ml-intern / agent /core /agent_loop.py
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akseljoonas HF Staff
fix: clear pending_approval before tool execution starts
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"""loop
Main agent implementation with integrated tool system and MCP support
"""
import asyncio
import json
import logging
import os
from litellm import ChatCompletionMessageToolCall, Message, acompletion
from litellm.exceptions import ContextWindowExceededError
from agent.config import Config
from agent.core.session import Event, OpType, Session
from agent.core.tools import ToolRouter
from agent.tools.jobs_tool import CPU_FLAVORS
logger = logging.getLogger(__name__)
ToolCall = ChatCompletionMessageToolCall
# Explicit inference token for LLM API calls (separate from user OAuth tokens).
_INFERENCE_API_KEY = os.environ.get("INFERENCE_TOKEN")
def _resolve_hf_router_params(model_name: str) -> dict:
"""
Build LiteLLM kwargs for HuggingFace Router models.
api-inference.huggingface.co is deprecated; the new router lives at
router.huggingface.co/<provider>/v3/openai. LiteLLM's built-in
``huggingface/`` provider still targets the old endpoint, so we
rewrite model names to ``openai/`` and supply the correct api_base.
Input format: huggingface/<router_provider>/<org>/<model>
Example: huggingface/novita/moonshotai/kimi-k2.5
"""
if not model_name.startswith("huggingface/"):
return {"model": model_name}
parts = model_name.split(
"/", 2
) # ['huggingface', 'novita', 'moonshotai/kimi-k2.5']
if len(parts) < 3:
return {"model": model_name}
router_provider = parts[1]
actual_model = parts[2]
api_key = _INFERENCE_API_KEY
return {
"model": f"openai/{actual_model}",
"api_base": f"https://router.huggingface.co/{router_provider}/v3/openai",
"api_key": api_key,
}
def _validate_tool_args(tool_args: dict) -> tuple[bool, str | None]:
"""
Validate tool arguments structure.
Returns:
(is_valid, error_message)
"""
args = tool_args.get("args", {})
# Sometimes LLM passes args as string instead of dict
if isinstance(args, str):
return (
False,
f"Tool call error: 'args' must be a JSON object, not a string. You passed: {repr(args)}",
)
if not isinstance(args, dict) and args is not None:
return (
False,
f"Tool call error: 'args' must be a JSON object. You passed type: {type(args).__name__}",
)
return True, None
def _needs_approval(
tool_name: str, tool_args: dict, config: Config | None = None
) -> bool:
"""Check if a tool call requires user approval before execution."""
# Yolo mode: skip all approvals
if config and config.yolo_mode:
return False
# If args are malformed, skip approval (validation error will be shown later)
args_valid, _ = _validate_tool_args(tool_args)
if not args_valid:
return False
if tool_name == "sandbox_create":
return True
if tool_name == "hf_jobs":
operation = tool_args.get("operation", "")
if operation not in ["run", "uv", "scheduled run", "scheduled uv"]:
return False
# Check if this is a CPU-only job
# hardware_flavor is at top level of tool_args, not nested in args
hardware_flavor = (
tool_args.get("hardware_flavor")
or tool_args.get("flavor")
or tool_args.get("hardware")
or "cpu-basic"
)
is_cpu_job = hardware_flavor in CPU_FLAVORS
if is_cpu_job:
if config and not config.confirm_cpu_jobs:
return False
return True
return True
# Check for file upload operations (hf_private_repos or other tools)
if tool_name == "hf_private_repos":
operation = tool_args.get("operation", "")
if operation == "upload_file":
if config and config.auto_file_upload:
return False
return True
# Other operations (create_repo, etc.) always require approval
if operation in ["create_repo"]:
return True
# hf_repo_files: upload (can overwrite) and delete require approval
if tool_name == "hf_repo_files":
operation = tool_args.get("operation", "")
if operation in ["upload", "delete"]:
return True
# hf_repo_git: destructive operations require approval
if tool_name == "hf_repo_git":
operation = tool_args.get("operation", "")
if operation in [
"delete_branch",
"delete_tag",
"merge_pr",
"create_repo",
"update_repo",
]:
return True
return False
async def _compact_and_notify(session: Session) -> None:
"""Run compaction and send event if context was reduced."""
old_length = session.context_manager.context_length
tool_specs = session.tool_router.get_tool_specs_for_llm()
await session.context_manager.compact(
model_name=session.config.model_name,
tool_specs=tool_specs,
)
new_length = session.context_manager.context_length
if new_length != old_length:
await session.send_event(
Event(
event_type="compacted",
data={"old_tokens": old_length, "new_tokens": new_length},
)
)
class Handlers:
"""Handler functions for each operation type"""
@staticmethod
async def _abandon_pending_approval(session: Session) -> None:
"""Cancel pending approval tools when the user continues the conversation.
Injects rejection tool-result messages into the LLM context (so the
history stays valid) and notifies the frontend that those tools were
abandoned.
"""
tool_calls = session.pending_approval.get("tool_calls", [])
for tc in tool_calls:
tool_name = tc.function.name
abandon_msg = (
"Task abandoned — user continued the conversation without approving."
)
# Keep LLM context valid: every tool_call needs a tool result
tool_msg = Message(
role="tool",
content=abandon_msg,
tool_call_id=tc.id,
name=tool_name,
)
session.context_manager.add_message(tool_msg)
await session.send_event(
Event(
event_type="tool_state_change",
data={
"tool_call_id": tc.id,
"tool": tool_name,
"state": "abandoned",
},
)
)
session.pending_approval = None
logger.info("Abandoned %d pending approval tool(s)", len(tool_calls))
@staticmethod
async def run_agent(
session: Session, text: str, max_iterations: int = 300
) -> str | None:
"""
Handle user input (like user_input_or_turn in codex.rs:1291)
Returns the final assistant response content, if any.
"""
# Clear any stale cancellation flag from a previous run
session.reset_cancel()
# If there's a pending approval and the user sent a new message,
# abandon the pending tools so the LLM context stays valid.
if text and session.pending_approval:
await Handlers._abandon_pending_approval(session)
# Add user message to history only if there's actual content
if text:
user_msg = Message(role="user", content=text)
session.context_manager.add_message(user_msg)
# Send event that we're processing
await session.send_event(
Event(event_type="processing", data={"message": "Processing user input"})
)
# Agentic loop - continue until model doesn't call tools or max iterations is reached
iteration = 0
final_response = None
errored = False
while iteration < max_iterations:
# ── Cancellation check: before LLM call ──
if session.is_cancelled:
break
# Compact before calling the LLM if context is near the limit
await _compact_and_notify(session)
messages = session.context_manager.get_messages()
tools = session.tool_router.get_tool_specs_for_llm()
try:
# ── Stream the LLM response ──────────────────────────
llm_params = _resolve_hf_router_params(session.config.model_name)
response = await acompletion(
messages=messages,
tools=tools,
tool_choice="auto",
stream=True,
stream_options={"include_usage": True},
**llm_params,
)
full_content = ""
tool_calls_acc: dict[int, dict] = {}
token_count = 0
finish_reason = None
async for chunk in response:
# ── Check cancellation during streaming ──
if session.is_cancelled:
tool_calls_acc.clear()
break
choice = chunk.choices[0] if chunk.choices else None
if not choice:
# Last chunk may carry only usage info
if hasattr(chunk, "usage") and chunk.usage:
token_count = chunk.usage.total_tokens
continue
delta = choice.delta
if choice.finish_reason:
finish_reason = choice.finish_reason
# Stream text deltas to the frontend
if delta.content:
full_content += delta.content
await session.send_event(
Event(
event_type="assistant_chunk",
data={"content": delta.content},
)
)
# Accumulate tool-call deltas (name + args arrive in pieces)
if delta.tool_calls:
for tc_delta in delta.tool_calls:
idx = tc_delta.index
if idx not in tool_calls_acc:
tool_calls_acc[idx] = {
"id": "",
"type": "function",
"function": {"name": "", "arguments": ""},
}
if tc_delta.id:
tool_calls_acc[idx]["id"] = tc_delta.id
if tc_delta.function:
if tc_delta.function.name:
tool_calls_acc[idx]["function"]["name"] += (
tc_delta.function.name
)
if tc_delta.function.arguments:
tool_calls_acc[idx]["function"]["arguments"] += (
tc_delta.function.arguments
)
# Capture usage from the final chunk
if hasattr(chunk, "usage") and chunk.usage:
token_count = chunk.usage.total_tokens
# ── Stream finished — reconstruct full message ───────
content = full_content or None
# If output was truncated, all tool call args are garbage
if finish_reason == "length" and tool_calls_acc:
logger.warning("Output truncated (finish_reason=length) — dropping tool calls")
tool_calls_acc.clear()
# Build tool_calls list from accumulated deltas
tool_calls: list[ToolCall] = []
for idx in sorted(tool_calls_acc.keys()):
tc_data = tool_calls_acc[idx]
tool_calls.append(
ToolCall(
id=tc_data["id"],
type="function",
function={
"name": tc_data["function"]["name"],
"arguments": tc_data["function"]["arguments"],
},
)
)
# Signal end of streaming to the frontend
await session.send_event(
Event(event_type="assistant_stream_end", data={})
)
# If no tool calls, add assistant message and we're done
if not tool_calls:
if content:
assistant_msg = Message(role="assistant", content=content)
session.context_manager.add_message(assistant_msg, token_count)
final_response = content
break
# Validate tool call args (one json.loads per call, once)
# and split into good vs bad
good_tools: list[tuple[ToolCall, str, dict]] = []
bad_tools: list[ToolCall] = []
for tc in tool_calls:
try:
args = json.loads(tc.function.arguments)
good_tools.append((tc, tc.function.name, args))
except (json.JSONDecodeError, TypeError, ValueError):
logger.warning(
"Malformed arguments for tool_call %s (%s) — skipping",
tc.id, tc.function.name,
)
tc.function.arguments = "{}"
bad_tools.append(tc)
# Add assistant message with all tool calls to context
assistant_msg = Message(
role="assistant",
content=content,
tool_calls=tool_calls,
)
session.context_manager.add_message(assistant_msg, token_count)
# Add error results for bad tool calls so the LLM
# knows what happened and can retry differently
for tc in bad_tools:
error_msg = (
f"ERROR: Tool call to '{tc.function.name}' had malformed JSON "
f"arguments and was NOT executed. Retry with smaller content — "
f"for 'write', split into multiple smaller writes using 'edit'."
)
session.context_manager.add_message(Message(
role="tool",
content=error_msg,
tool_call_id=tc.id,
name=tc.function.name,
))
await session.send_event(Event(
event_type="tool_call",
data={"tool": tc.function.name, "arguments": {}, "tool_call_id": tc.id},
))
await session.send_event(Event(
event_type="tool_output",
data={"tool": tc.function.name, "tool_call_id": tc.id, "output": error_msg, "success": False},
))
# ── Cancellation check: before tool execution ──
if session.is_cancelled:
break
# Separate good tools into approval-required vs auto-execute
approval_required_tools: list[tuple[ToolCall, str, dict]] = []
non_approval_tools: list[tuple[ToolCall, str, dict]] = []
for tc, tool_name, tool_args in good_tools:
if _needs_approval(tool_name, tool_args, session.config):
approval_required_tools.append((tc, tool_name, tool_args))
else:
non_approval_tools.append((tc, tool_name, tool_args))
# Execute non-approval tools (in parallel when possible)
if non_approval_tools:
# 1. Validate args upfront
parsed_tools: list[
tuple[ToolCall, str, dict, bool, str]
] = []
for tc, tool_name, tool_args in non_approval_tools:
args_valid, error_msg = _validate_tool_args(tool_args)
parsed_tools.append(
(tc, tool_name, tool_args, args_valid, error_msg)
)
# 2. Send all tool_call events upfront (so frontend shows them all)
for tc, tool_name, tool_args, args_valid, _ in parsed_tools:
if args_valid:
await session.send_event(
Event(
event_type="tool_call",
data={
"tool": tool_name,
"arguments": tool_args,
"tool_call_id": tc.id,
},
)
)
# 3. Execute all valid tools in parallel, cancellable
async def _exec_tool(
tc: ToolCall,
name: str,
args: dict,
valid: bool,
err: str,
) -> tuple[ToolCall, str, dict, str, bool]:
if not valid:
return (tc, name, args, err, False)
out, ok = await session.tool_router.call_tool(
name, args, session=session
)
return (tc, name, args, out, ok)
gather_task = asyncio.ensure_future(asyncio.gather(
*[
_exec_tool(tc, name, args, valid, err)
for tc, name, args, valid, err in parsed_tools
]
))
cancel_task = asyncio.ensure_future(session._cancelled.wait())
done, _ = await asyncio.wait(
[gather_task, cancel_task],
return_when=asyncio.FIRST_COMPLETED,
)
if cancel_task in done:
gather_task.cancel()
try:
await gather_task
except asyncio.CancelledError:
pass
break
cancel_task.cancel()
results = gather_task.result()
# 4. Record results and send outputs (order preserved)
for tc, tool_name, tool_args, output, success in results:
tool_msg = Message(
role="tool",
content=output,
tool_call_id=tc.id,
name=tool_name,
)
session.context_manager.add_message(tool_msg)
await session.send_event(
Event(
event_type="tool_output",
data={
"tool": tool_name,
"tool_call_id": tc.id,
"output": output,
"success": success,
},
)
)
# If there are tools requiring approval, ask for batch approval
if approval_required_tools:
# Prepare batch approval data
tools_data = []
for tc, tool_name, tool_args in approval_required_tools:
# Resolve sandbox file paths for hf_jobs scripts so the
# frontend can display & edit the actual file content.
if tool_name == "hf_jobs" and isinstance(tool_args.get("script"), str):
from agent.tools.sandbox_tool import resolve_sandbox_script
sandbox = getattr(session, "sandbox", None)
resolved, _ = await resolve_sandbox_script(sandbox, tool_args["script"])
if resolved:
tool_args = {**tool_args, "script": resolved}
tools_data.append({
"tool": tool_name,
"arguments": tool_args,
"tool_call_id": tc.id,
})
await session.send_event(Event(
event_type="approval_required",
data={"tools": tools_data, "count": len(tools_data)},
))
# Store all approval-requiring tools (ToolCall objects for execution)
session.pending_approval = {
"tool_calls": [tc for tc, _, _ in approval_required_tools],
}
# Return early - wait for EXEC_APPROVAL operation
return None
iteration += 1
except ContextWindowExceededError:
# Force compact and retry this iteration
session.context_manager.context_length = (
session.context_manager.max_context + 1
)
await _compact_and_notify(session)
continue
except Exception as e:
import traceback
await session.send_event(
Event(
event_type="error",
data={"error": str(e) + "\n" + traceback.format_exc()},
)
)
errored = True
break
if session.is_cancelled:
await session.send_event(Event(event_type="interrupted"))
elif not errored:
await session.send_event(
Event(
event_type="turn_complete",
data={"history_size": len(session.context_manager.items)},
)
)
# Increment turn counter and check for auto-save
session.increment_turn()
await session.auto_save_if_needed()
return final_response
@staticmethod
async def undo(session: Session) -> None:
"""Remove the last complete turn and notify the frontend."""
removed = session.context_manager.undo_last_turn()
if not removed:
logger.warning("Undo: no user message found to remove")
await session.send_event(Event(event_type="undo_complete"))
@staticmethod
async def exec_approval(session: Session, approvals: list[dict]) -> None:
"""Handle batch job execution approval"""
if not session.pending_approval:
await session.send_event(
Event(
event_type="error",
data={"error": "No pending approval to process"},
)
)
return
tool_calls = session.pending_approval.get("tool_calls", [])
if not tool_calls:
await session.send_event(
Event(
event_type="error",
data={"error": "No pending tool calls found"},
)
)
return
# Create a map of tool_call_id -> approval decision
approval_map = {a["tool_call_id"]: a for a in approvals}
for a in approvals:
if a.get("edited_script"):
logger.info(
f"Received edited script for tool_call {a['tool_call_id']} ({len(a['edited_script'])} chars)"
)
# Separate approved and rejected tool calls
approved_tasks = []
rejected_tasks = []
for tc in tool_calls:
tool_name = tc.function.name
try:
tool_args = json.loads(tc.function.arguments)
except (json.JSONDecodeError, TypeError) as e:
# Malformed arguments — treat as failed, notify agent
logger.warning(f"Malformed tool arguments for {tool_name}: {e}")
tool_msg = Message(
role="tool",
content=f"Malformed arguments: {e}",
tool_call_id=tc.id,
name=tool_name,
)
session.context_manager.add_message(tool_msg)
await session.send_event(
Event(
event_type="tool_output",
data={
"tool": tool_name,
"tool_call_id": tc.id,
"output": f"Malformed arguments: {e}",
"success": False,
},
)
)
continue
approval_decision = approval_map.get(tc.id, {"approved": False})
if approval_decision.get("approved", False):
edited_script = approval_decision.get("edited_script")
was_edited = False
if edited_script and "script" in tool_args:
tool_args["script"] = edited_script
was_edited = True
logger.info(f"Using user-edited script for {tool_name} ({tc.id})")
approved_tasks.append((tc, tool_name, tool_args, was_edited))
else:
rejected_tasks.append((tc, tool_name, approval_decision))
# Clear pending approval immediately so a page refresh during
# execution won't re-show the approval dialog.
session.pending_approval = None
# Notify frontend of approval decisions immediately (before execution)
for tc, tool_name, tool_args, _was_edited in approved_tasks:
await session.send_event(
Event(
event_type="tool_state_change",
data={
"tool_call_id": tc.id,
"tool": tool_name,
"state": "approved",
},
)
)
for tc, tool_name, approval_decision in rejected_tasks:
await session.send_event(
Event(
event_type="tool_state_change",
data={
"tool_call_id": tc.id,
"tool": tool_name,
"state": "rejected",
},
)
)
# Execute all approved tools concurrently
async def execute_tool(tc, tool_name, tool_args, was_edited):
"""Execute a single tool and return its result.
The TraceLog already exists on the frontend (created by
approval_required), so we send tool_state_change instead of
tool_call to avoid creating a duplicate.
"""
await session.send_event(
Event(
event_type="tool_state_change",
data={
"tool_call_id": tc.id,
"tool": tool_name,
"state": "running",
},
)
)
output, success = await session.tool_router.call_tool(
tool_name, tool_args, session=session, tool_call_id=tc.id
)
return (tc, tool_name, output, success, was_edited)
# Execute all approved tools concurrently and wait for ALL to complete
if approved_tasks:
results = await asyncio.gather(
*[
execute_tool(tc, tool_name, tool_args, was_edited)
for tc, tool_name, tool_args, was_edited in approved_tasks
],
return_exceptions=True,
)
# Process results and add to context
for result in results:
if isinstance(result, Exception):
# Handle execution error
logger.error(f"Tool execution error: {result}")
continue
tc, tool_name, output, success, was_edited = result
if was_edited:
output = f"[Note: The user edited the script before execution. The output below reflects the user-modified version, not your original script.]\n\n{output}"
# Add tool result to context
tool_msg = Message(
role="tool",
content=output,
tool_call_id=tc.id,
name=tool_name,
)
session.context_manager.add_message(tool_msg)
await session.send_event(
Event(
event_type="tool_output",
data={
"tool": tool_name,
"tool_call_id": tc.id,
"output": output,
"success": success,
},
)
)
# Process rejected tools
for tc, tool_name, approval_decision in rejected_tasks:
rejection_msg = "Job execution cancelled by user"
user_feedback = approval_decision.get("feedback")
if user_feedback:
# Ensure feedback is a string and sanitize any problematic characters
feedback_str = str(user_feedback).strip()
# Remove any control characters that might break JSON parsing
feedback_str = "".join(
char for char in feedback_str if ord(char) >= 32 or char in "\n\t"
)
rejection_msg += f". User feedback: {feedback_str}"
# Ensure rejection_msg is a clean string
rejection_msg = str(rejection_msg).strip()
tool_msg = Message(
role="tool",
content=rejection_msg,
tool_call_id=tc.id,
name=tool_name,
)
session.context_manager.add_message(tool_msg)
await session.send_event(
Event(
event_type="tool_output",
data={
"tool": tool_name,
"tool_call_id": tc.id,
"output": rejection_msg,
"success": False,
},
)
)
# Continue agent loop with empty input to process the tool results
await Handlers.run_agent(session, "")
@staticmethod
async def shutdown(session: Session) -> bool:
"""Handle shutdown (like shutdown in codex.rs:1329)"""
# Save session trajectory if enabled (fire-and-forget, returns immediately)
if session.config.save_sessions:
logger.info("Saving session...")
repo_id = session.config.session_dataset_repo
_ = session.save_and_upload_detached(repo_id)
session.is_running = False
await session.send_event(Event(event_type="shutdown"))
return True
async def process_submission(session: Session, submission) -> bool:
"""
Process a single submission and return whether to continue running.
Returns:
bool: True to continue, False to shutdown
"""
op = submission.operation
logger.debug("Received operation: %s", op.op_type.value)
if op.op_type == OpType.USER_INPUT:
text = op.data.get("text", "") if op.data else ""
await Handlers.run_agent(session, text)
return True
if op.op_type == OpType.COMPACT:
await _compact_and_notify(session)
return True
if op.op_type == OpType.UNDO:
await Handlers.undo(session)
return True
if op.op_type == OpType.EXEC_APPROVAL:
approvals = op.data.get("approvals", []) if op.data else []
await Handlers.exec_approval(session, approvals)
return True
if op.op_type == OpType.SHUTDOWN:
return not await Handlers.shutdown(session)
logger.warning(f"Unknown operation: {op.op_type}")
return True
async def submission_loop(
submission_queue: asyncio.Queue,
event_queue: asyncio.Queue,
config: Config | None = None,
tool_router: ToolRouter | None = None,
session_holder: list | None = None,
hf_token: str | None = None,
) -> None:
"""
Main agent loop - processes submissions and dispatches to handlers.
This is the core of the agent (like submission_loop in codex.rs:1259-1340)
"""
# Create session with tool router
session = Session(
event_queue, config=config, tool_router=tool_router, hf_token=hf_token
)
if session_holder is not None:
session_holder[0] = session
logger.info("Agent loop started")
# Retry any failed uploads from previous sessions (fire-and-forget)
if config and config.save_sessions:
Session.retry_failed_uploads_detached(
directory="session_logs", repo_id=config.session_dataset_repo
)
try:
# Main processing loop
async with tool_router:
# Emit ready event after initialization
await session.send_event(
Event(event_type="ready", data={"message": "Agent initialized"})
)
while session.is_running:
submission = await submission_queue.get()
try:
should_continue = await process_submission(session, submission)
if not should_continue:
break
except asyncio.CancelledError:
logger.warning("Agent loop cancelled")
break
except Exception as e:
logger.error(f"Error in agent loop: {e}")
await session.send_event(
Event(event_type="error", data={"error": str(e)})
)
logger.info("Agent loop exited")
finally:
# Emergency save if session saving is enabled and shutdown wasn't called properly
if session.config.save_sessions and session.is_running:
logger.info("Emergency save: preserving session before exit...")
try:
local_path = session.save_and_upload_detached(
session.config.session_dataset_repo
)
if local_path:
logger.info("Emergency save successful, upload in progress")
except Exception as e:
logger.error(f"Emergency save failed: {e}")