys: set[str] = set()
+        nested_agent_keys: Dict[str, set[str]] = {}
+        for r in records:
+            stats = r.get("stats", {}) or {}
+            for k, v in stats.items():
+                stat_keys.add(k)
+                if isinstance(v, dict):
+                    nested = nested_agent_keys.setdefault(k, set())
+                    for ak in v.keys():
+                        nested.add(str(ak))
+
+        for k in stat_keys:
+            if k in nested_agent_keys:
+                stats_out[k] = {ak: [] for ak in sorted(nested_agent_keys[k])}
+            else:
+                stats_out[k] = []
+
+        for r in records:
+            mgids.append(r.get("mgid"))
+            crn_ids.append(r.get("crn_id"))
+            iterations_out.append(r.get("iteration"))
+            stats = r.get("stats", {}) or {}
+            for k in stat_keys:
+                val = stats.get(k)
+                if isinstance(stats_out[k], dict):
+                    agent_dict = val if isinstance(val, dict) else {}
+                    for ak in stats_out[k].keys():
+                        stats_out[k][ak].append(agent_dict.get(ak))
+                else:
+                    stats_out[k].append(val)
+
+        with open(outfile, "w", encoding="utf-8") as w:
+            json.dump(
+                {
+                    "mgid": mgids,
+                    "crn_id": crn_ids,
+                    "iteration": iterations_out,
+                    "stats": stats_out,
+                },
+                w,
+                ensure_ascii=False,
+            )
+
+    return outfile

src_code_for_reproducibility/models/__init__.py

@@ -0,0 +1,4 @@
+"""
+File: mllm/models/__init__.py
+Summary: Exports model-layer utilities from the models package.
+"""

src_code_for_reproducibility/models/adapter_training_wrapper.py

@@ -0,0 +1,104 @@
+"""
+File: mllm/models/adapter_training_wrapper.py
+Summary: Wraps a shared LLM with adapter-specific PEFT handling for training.
+"""
+
+import logging
+from typing import Union
+
+import torch
+import torch.nn as nn
+from peft import LoraConfig, get_peft_model
+
+logger = logging.getLogger(__name__)
+
+
+class AdapterWrapper(nn.Module):
+    """
+    A thin façade that
+      • keeps a reference to a *shared* PEFT-wrapped model,
+      • ensures `set_adapter(adapter)` is called on every forward,
+      • exposes only the parameters that should be trained for that adapter
+        (plus whatever extra modules you name).
+    """
+
+    def __init__(
+        self,
+        shared_llm: nn.Module,
+        adapter_id: str,
+        lora_config: dict,
+        path: Union[str, None] = None,
+    ):
+        super().__init__()
+        self.shared_llm = shared_llm
+        self.adapter_id = adapter_id
+        lora_config = LoraConfig(**lora_config)
+        # this modifies the shared llm in place, adding a lora adapter inside
+        self.shared_llm = get_peft_model(
+            model=shared_llm,
+            peft_config=lora_config,
+            adapter_name=adapter_id,
+        )
+        self.shared_llm.train()
+        # Load external adapter weights if provided
+        loaded_from: str | None = None
+        if path:
+            try:
+                # Supports both local filesystem paths and HF Hub repo IDs
+                self.shared_llm.load_adapter(
+                    is_trainable=True,
+                    model_id=path,
+                    adapter_name=adapter_id,
+                )
+                loaded_from = path
+            except (
+                Exception
+            ) as exc:  # noqa: BLE001 - want to log any load failure context
+                logger.warning(
+                    f"Adapter '{adapter_id}': failed to load from '{path}': {exc}"
+                )
+
+        if loaded_from:
+            logger.info(
+                f"Adapter '{adapter_id}': loaded initial weights from '{loaded_from}'."
+            )
+        else:
+            logger.info(
+                f"Adapter '{adapter_id}': initialized with fresh weights (no initial weights found)."
+            )
+
+    def parameters(self, recurse: bool = True):
+        """
+        "recurse" is just for pytorch compatibility
+        """
+        self.shared_llm.set_adapter(self.adapter_id)
+        params = [p for p in self.shared_llm.parameters() if p.requires_grad]
+
+        return params
+
+    def get_base_model_logits(self, contexts):
+        """
+        Run the base model (without adapter) in inference mode, without tracking gradients.
+        This is useful to get reference logits for KL-divergence computation.
+        """
+        with torch.no_grad():
+            with self.shared_llm.disable_adapter():
+                return self.shared_llm(input_ids=contexts)[0]
+
+    def forward(self, *args, **kwargs):
+        self.shared_llm.set_adapter(self.adapter_id)
+        return self.shared_llm(*args, **kwargs)
+
+    def save_pretrained(self, save_path):
+        self.shared_llm.save_pretrained(save_path)
+
+    def gradient_checkpointing_enable(self, *args, **kwargs):
+        self.shared_llm.gradient_checkpointing_enable(*args, **kwargs)
+
+    @property
+    def dtype(self):
+        return self.shared_llm.dtype
+
+    @property
+    def device(self):
+        return self.shared_llm.device

src_code_for_reproducibility/models/human_policy.py

@@ -0,0 +1,260 @@
+"""
+File: mllm/models/human_policy.py
+Summary: Implements an interactive human-in-the-loop policy for experiments.
+"""
+
+import asyncio
+import os
+import re
+import shutil
+import sys
+from typing import Callable, Dict, List, Optional
+
+from mllm.markov_games.rollout_tree import ChatTurn
+
+try:
+    import rstr  # For generating example strings from regex
+except Exception:  # pragma: no cover
+    rstr = None
+
+
+def _clear_terminal() -> None:
+    """
+    Clear the terminal screen in a cross-platform manner.
+    """
+    if sys.stdout.isatty():
+        os.system("cls" if os.name == "nt" else "clear")
+
+
+def _terminal_width(default: int = 100) -> int:
+    try:
+        return shutil.get_terminal_size().columns
+    except Exception:
+        return default
+
+
+def _horizontal_rule(char: str = "─") -> str:
+    width = max(20, _terminal_width() - 2)
+    return char * width
+
+
+class _Style:
+    # ANSI colors (bright, readable)
+    RESET = "\033[0m"
+    BOLD = "\033[1m"
+    DIM = "\033[2m"
+    # Foreground colors
+    FG_BLUE = "\033[94m"  # user/system headers
+    FG_GREEN = "\033[92m"  # human response header
+    FG_YELLOW = "\033[93m"  # notices
+    FG_RED = "\033[91m"  # errors
+    FG_MAGENTA = "\033[95m"  # regex
+    FG_CYAN = "\033[96m"  # tips
+
+
+def _render_chat(state) -> str:
+    """
+    Render prior messages in a compact, readable terminal format.
+
+    Expected message dict keys: {"role": str, "content": str, ...}
+    """
+    lines: List[str] = []
+    lines.append(_horizontal_rule())
+    lines.append(f"{_Style.FG_BLUE}{_Style.BOLD} Conversation so far {_Style.RESET}")
+    lines.append(_horizontal_rule())
+    for chat in state:
+        role = chat.role
+        content = str(chat.content).strip()
+        # Map roles to display names and colors/emojis
+        if role == "assistant":
+            header = f"{_Style.FG_GREEN}{_Style.BOLD}HUMAN--🧑‍💻{_Style.RESET}"
+        elif role == "user":
+            header = f"{_Style.FG_BLUE}{_Style.BOLD}USER--⚙️{_Style.RESET}"
+        else:
+            header = f"[{_Style.DIM}{role.upper()}{_Style.RESET}]"
+        lines.append(header)
+        # Indent content for readability
+        for line in content.splitlines() or [""]:
+            lines.append(f"  {line}")
+        lines.append("")
+    lines.append(_horizontal_rule())
+    return "\n".join(lines)
+
+
+async def _async_input(prompt_text: str) -> str:
+    """Non-blocking input using a background thread."""
+    return await asyncio.to_thread(input, prompt_text)
+
+
+def _short_regex_example(regex: str, max_len: int = 30) -> Optional[str]:
+    """
+    Try to produce a short example string that matches the regex.
+    We attempt multiple times and pick the first <= max_len.
+    """
+    if rstr is None:
+        return None
+    try:
+        for _ in range(20):
+            candidate = rstr.xeger(regex)
+            if len(candidate) <= max_len:
+                return candidate
+        # Fallback to truncation (may break match, so don't return)
+        return None
+    except Exception:
+        return None
+
+
+def _detect_input_type(regex: str | None) -> tuple[str, str, str]:
+    """
+    Detect what type of input is expected based on the regex pattern.
+    Returns (input_type, start_tag, end_tag)
+    """
+    if regex is None:
+        return "text", "", ""
+
+    if "message_start" in regex and "message_end" in regex:
+        return "message", "<<message_start>>", "<<message_end>>"
+    elif "proposal_start" in regex and "proposal_end" in regex:
+        return "proposal", "<<proposal_start>>", "<<proposal_end>>"
+    else:
+        return "text", "", ""
+
+
+async def human_policy(state, agent_id, regex: str | None = None) -> str:
+    """
+    Async human-in-the-loop policy.
+
+    - Displays prior conversation context in the terminal.
+    - Prompts the user for a response.
+    - If a regex is provided, validates and re-prompts until it matches.
+    - Automatically adds formatting tags based on expected input type.
+
+    Args:
+        prompt: Chat history as a list of {role, content} dicts.
+        regex: Optional fullmatch validation pattern.
+
+    Returns:
+        The user's validated response string.
+    """
+    # Detect input type and formatting
+    input_type, start_tag, end_tag = _detect_input_type(regex)
+
+    while True:
+        _clear_terminal()
+        print(_render_chat(state))
+
+        if regex:
+            example = _short_regex_example(regex, max_len=30)
+            print(
+                f"{_Style.FG_MAGENTA}{_Style.BOLD}Expected format (regex fullmatch):{_Style.RESET}"
+            )
+            print(f"  {_Style.FG_MAGENTA}{regex}{_Style.RESET}")
+            if example:
+                print(
+                    f"{_Style.FG_CYAN}Example (random, <=30 chars):{_Style.RESET} {example}"
+                )
+            print(_horizontal_rule("."))
+
+            # Custom prompt based on input type
+            if input_type == "message":
+                print(
+                    f"{_Style.FG_YELLOW}Type your message content (formatting will be added automatically):{_Style.RESET}"
+                )
+            elif input_type == "proposal":
+                print(
+                    f"{_Style.FG_YELLOW}Type your proposal (number only, formatting will be added automatically):{_Style.RESET}"
+                )
+            else:
+                print(
+                    f"{_Style.FG_YELLOW}Type your response and press Enter.{_Style.RESET}"
+                )
+
+            print(
+                f"{_Style.DIM}Commands: /help to view commands, /refresh to re-render, /quit to abort{_Style.RESET}"
+            )
+        else:
+            print(
+                f"{_Style.FG_YELLOW}Type your response and press Enter.{_Style.RESET} {_Style.DIM}(/help for commands){_Style.RESET}"
+            )
+
+        user_in = (await _async_input("> ")).rstrip("\n")
+
+        # Commands
+        if user_in.strip().lower() in {"/help", "/h"}:
+            print(f"\n{_Style.FG_CYAN}{_Style.BOLD}Available commands:{_Style.RESET}")
+            print(
+                f"  {_Style.FG_CYAN}/help{_Style.RESET} or {_Style.FG_CYAN}/h{_Style.RESET}     Show this help"
+            )
+            print(
+                f"  {_Style.FG_CYAN}/refresh{_Style.RESET} or {_Style.FG_CYAN}/r{_Style.RESET}  Re-render the conversation and prompt"
+            )
+            print(
+                f"  {_Style.FG_CYAN}/quit{_Style.RESET} or {_Style.FG_CYAN}/q{_Style.RESET}     Abort the run (raises KeyboardInterrupt)"
+            )
+            await asyncio.sleep(1.0)
+            continue
+        if user_in.strip().lower() in {"/refresh", "/r"}:
+            continue
+        if user_in.strip().lower() in {"/quit", "/q"}:
+            raise KeyboardInterrupt("Human aborted run from human_policy")
+
+        # Add formatting tags if needed
+        if start_tag and end_tag:
+            formatted_input = f"{start_tag}{user_in}{end_tag}"
+        else:
+            formatted_input = user_in
+
+        if regex is None:
+            return ChatTurn(
+                role="assistant", agent_id=agent_id, content=formatted_input
+            )
+
+        # Validate against regex (fullmatch)
+        try:
+            pattern = re.compile(regex)
+        except re.error as e:
+            # If regex is invalid, fall back to accepting any input
+            print(
+                f"{_Style.FG_RED}Warning:{_Style.RESET} Provided regex is invalid: {e}. Accepting input without validation."
+            )
+            await asyncio.sleep(0.5)
+            return ChatTurn(
+                role="assistant", agent_id=agent_id, content=formatted_input
+            )
+
+        if pattern.fullmatch(formatted_input):
+            return ChatTurn(
+                role="assistant", agent_id=agent_id, content=formatted_input
+            )
+
+        # Show validation error and re-prompt
+        print("")
+        print(
+            f"{_Style.FG_RED}{_Style.BOLD}Input did not match the required format.{_Style.RESET} Please try again."
+        )
+
+        if input_type == "message":
+            print(
+                f"You entered: {_Style.FG_CYAN}{start_tag}{user_in}{end_tag}{_Style.RESET}"
+            )
+            print(f"Just type the message content without tags.")
+        elif input_type == "proposal":
+            print(
+                f"You entered: {_Style.FG_CYAN}{start_tag}{user_in}{end_tag}{_Style.RESET}"
+            )
+            print(f"Just type the number without tags.")
+        else:
+            print(f"Expected (regex):")
+            print(f"  {_Style.FG_MAGENTA}{regex}{_Style.RESET}")
+
+        print(_horizontal_rule("."))
+        print(f"{_Style.FG_YELLOW}Press Enter to retry...{_Style.RESET}")
+        await _async_input("")
+
+
+def get_human_policies() -> Dict[str, Callable[[List[Dict]], str]]:
+    """
+    Expose the human policy in the same map shape used elsewhere.
+    """
+    # Type hint says Callable[[List[Dict]], str] but we intentionally return the async callable.
+    return {"human_policy": human_policy}  # type: ignore[return-value]

src_code_for_reproducibility/models/inference_backend.py

@@ -0,0 +1,44 @@
+"""
+File: mllm/models/inference_backend.py
+Summary: Declares the inference backend interface and shared dataclasses.
+"""
+
+from abc import ABC, abstractmethod
+from dataclasses import dataclass
+from typing import Any, Optional
+
+
+@dataclass
+class LLMInferenceOutput:
+    content: str
+    reasoning_content: str | None = None
+    log_probs: list[float] | None = None
+    out_token_ids: list[int] | None = None
+
+
+class LLMInferenceBackend(ABC):
+    @abstractmethod
+    def __init__(self, **kwargs):
+        ...
+
+    @abstractmethod
+    def prepare_adapter(
+        self, adapter_id: str, weights_got_updated: bool = False
+    ) -> None:
+        """Ensure adapter is ready/loaded for next generation call."""
+
+    @abstractmethod
+    async def generate(self, prompt: list[dict], regex: Optional[str] = None) -> str:
+        ...
+
+    @abstractmethod
+    def toggle_training_mode(self) -> None:
+        ...
+
+    @abstractmethod
+    def toggle_eval_mode(self) -> None:
+        ...
+
+    @abstractmethod
+    def shutdown(self) -> None:
+        ...

src_code_for_reproducibility/models/inference_backend_dummy.py

@@ -0,0 +1,59 @@
+"""
+File: mllm/models/inference_backend_dummy.py
+Summary: Stub inference backend that returns synthetic completions for tests.
+"""
+
+import asyncio
+from typing import Optional
+
+import rstr
+from transformers import AutoTokenizer
+
+from mllm.models.inference_backend import LLMInferenceBackend, LLMInferenceOutput
+from mllm.utils.short_id_gen import generate_short_id
+
+
+class DummyInferenceBackend(LLMInferenceBackend):
+    def __init__(
+        self,
+        *args,
+        **kwargs,
+    ):
+        pass
+
+    def prepare_adapter(
+        self,
+        adapter_id: Optional[str],
+        weights_got_updated: bool,
+        adapter_path: Optional[str] = None,
+    ) -> None:
+        pass
+
+    async def toggle_training_mode(self) -> None:
+        await asyncio.sleep(0)
+        pass
+
+    async def toggle_eval_mode(self) -> None:
+        await asyncio.sleep(0)
+        pass
+
+    def shutdown(self) -> None:
+        pass
+
+    async def generate(
+        self,
+        prompt_text: str,
+        regex: Optional[str] = None,
+        extract_thinking: bool = False,
+    ) -> LLMInferenceOutput:
+        if regex:
+            # Create random string that respects the regex
+            return LLMInferenceOutput(
+                content=rstr.xeger(regex),
+                reasoning_content="I don't think, I am a dummy backend.",
+            )
+        else:
+            return LLMInferenceOutput(
+                content="I am a dummy backend without a regex.",
+                reasoning_content="I don't think, I am a dummy backend.",
+            )

src_code_for_reproducibility/models/inference_backend_vllm.py

@@ -0,0 +1,111 @@
+"""
+File: mllm/models/inference_backend_vllm.py
+Summary: Connects to in-process vLLM instances for batched generation.
+"""
+
+import asyncio
+import re
+from typing import Optional
+
+import torch
+from transformers import AutoTokenizer
+from vllm import AsyncEngineArgs, AsyncLLMEngine, SamplingParams
+from vllm.inputs import TokensPrompt
+from vllm.lora.request import LoRARequest
+from vllm.sampling_params import GuidedDecodingParams, RequestOutputKind
+
+from mllm.models.inference_backend import LLMInferenceBackend, LLMInferenceOutput
+from mllm.utils.short_id_gen import generate_short_id
+
+
+class VLLMAsyncBackend(LLMInferenceBackend):
+    def __init__(
+        self,
+        model_name: str,
+        tokenizer: AutoTokenizer,
+        # adapter_paths: dict[str, str],
+        engine_init_kwargs: dict = {},
+        sampling_params: dict = {},
+    ):
+        self.model_name = model_name
+        self.vllm_adapter_ids = {}
+        ea = dict(model=model_name, **engine_init_kwargs)
+        self.engine = AsyncLLMEngine.from_engine_args(AsyncEngineArgs(**ea))
+
+        self.sampling_params = sampling_params
+        self.tokenizer = tokenizer
+
+    def prepare_adapter(
+        self,
+        adapter_id: Optional[str],
+        adapter_path: Optional[str],
+        weights_got_updated: bool,
+    ) -> None:
+        if weights_got_updated:
+            self.vllm_adapter_ids[adapter_id] = generate_short_id()
+        self.current_lora_request = LoRARequest(
+            adapter_id,
+            self.vllm_adapter_ids[adapter_id],
+            adapter_path,
+        )
+
+    async def toggle_training_mode(self) -> None:
+        await self.engine.sleep(level=1)
+
+    async def toggle_eval_mode(self) -> None:
+        await self.engine.wake_up()
+
+    def shutdown(self) -> None:
+        # No explicit close call; engine stops when process exits.
+        pass
+
+    async def generate(
+        self,
+        input_token_ids: list[int],
+        regex: Optional[str] = None,
+        extract_thinking: bool = False,
+    ) -> LLMInferenceOutput:
+        # Build SamplingParams correctly
+        guided = GuidedDecodingParams(regex=regex) if regex else None
+        sp = SamplingParams(
+            **self.sampling_params,
+            guided_decoding=guided,
+            output_kind=RequestOutputKind.FINAL_ONLY,
+        )
+
+        prompt = TokensPrompt(prompt_token_ids=input_token_ids)
+        request_id = f"req-{asyncio.get_running_loop().time()}"
+        result_generator = self.engine.generate(
+            prompt,
+            sp,  # SamplingParams(...)
+            request_id,
+            lora_request=self.current_lora_request,
+        )
+
+        async for out in result_generator:  # with FINAL_ONLY this runs once
+            res = out
+
+        raw_text = res.outputs[0].text
+        out_token_ids = res.outputs[0].token_ids
+        log_probs = [
+            logprob_dict[token_id].logprob
+            for token_id, logprob_dict in zip(out_token_ids, res.outputs[0].logprobs)
+        ]
+        log_probs = torch.tensor(log_probs)
+        out_token_ids = torch.tensor(out_token_ids, dtype=torch.long)
+        content = raw_text
+        reasoning_content = None
+
+        if extract_thinking:
+            m = re.match(
+                r"^\n<think>\n([\s\S]*?)</think>\n\n(.*)$", raw_text, flags=re.DOTALL
+            )
+            if m:
+                reasoning_content = m.group(1)
+                content = m.group(2)
+        return LLMInferenceOutput(
+            content=content,
+            reasoning_content=reasoning_content,
+            log_probs=log_probs,
+            out_token_ids=out_token_ids,
+        )

src_code_for_reproducibility/models/large_language_model_api.py

@@ -0,0 +1,174 @@
+"""
+File: mllm/models/large_language_model_api.py
+Summary: Implements API-based large-language-model inference adapters.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import copy
+import os
+import random
+import re
+from typing import Any, Callable, Dict, List, Optional, Sequence
+
+import backoff
+from openai import AsyncOpenAI, OpenAIError
+
+from mllm.markov_games.rollout_tree import ChatTurn
+from mllm.models.inference_backend import LLMInferenceOutput
+
+# Static list copied from the public OpenAI docs until a discovery endpoint is exposed.
+reasoning_models = [
+    "gpt-5-nano",
+    "gpt-5-mini",
+    "gpt-5",
+    "o1-mini",
+    "o1",
+    "o1-pro",
+    "o3-mini",
+    "o3",
+    "o3-pro",
+    "o4-mini",
+    "o4",
+    "o4-pro",
+]
+
+
+class LargeLanguageModelOpenAI:
+    """Tiny async wrapper for OpenAI Chat Completions."""
+
+    def __init__(
+        self,
+        llm_id: str = "",
+        model: str = "gpt-4.1-mini",
+        api_key: Optional[str] = None,
+        base_url: Optional[str] = None,
+        timeout_s: float = 300.0,
+        regex_max_attempts: int = 10,
+        sampling_params: Optional[Dict[str, Any]] = None,
+        init_kwargs: Optional[Dict[str, Any]] = None,
+        output_directory: Optional[str] = None,
+    ) -> None:
+        self.llm_id = llm_id
+        self.model = model
+        key = api_key or os.getenv("OPENAI_API_KEY")
+        if not key:
+            raise RuntimeError(
+                "Set OPENAI_API_KEY as global environment variable or pass api_key."
+            )
+        client_kwargs: Dict[str, Any] = {"api_key": key, "timeout": timeout_s}
+        if base_url:
+            client_kwargs["base_url"] = base_url
+        self.client = AsyncOpenAI(**client_kwargs)
+
+        # Sampling/default request params set at init
+        self.sampling_params = sampling_params
+        self.use_reasoning = model in reasoning_models
+        if self.use_reasoning:
+            self.sampling_params["reasoning"] = {
+                "effort": "low",
+                "summary": "detailed",
+            }
+        self.regex_max_attempts = max(1, int(regex_max_attempts))
+
+    def get_inference_policies(self) -> Dict[str, Callable]:
+        return {
+            self.llm_id: self.get_action,
+        }
+
+    async def prepare_adapter_for_inference(self, *args: Any, **kwargs: Any) -> None:
+        await asyncio.sleep(0)
+        pass
+
+    async def toggle_eval_mode(self, *args: Any, **kwargs: Any) -> None:
+        await asyncio.sleep(0)
+        pass
+
+    async def toggle_training_mode(self, *args: Any, **kwargs: Any) -> None:
+        await asyncio.sleep(0)
+        pass
+
+    async def export_adapters(self, *args: Any, **kwargs: Any) -> None:
+        await asyncio.sleep(0)
+        pass
+
+    async def checkpoint_all_adapters(self, *args: Any, **kwargs: Any) -> None:
+        await asyncio.sleep(0)
+        pass
+
+    def extract_output_from_response(self, resp: Response) -> LLMInferenceOutput:
+        if len(resp.output) > 1:
+            summary = resp.output[0].summary
+            if summary != []:
+                reasoning_content = summary[0].text
+                reasoning_content = f"OpenAI Reasoning Summary: {reasoning_content}"
+            else:
+                reasoning_content = None
+            content = resp.output[1].content[0].text
+        else:
+            reasoning_content = None
+            content = resp.output[0].content[0].text
+
+        return LLMInferenceOutput(
+            content=content,
+            reasoning_content=reasoning_content,
+        )
+
+    @backoff.on_exception(
+        backoff.expo, Exception, max_time=10**10, max_tries=10**10
+    )
+    async def get_action(
+        self,
+        state: list[ChatTurn],
+        agent_id: str,
+        regex: Optional[str] = None,
+    ) -> LLMInferenceOutput:
+        # Remove any non-role/content keys from the prompt else openai will error.
+        prompt = [{"role": p.role, "content": p.content} for p in state]
+
+        # if self.sleep_between_requests:
+        #     await self.wait_random_time()
+
+        # If regex is required, prime the model and validate client-side
+        if regex:
+            constraint_msg = {
+                "role": "user",
+                "content": (
+                    f"Output must match this regex exactly: {regex} \n"
+                    "Return only the matching string, with no quotes or extra text."
+                ),
+            }
+            prompt = [constraint_msg, *prompt]
+            pattern = re.compile(regex)
+            for _ in range(self.regex_max_attempts):
+                resp = await self.client.responses.create(
+                    model=self.model,
+                    input=prompt,
+                    **self.sampling_params,
+                )
+                policy_output = self.extract_output_from_response(resp)
+                if pattern.fullmatch(policy_output.content):
+                    return policy_output
+                prompt = [
+                    *prompt,
+                    {
+                        "role": "user",
+                        "content": (
+                            f"Invalid response format. Expected format (regex): {regex}\n Please try again and provide ONLY a response that matches this regex."
+                        ),
+                    },
+                ]
+            return policy_output
+
+        # Simple, unconstrained generation
+        resp = await self.client.responses.create(
+            model=self.model,
+            input=prompt,
+            **self.sampling_params,
+        )
+        policy_output = self.extract_output_from_response(resp)
+        return policy_output
+
+    def shutdown(self) -> None:
+        self.client = None

src_code_for_reproducibility/models/large_language_model_local.py

@@ -0,0 +1,361 @@
+"""
+File: mllm/models/large_language_model_local.py
+Summary: Provides a local large language model wrapper over inference backends.
+"""
+
+import logging
+import os
+import re
+import sys
+import uuid
+from collections.abc import Callable
+from copy import deepcopy
+from datetime import datetime
+from typing import Literal
+
+import httpx
+import requests
+import torch
+import torch.nn as nn
+from torch.optim import SGD, Adam, AdamW, RMSprop
+from transformers import AutoModelForCausalLM, AutoTokenizer
+
+from mllm.chat_utils.apply_template import chat_turns_to_token_ids
+from mllm.markov_games.rollout_tree import ChatTurn
+from mllm.models.adapter_training_wrapper import AdapterWrapper
+from mllm.models.inference_backend import LLMInferenceOutput
+from mllm.models.inference_backend_dummy import DummyInferenceBackend
+from mllm.models.inference_backend_vllm import VLLMAsyncBackend
+
+logger = logging.getLogger(__name__)
+logger.addHandler(logging.StreamHandler(sys.stdout))
+
+AdapterID = str
+PolicyID = str
+
+
+class LeanLocalLLM:
+    """
+    Wrapper that manages local HuggingFace models, adapters, and inference backends.
+    """
+
+    def __init__(
+        self,
+        llm_id: str = "base_llm",
+        model_name: str = "Qwen/Qwen3-4B-Instruct-2507",
+        device: str = "cuda",
+        hf_kwargs: dict = {},
+        adapter_configs: dict = {},
+        output_directory: str = "./models/",
+        inference_backend: Literal["vllm", "dummy"] = "vllm",
+        inference_backend_sampling_params: dict = {},
+        inference_backend_init_kwargs: dict = {},
+        initial_adapter_paths: dict[str, str] | None = None,
+        initial_buffer_paths: list[str] | None = None,
+        enable_thinking: bool = None,
+        regex_max_attempts: int = -1,
+        max_thinking_characters: int = 0,
+    ):
+        self.inference_backend_name = inference_backend
+        self.output_directory = output_directory
+        self.llm_id = llm_id
+        self.device = torch.device(device) if device else torch.device("cuda")
+        self.model_name = model_name
+        self.adapter_configs = adapter_configs
+        self.adapter_ids = list(adapter_configs.keys())
+        self.enable_thinking = enable_thinking
+        self.regex_max_attempts = regex_max_attempts
+        self.initial_buffer_paths = initial_buffer_paths
+        self.max_thinking_characters = max_thinking_characters
+        self.regex_retries_count = 0
+
+        # Optional user-specified initial adapter weight locations (local or HF Hub)
+        # Format: {adapter_id: path_or_repo_id}
+        self.initial_adapter_paths: dict[str, str] | None = initial_adapter_paths
+
+        # Path management / imports
+        self.save_path = str(os.path.join(output_directory, model_name, "adapters"))
+        self.adapter_paths = {
+            adapter_id: os.path.join(self.save_path, adapter_id)
+            for adapter_id in self.adapter_ids
+        }
+        checkpoints_dir = os.path.join(self.output_directory, "checkpoints")
+        self.past_agent_adapter_paths = {}
+        if os.path.isdir(checkpoints_dir):
+            for dirname in os.listdir(checkpoints_dir):
+                dirpath = os.path.join(checkpoints_dir, dirname)
+                if os.path.isdir(dirpath):
+                    self.past_agent_adapter_paths[f"{dirname}_buffer"] = os.path.join(
+                        dirpath, "agent_adapter"
+                    )
+            logger.info(
+                f"Loaded {len(self.past_agent_adapter_paths)} past agent adapters from checkpoints directory."
+            )
+        if self.initial_buffer_paths is not None:
+            previous_count = len(self.past_agent_adapter_paths)
+            for path in self.initial_buffer_paths:
+                if os.path.isdir(path):
+                    for dirname in os.listdir(path):
+                        dirpath = os.path.join(path, dirname)
+                        if os.path.isdir(dirpath):
+                            self.past_agent_adapter_paths[
+                                f"{dirname}_buffer"
+                            ] = os.path.join(dirpath, "agent_adapter")
+                else:
+                    logger.warning(
+                        f"Initial buffer path {path} does not exist or is not a directory."
+                    )
+            logger.info(
+                f"Loaded {len(self.past_agent_adapter_paths) - previous_count} past agent adapters from user-specified initial buffer paths."
+            )
+        self.past_agent_adapter_ids = list(self.past_agent_adapter_paths.keys())
+
+        # ID management for tracking adapter versions
+        self.adapter_train_ids = {
+            adapter_id: self.short_id_generator() for adapter_id in self.adapter_ids
+        }
+        # Initialize tokenizer
+        self.tokenizer = AutoTokenizer.from_pretrained(self.model_name)
+        # Setup padding token to be same as EOS token
+        self.tokenizer.pad_token_id = self.tokenizer.eos_token_id
+        self.tokenizer.pad_token = self.tokenizer.eos_token
+
+        self.weights_got_updated: dict[AdapterID, bool] = {
+            adapter_id: False for adapter_id in self.adapter_ids
+        }
+        self.weights_got_updated.update(
+            {adapter_id: False for adapter_id in self.past_agent_adapter_ids}
+        )
+        self.current_lora_request = None
+        self.currently_loaded_adapter_id = None
+
+        # ---------------------------------------------------------
+        # Init HF model, peft adapters
+        # ---------------------------------------------------------
+        self.shared_hf_llm = AutoModelForCausalLM.from_pretrained(
+            pretrained_model_name_or_path=model_name,
+            **hf_kwargs,
+        )
+        self.hf_adapters = {}
+        self.optimizers = {}
+        for adapter_id in self.adapter_ids:
+            # Prefer output-folder path if it exists; else fall back to user-specified initial path if provided
+            output_path = os.path.join(self.save_path, adapter_id)
+            chosen_path: str | None = None
+            if os.path.isdir(output_path) and os.listdir(output_path):
+                chosen_path = output_path
+                logger.info(
+                    f"Initializing adapter '{adapter_id}': using existing weights from output folder '{chosen_path}'."
+                )
+            elif (
+                self.initial_adapter_paths and adapter_id in self.initial_adapter_paths
+            ):
+                chosen_path = self.initial_adapter_paths[adapter_id]
+                logger.info(
+                    f"Initializing adapter '{adapter_id}': using provided initial path '{chosen_path}'."
+                )
+            else:
+                logger.info(
+                    f"Initializing adapter '{adapter_id}': no initial weights provided or found; starting from scratch."
+                )
+            hf_adapter = AdapterWrapper(
+                shared_llm=self.shared_hf_llm,
+                adapter_id=adapter_id,
+                lora_config=adapter_configs[adapter_id],
+                path=chosen_path,
+            ).to(device)
+            self.hf_adapters[adapter_id] = hf_adapter
+        # Persist current state of all adapters (ensures remote loads are cached to disk)
+        self.export_adapters()
+
+        # ---------------------------------------------------------
+        # Init inference inference_backend
+        # ---------------------------------------------------------
+
+        if inference_backend == "vllm":
+            self.inference_backend = VLLMAsyncBackend(
+                model_name=self.model_name,
+                # adapter_paths=self.adapter_paths,
+                tokenizer=self.tokenizer,
+                engine_init_kwargs=inference_backend_init_kwargs,
+                sampling_params=inference_backend_sampling_params,
+            )
+        elif inference_backend == "dummy":
+            self.inference_backend = DummyInferenceBackend()
+        else:
+            raise ValueError(f"Unknown inference_backend: {inference_backend}")
+
+    def reset_regex_retries_count(self) -> None:
+        self.regex_retries_count = 0
+
+    def get_inference_policies(self) -> dict[PolicyID, Callable]:
+        """
+        Build async policy callables keyed by adapter id for inference-only usage.
+        """
+        policies = {}
+        for adapter_id in self.adapter_ids:
+            # define policy func
+            async def policy(
+                state: list[ChatTurn],
+                agent_id: str,
+                regex: str | None = None,
+                _adapter_id=adapter_id,
+            ):
+                self.prepare_adapter_for_inference(adapter_id=_adapter_id)
+                response = await self.get_action(state, agent_id, regex)
+                return response
+
+            policies[self.llm_id + "/" + adapter_id] = policy
+
+        for adapter_id in self.past_agent_adapter_ids:
+            # define policy func
+            async def policy(
+                state: list[ChatTurn],
+                agent_id: str,
+                regex: str | None = None,
+                _adapter_id=adapter_id,
+            ):
+                self.prepare_adapter_for_inference(adapter_id=_adapter_id)
+                response = await self.get_action(state, agent_id, regex)
+                return response
+
+            policies[self.llm_id + "/" + adapter_id] = policy
+        return policies
+
+    def get_adapter_modules(self) -> dict[PolicyID, nn.Module]:
+        """
+        Returns wrappers over the adapters which allows them be
+        interfaced like regular PyTorch models.
+        AdapterWrapper lives in adapter_wrapper.py; the huggingface modules already wrap
+        parameters here, so we surface them directly until an extra shim is required.
+        """
+        trainable_objects = {an: self.hf_adapters[an] for an in self.adapter_ids}
+        return trainable_objects
+
+    async def toggle_training_mode(self) -> None:
+        for adn in self.adapter_ids:
+            self.adapter_train_ids[adn] = self.short_id_generator()
+        await self.inference_backend.toggle_training_mode()
+
+    async def toggle_eval_mode(self) -> None:
+        await self.inference_backend.toggle_eval_mode()
+
+    def prepare_adapter_for_inference(self, adapter_id: AdapterID) -> None:
+        self.inference_backend.prepare_adapter(
+            adapter_id,
+            adapter_path=self.adapter_paths.get(
+                adapter_id, self.past_agent_adapter_paths.get(adapter_id, None)
+            ),
+            weights_got_updated=self.weights_got_updated[adapter_id],
+        )
+        self.currently_loaded_adapter_id = adapter_id
+        self.weights_got_updated[adapter_id] = False
+
+    # def _make_prompt_text(self, prompt: list[dict]) -> str:
+    #     if self.enable_thinking is not None:
+    #         prompt_text = self.tokenizer.apply_chat_template(
+    #             prompt,
+    #             tokenize=False,
+    #             add_generation_prompt=True,
+    #             enable_thinking=self.enable_thinking,
+    #         )
+    #     else:
+    #         prompt_text = self.tokenizer.apply_chat_template(
+    #             prompt,
+    #             tokenize=False,
+    #             add_generation_prompt=True,
+    #         )
+
+    #     return prompt_text
+
+    async def get_action(
+        self, state: list[ChatTurn], agent_id: str, regex: str | None = None
+    ) -> ChatTurn:
+        current_regex = regex if self.regex_max_attempts == -1 else None
+        pattern = re.compile(regex) if regex else None
+        nb_attempts = 0
+        state = state[:]
+        while True:
+            context_token_ids = chat_turns_to_token_ids(
+                chats=state,
+                tokenizer=self.tokenizer,
+                enable_thinking=self.enable_thinking,
+            )
+            policy_output = await self.inference_backend.generate(
+                input_token_ids=context_token_ids.tolist(),
+                extract_thinking=(self.max_thinking_characters > 0),
+                regex=current_regex,
+            )
+            if (
+                pattern is None
+                or (pattern.fullmatch(policy_output.content))
+                or (nb_attempts >= self.regex_max_attempts)
+            ):
+                return ChatTurn(
+                    agent_id=agent_id,
+                    role="assistant",
+                    content=policy_output.content,
+                    reasoning_content=policy_output.reasoning_content,
+                    out_token_ids=policy_output.out_token_ids,
+                    log_probs=policy_output.log_probs,
+                    is_state_end=False,
+                )
+            else:
+                self.regex_retries_count += 1
+                nb_attempts += 1
+                logger.warning(
+                    f"Response {policy_output.content} did not match regex: {regex}, retry {nb_attempts}/{self.regex_max_attempts}"
+                )
+                if nb_attempts == self.regex_max_attempts:
+                    current_regex = regex
+                # regex_prompt = ChatTurn(
+                #     role="user",
+                #     content=f"Invalid response format. Expected format (regex): {current_regex}\n Please try again and provide ONLY a response that matches this regex.",
+                #     reasoning_content=None,
+                #     log_probs=None,
+                #     out_token_ids=None,
+                #     is_state_end=False,
+                # )
+                # state.append(regex_prompt)
+
+    def export_adapters(self) -> None:
+        """
+        Any peft wrapper, by default, saves all adapters, not just the one currently loaded.
+        """
+
+        # New version of the adapters available
+        for adapter_id in self.adapter_ids:
+            self.weights_got_updated[adapter_id] = True
+        for adapter_id in self.past_agent_adapter_ids:
+            self.weights_got_updated[adapter_id] = True
+
+        adapter_id = self.adapter_ids[0]
+        self.hf_adapters[adapter_id].save_pretrained(self.save_path)
+
+    def checkpoint_all_adapters(self, checkpoint_indicator: str) -> None:
+        """
+        Checkpoints all adapters to the configured output directory.
+        """
+        adapter_id = self.adapter_ids[0]
+        output_dir = os.path.join(self.output_directory, "checkpoints")
+        os.makedirs(output_dir, exist_ok=True)
+        date_str = datetime.now().strftime("%Y-%m-%d_%H-%M-%S")
+        agent_adapter_dir = f"{adapter_id}-{checkpoint_indicator}-{date_str}"
+        export_path = os.path.join(output_dir, agent_adapter_dir)
+        for adapter_id in self.adapter_ids:
+            if "agent" in adapter_id:
+                self.past_agent_adapter_paths[
+                    f"{agent_adapter_dir}_buffer"
+                ] = os.path.join(export_path, adapter_id)
+                self.past_agent_adapter_ids.append(f"{agent_adapter_dir}_buffer")
+                self.weights_got_updated[f"{agent_adapter_dir}_buffer"] = False
+                self.hf_adapters[adapter_id].save_pretrained(export_path)
+
+    def short_id_generator(self) -> str:
+        """
+        Generates a short unique ID for tracking adapter versions.
+
+        Returns:
+            int: An 8-digit integer ID.
+        """
+        return str(uuid.uuid4().int)[:8]

src_code_for_reproducibility/models/scalar_critic.py

@@ -0,0 +1,59 @@
+"""
+File: mllm/models/scalar_critic.py
+Summary: Defines a scalar critic network and helper utilities.
+"""
+
+import torch
+import torch.nn as nn
+import torch.optim as optim
+from peft import LoraConfig, get_peft_model
+from transformers import AutoModelForCausalLM, AutoTokenizer
+
+from mllm.models.adapter_training_wrapper import AdapterWrapper
+
+
+class ScalarCritic(nn.Module):
+    """
+    A causal-LM critic_adapter + a scalar value head:
+        V_φ(s) = wᵀ h_last + b
+    Only LoRA adapters (inside critic_adapter) and the value head are trainable.
+    """
+
+    def __init__(self, critic_adapter: AdapterWrapper):
+        super().__init__()
+        self.critic_adapter = critic_adapter
+        hidden_size = self.critic_adapter.shared_llm.config.hidden_size
+        self.value_head = nn.Linear(hidden_size, 1).to(
+            dtype=critic_adapter.dtype, device=critic_adapter.device
+        )
+
+    def forward(self, input_ids, attention_mask=None, **kwargs):
+        # AdapterWrapper activates its own adapter internally
+        outputs = self.critic_adapter(
+            input_ids=input_ids,
+            attention_mask=attention_mask,
+            output_hidden_states=True,
+            **kwargs,
+        )
+        h_last = outputs.hidden_states[-1]  # (B, S, H)
+        values = self.value_head(h_last).squeeze(-1)  # (B, S)
+        return values
+
+    def parameters(self, recurse: bool = True):
+        """Iterator over *trainable* parameters for this critic."""
+        # 1) LoRA params for *this* adapter
+        for p in self.critic_adapter.parameters():
+            yield p
+        # 2) scalar head
+        yield from self.value_head.parameters()
+
+    def gradient_checkpointing_enable(self, *args, **kwargs):
+        self.critic_adapter.gradient_checkpointing_enable(*args, **kwargs)
+
+    @property
+    def dtype(self):
+        return self.critic_adapter.dtype
+
+    @property
+    def device(self):
+        return self.critic_adapter.device

src_code_for_reproducibility/training/__init__.py

@@ -0,0 +1,4 @@
+"""
+File: mllm/training/__init__.py
+Summary: Exposes training submodules through the package namespace.
+"""