Files
nanobot/nanobot/agent/runner.py
T

1476 lines
59 KiB
Python

"""Shared execution loop for tool-using agents."""
from __future__ import annotations
import asyncio
import inspect
import os
from copy import deepcopy
from dataclasses import dataclass, field
from pathlib import Path
from typing import Any, Callable
from loguru import logger
from nanobot.agent.context_governance import (
ContextGovernanceConfig,
ContextGovernor,
)
from nanobot.agent.hook import AgentHook, AgentHookContext, AgentRunHookContext
from nanobot.agent.tools.registry import ToolRegistry, is_tool_error_result
from nanobot.providers.base import LLMProvider, LLMResponse, ToolCallRequest
from nanobot.runtime_context import (
RUNTIME_CONTEXT_MESSAGE_META,
detach_runtime_context,
reattach_runtime_context,
)
from nanobot.session.history_visibility import is_hidden_history_message
from nanobot.utils.helpers import (
IncrementalThinkExtractor,
build_assistant_message,
estimate_message_tokens,
estimate_prompt_tokens_chain,
extract_reasoning,
strip_reasoning_tags,
strip_think,
)
from nanobot.utils.llm_runtime import LLMRuntime
from nanobot.utils.prompt_templates import render_template
from nanobot.utils.runtime import (
EMPTY_FINAL_RESPONSE_MESSAGE,
build_budget_exhausted_finalization_message,
build_finalization_retry_message,
build_goal_continue_message,
build_length_recovery_message,
is_blank_text,
repeated_external_lookup_error,
repeated_workspace_violation_error,
)
GoalContinueMessage = str | Callable[[], str | None]
_DEFAULT_ERROR_MESSAGE = "Sorry, I encountered an error calling the AI model."
_ARREARAGE_ERROR_MESSAGE = (
"The AI provider rejected the request because the API key is out of quota or the "
"account is in arrears. Please top up / check the billing status of your API key and try again."
)
_PERSISTED_MODEL_ERROR_PLACEHOLDER = "[Assistant reply unavailable due to model error.]"
_MAX_EMPTY_RETRIES = 2
_MAX_LENGTH_RECOVERIES = 3
_MAX_INJECTIONS_PER_TURN = 3
_MAX_INJECTION_CYCLES = 5
def _restore_outer_whitespace(content: str, original: str | None) -> str:
"""Restore boundary whitespace stripped while cleaning one recovered segment."""
if not original:
return content
leading_size = len(original) - len(original.lstrip())
trailing_size = len(original) - len(original.rstrip())
leading = original[:leading_size]
trailing = original[-trailing_size:] if trailing_size else ""
return f"{leading}{content}{trailing}"
@dataclass(slots=True)
class AgentRunSpec:
"""Configuration for a single agent execution."""
initial_messages: list[dict[str, Any]]
tools: ToolRegistry
runtime: LLMRuntime
max_iterations: int
max_tool_result_chars: int
hook: AgentHook | None = None
error_message: str | None = _DEFAULT_ERROR_MESSAGE
max_iterations_message: str | None = None
concurrent_tools: bool = False
fail_on_tool_error: bool = False
workspace: Path | None = None
session_key: str | None = None
context_block_limit: int | None = None
provider_retry_mode: str = "standard"
progress_callback: Any | None = None
stream_progress_deltas: bool = True
retry_wait_callback: Any | None = None
checkpoint_callback: Any | None = None
injection_callback: Any | None = None
llm_timeout_s: float | None = None
goal_active_predicate: Callable[[], bool] | None = None
goal_continue_message: GoalContinueMessage | None = None
finalize_on_max_iterations: bool = True
@dataclass(slots=True)
class AgentRunResult:
"""Outcome of a shared agent execution."""
final_content: str | None
messages: list[dict[str, Any]]
tools_used: list[str] = field(default_factory=list)
usage: dict[str, int] = field(default_factory=dict)
stop_reason: str = "completed"
error: str | None = None
tool_events: list[dict[str, str]] = field(default_factory=list)
had_injections: bool = False
class AgentRunner:
"""Run a tool-capable LLM loop without product-layer concerns."""
def __init__(self) -> None:
self.context_governor = ContextGovernor()
@staticmethod
def _merge_message_content(left: Any, right: Any) -> str | list[dict[str, Any]]:
if isinstance(left, str) and isinstance(right, str):
return f"{left}\n\n{right}" if left else right
def _to_blocks(value: Any) -> list[dict[str, Any]]:
if isinstance(value, list):
return [
item if isinstance(item, dict) else {"type": "text", "text": str(item)}
for item in value
]
if value is None:
return []
return [{"type": "text", "text": str(value)}]
return _to_blocks(left) + _to_blocks(right)
@classmethod
def _append_injected_messages(
cls,
messages: list[dict[str, Any]],
injections: list[dict[str, Any]],
) -> None:
"""Append injected user messages while preserving role alternation."""
for injection in injections:
if (
messages
and injection.get("role") == "user"
and messages[-1].get("role") == "user"
and not is_hidden_history_message(injection)
and not is_hidden_history_message(messages[-1])
):
merged = dict(messages[-1])
left_meta = merged.get("_meta")
right_meta = injection.get("_meta")
left_marker = (
left_meta.get(RUNTIME_CONTEXT_MESSAGE_META)
if isinstance(left_meta, dict)
else None
)
right_marker = (
right_meta.get(RUNTIME_CONTEXT_MESSAGE_META)
if isinstance(right_meta, dict)
else None
)
detached_left = (
detach_runtime_context(merged.get("content"), left_marker)
if isinstance(left_marker, dict)
else (merged.get("content"), [], [])
)
detached_right = (
detach_runtime_context(injection.get("content"), right_marker)
if isinstance(right_marker, dict)
else (injection.get("content"), [], [])
)
if detached_left is not None and detached_right is not None:
left_content, left_sources, left_blocks = detached_left
right_content, right_sources, right_blocks = detached_right
merged_content = cls._merge_message_content(left_content, right_content)
context_blocks = [*left_blocks, *right_blocks]
if context_blocks:
merged_content, marker = reattach_runtime_context(
merged_content,
[*left_sources, *right_sources],
context_blocks,
)
internal_meta = dict(left_meta) if isinstance(left_meta, dict) else {}
if isinstance(right_meta, dict):
for key, value in right_meta.items():
internal_meta.setdefault(key, value)
internal_meta[RUNTIME_CONTEXT_MESSAGE_META] = marker
merged["_meta"] = internal_meta
merged["content"] = merged_content
else:
merged["content"] = cls._merge_message_content(
merged.get("content"),
injection.get("content"),
)
messages[-1] = merged
continue
messages.append(injection)
async def _try_drain_injections(
self,
spec: AgentRunSpec,
messages: list[dict[str, Any]],
assistant_message: dict[str, Any] | None,
injection_cycles: int,
*,
phase: str = "after error",
iteration: int | None = None,
allow_goal_continue: bool = False,
) -> tuple[bool, int]:
"""Drain pending injections. Returns (should_continue, updated_cycles).
If injections are found and we haven't exceeded _MAX_INJECTION_CYCLES,
append them to *messages* (and emit a checkpoint if *assistant_message*
and *iteration* are both provided) and return (True, cycles+1) so the
caller continues the iteration loop. Otherwise return (False, cycles).
"""
injections: list[dict[str, Any]] = []
real_injection = False
if injection_cycles < _MAX_INJECTION_CYCLES:
injections = await self._drain_injections(spec)
real_injection = bool(injections)
if not injections and allow_goal_continue and assistant_message is not None:
predicate = spec.goal_active_predicate
if predicate is not None and predicate():
injections = [self._build_goal_continue_message(spec)]
if not injections:
return False, injection_cycles
if real_injection:
injection_cycles += 1
if assistant_message is not None:
messages.append(assistant_message)
if iteration is not None:
await self._emit_checkpoint(
spec,
{
"phase": "final_response",
"iteration": iteration,
"model": spec.runtime.model,
"assistant_message": assistant_message,
"completed_tool_results": [],
"pending_tool_calls": [],
},
)
self._append_injected_messages(messages, injections)
if real_injection:
logger.info(
"Injected {} follow-up message(s) {} ({}/{})",
len(injections), phase, injection_cycles, _MAX_INJECTION_CYCLES,
)
else:
logger.info("Injected sustained-goal continuation {}", phase)
return True, injection_cycles
def _build_goal_continue_message(self, spec: AgentRunSpec) -> dict[str, str]:
custom = spec.goal_continue_message
if callable(custom):
try:
custom = custom()
except Exception:
logger.exception("goal_continue_message callback failed")
custom = None
return build_goal_continue_message(custom)
async def _drain_injections(self, spec: AgentRunSpec) -> list[dict[str, Any]]:
"""Drain pending user messages via the injection callback.
Returns normalized user messages (capped by
``_MAX_INJECTIONS_PER_TURN``), or an empty list when there is
nothing to inject. Messages beyond the cap are logged so they
are not silently lost.
"""
if spec.injection_callback is None:
return []
try:
signature = inspect.signature(spec.injection_callback)
accepts_limit = (
"limit" in signature.parameters
or any(
parameter.kind is inspect.Parameter.VAR_KEYWORD
for parameter in signature.parameters.values()
)
)
if accepts_limit:
items = await spec.injection_callback(limit=_MAX_INJECTIONS_PER_TURN)
else:
items = await spec.injection_callback()
except Exception:
logger.exception("injection_callback failed")
return []
if not items:
return []
injected_messages: list[dict[str, Any]] = []
for item in items:
if item is None:
continue
if isinstance(item, dict) and item.get("role") == "user" and "content" in item:
if self._has_injection_content(item.get("content")):
injected_messages.append(item)
continue
if isinstance(item, dict):
continue
content = getattr(item, "content") if hasattr(item, "content") else str(item)
if self._has_injection_content(content):
injected_messages.append({"role": "user", "content": content})
if len(injected_messages) > _MAX_INJECTIONS_PER_TURN:
dropped = len(injected_messages) - _MAX_INJECTIONS_PER_TURN
logger.warning(
"Injection callback returned {} messages, capping to {} ({} dropped)",
len(injected_messages), _MAX_INJECTIONS_PER_TURN, dropped,
)
injected_messages = injected_messages[:_MAX_INJECTIONS_PER_TURN]
return injected_messages
@staticmethod
def _has_injection_content(content: Any) -> bool:
if content is None:
return False
if isinstance(content, str):
return bool(content.strip())
if isinstance(content, list):
return bool(content)
return True
async def run(self, spec: AgentRunSpec) -> AgentRunResult:
hook = spec.hook or AgentHook()
messages = list(spec.initial_messages)
context = AgentRunHookContext(messages=deepcopy(messages))
try:
await hook.before_run(context)
result = await self._run_core(spec, hook, messages)
except asyncio.CancelledError as exc:
context.messages = deepcopy(messages)
context.stop_reason = "cancelled"
context.error = None
context.exception = exc
raise
except Exception as exc:
context.messages = deepcopy(messages)
context.stop_reason = "error"
context.error = f"Error: {type(exc).__name__}: {exc}"
context.exception = exc
await hook.on_error(context)
raise
else:
context.messages = deepcopy(result.messages)
context.final_content = result.final_content
context.tools_used = list(result.tools_used)
context.usage = dict(result.usage)
context.stop_reason = result.stop_reason
context.error = result.error
context.tool_events = deepcopy(result.tool_events)
context.had_injections = result.had_injections
context.exception = None
if context.error is not None:
await hook.on_error(context)
await hook.after_run(context)
return result
finally:
context.messages = deepcopy(messages)
if context.exception is None:
await hook.on_finally(context)
else:
try:
await hook.on_finally(context)
except Exception:
logger.exception(
"AgentHook.on_finally error after {}",
context.stop_reason or "run exception",
)
async def _run_core(
self,
spec: AgentRunSpec,
hook: AgentHook,
messages: list[dict[str, Any]],
) -> AgentRunResult:
final_content: str | None = None
tools_used: list[str] = []
usage: dict[str, int] = {"prompt_tokens": 0, "completion_tokens": 0}
error: str | None = None
stop_reason = "completed"
tool_events: list[dict[str, str]] = []
external_lookup_counts: dict[str, int] = {}
# Per-turn throttle for repeated attempts against the same outside target.
workspace_violation_counts: dict[str, int] = {}
empty_content_retries = 0
# Segments from one uninterrupted length-recovery chain. Tool work or
# injected user input starts a new logical answer and clears the chain.
length_recovery_parts: list[str] = []
had_injections = False
injection_cycles = 0
compacted_tool_call_ids: set[str] = set()
governance_config = ContextGovernanceConfig(
provider=spec.runtime.provider,
model=spec.runtime.model,
tools=spec.tools,
workspace=spec.workspace,
session_key=spec.session_key,
max_tool_result_chars=spec.max_tool_result_chars,
context_window_tokens=spec.runtime.context_window_tokens,
context_block_limit=spec.context_block_limit,
max_tokens=spec.runtime.generation.max_tokens,
inflight_start_index=len(spec.initial_messages),
)
for iteration in range(spec.max_iterations):
# Keep the persisted conversation untouched. Context governance
# may repair or compact historical messages for the model, but
# those synthetic edits must not shift the append boundary used
# later when the caller saves only the new turn. A governance
# failure must stop the run instead of sending an ungoverned copy.
messages_for_model = self.context_governor.prepare_for_model(
governance_config,
messages,
compacted_tool_call_ids,
)
context = AgentHookContext(
iteration=iteration,
messages=messages,
session_key=spec.session_key,
)
await hook.before_iteration(context)
response = await self._request_model(spec, messages_for_model, hook, context)
context.response = response
context.tool_calls = list(response.tool_calls)
original_content = response.content
reasoning_text, cleaned_content = extract_reasoning(
response.reasoning_content,
response.thinking_blocks,
response.content,
)
response.content = cleaned_content
raw_usage = self._usage_or_estimate(spec, messages_for_model, response)
context.usage = dict(raw_usage)
self._accumulate_usage(usage, raw_usage)
if reasoning_text and not context.streamed_reasoning:
await hook.emit_reasoning(reasoning_text)
await hook.emit_reasoning_end()
context.streamed_reasoning = True
if response.should_execute_tools:
context.tool_calls = list(response.tool_calls)
if hook.wants_streaming():
await hook.on_stream_end(context, resuming=True)
assistant_message = build_assistant_message(
response.content or "",
tool_calls=[tc.to_openai_tool_call() for tc in response.tool_calls],
reasoning_content=response.reasoning_content,
thinking_blocks=response.thinking_blocks,
)
messages.append(assistant_message)
await self._emit_checkpoint(
spec,
{
"phase": "awaiting_tools",
"iteration": iteration,
"model": spec.runtime.model,
"assistant_message": assistant_message,
"completed_tool_results": [],
"pending_tool_calls": [tc.to_openai_tool_call() for tc in response.tool_calls],
},
)
await hook.before_execute_tools(context)
results, new_events, fatal_error = await self._execute_tools(
spec,
response.tool_calls,
external_lookup_counts,
workspace_violation_counts,
hook,
context,
)
tool_events.extend(new_events)
tools_used.extend(
tool_call.name
for tool_call, event in zip(response.tool_calls, new_events)
if event.get("status") == "ok"
)
context.tool_results = list(results)
context.tool_events = list(new_events)
completed_tool_results: list[dict[str, Any]] = []
for tool_call, result in zip(response.tool_calls, results):
tool_message = {
"role": "tool",
"tool_call_id": tool_call.id,
"name": tool_call.name,
"content": self.context_governor.normalize_tool_result(
governance_config,
tool_call.id,
tool_call.name,
result,
),
}
messages.append(tool_message)
completed_tool_results.append(tool_message)
if fatal_error is not None:
error = f"Error: {type(fatal_error).__name__}: {fatal_error}"
final_content = error
stop_reason = "tool_error"
self._append_final_message(messages, final_content)
context.final_content = final_content
context.error = error
context.stop_reason = stop_reason
await hook.after_iteration(context)
should_continue, injection_cycles = await self._try_drain_injections(
spec, messages, None, injection_cycles,
phase="after tool error",
)
if should_continue:
had_injections = True
length_recovery_parts.clear()
continue
break
await self._emit_checkpoint(
spec,
{
"phase": "tools_completed",
"iteration": iteration,
"model": spec.runtime.model,
"assistant_message": assistant_message,
"completed_tool_results": completed_tool_results,
"pending_tool_calls": [],
},
)
empty_content_retries = 0
length_recovery_parts.clear()
# Checkpoint 1: drain injections after tools, before next LLM call
_drained, injection_cycles = await self._try_drain_injections(
spec, messages, None, injection_cycles,
phase="after tool execution",
)
if _drained:
had_injections = True
await hook.after_iteration(context)
continue
if response.has_tool_calls:
logger.warning(
"Ignoring tool calls under finish_reason='{}' for {}",
response.finish_reason,
spec.session_key or "default",
)
clean = hook.finalize_content(context, response.content)
if response.finish_reason != "error" and is_blank_text(clean):
empty_content_retries += 1
if empty_content_retries < _MAX_EMPTY_RETRIES:
logger.warning(
"Empty response on turn {} for {} ({}/{}); retrying",
iteration,
spec.session_key or "default",
empty_content_retries,
_MAX_EMPTY_RETRIES,
)
if hook.wants_streaming():
await hook.on_stream_end(context, resuming=False)
await hook.after_iteration(context)
continue
logger.warning(
"Empty response on turn {} for {} after {} retries; attempting finalization",
iteration,
spec.session_key or "default",
empty_content_retries,
)
if hook.wants_streaming():
await hook.on_stream_end(context, resuming=False)
retry_messages = self._finalization_retry_messages(messages_for_model)
response = await self._request_finalization_retry(spec, messages_for_model)
retry_usage = self._usage_or_estimate(spec, retry_messages, response)
self._accumulate_usage(usage, retry_usage)
raw_usage = self._merge_usage(raw_usage, retry_usage)
context.response = response
context.usage = dict(raw_usage)
context.tool_calls = list(response.tool_calls)
original_content = response.content
clean = hook.finalize_content(context, response.content)
if response.finish_reason == "length" and not is_blank_text(clean):
if len(length_recovery_parts) < _MAX_LENGTH_RECOVERIES:
length_recovery_parts.append(
_restore_outer_whitespace(clean, original_content)
)
logger.info(
"Output truncated on turn {} for {} ({}/{}); continuing",
iteration,
spec.session_key or "default",
len(length_recovery_parts),
_MAX_LENGTH_RECOVERIES,
)
if hook.wants_streaming():
await hook.on_stream_end(context, resuming=True)
messages.append(build_assistant_message(
clean,
reasoning_content=response.reasoning_content,
thinking_blocks=response.thinking_blocks,
))
messages.append(build_length_recovery_message(clean))
await hook.after_iteration(context)
continue
assistant_message: dict[str, Any] | None = None
if response.finish_reason != "error" and not is_blank_text(clean):
assistant_message = build_assistant_message(
clean,
reasoning_content=response.reasoning_content,
thinking_blocks=response.thinking_blocks,
)
# Check for mid-turn injections BEFORE signaling stream end.
# If injections are found we keep the stream alive (resuming=True)
# so streaming channels don't prematurely finalize the card.
should_continue, injection_cycles = await self._try_drain_injections(
spec, messages, assistant_message, injection_cycles,
phase="after final response",
iteration=iteration,
allow_goal_continue=True,
)
if should_continue:
had_injections = True
if hook.wants_streaming():
await hook.on_stream_end(context, resuming=should_continue)
if should_continue:
length_recovery_parts.clear()
await hook.after_iteration(context)
continue
if response.finish_reason == "error":
if LLMProvider.is_arrearage_response(response):
final_content = _ARREARAGE_ERROR_MESSAGE
else:
final_content = clean or spec.error_message or _DEFAULT_ERROR_MESSAGE
stop_reason = "error"
error = final_content
self._append_model_error_placeholder(messages)
context.final_content = final_content
context.error = error
context.stop_reason = stop_reason
await hook.after_iteration(context)
should_continue, injection_cycles = await self._try_drain_injections(
spec, messages, None, injection_cycles,
phase="after LLM error",
)
if should_continue:
had_injections = True
length_recovery_parts.clear()
continue
break
if is_blank_text(clean):
final_content = EMPTY_FINAL_RESPONSE_MESSAGE
stop_reason = "empty_final_response"
error = final_content
self._append_final_message(messages, final_content)
context.final_content = final_content
context.error = error
context.stop_reason = stop_reason
await hook.after_iteration(context)
should_continue, injection_cycles = await self._try_drain_injections(
spec, messages, None, injection_cycles,
phase="after empty response",
)
if should_continue:
had_injections = True
length_recovery_parts.clear()
continue
break
messages.append(assistant_message or build_assistant_message(
clean,
reasoning_content=response.reasoning_content,
thinking_blocks=response.thinking_blocks,
))
await self._emit_checkpoint(
spec,
{
"phase": "final_response",
"iteration": iteration,
"model": spec.runtime.model,
"assistant_message": messages[-1],
"completed_tool_results": [],
"pending_tool_calls": [],
},
)
if length_recovery_parts:
final_content = (
"".join(length_recovery_parts)
+ _restore_outer_whitespace(clean, original_content)
).strip()
else:
final_content = clean
context.final_content = final_content
context.stop_reason = stop_reason
await hook.after_iteration(context)
break
else:
stop_reason = "max_iterations"
# Drain any remaining injections so they are appended to the
# conversation history instead of being re-published as
# independent inbound messages by _dispatch's finally block.
# We include them before the no-tools finalization pass so the
# final response can account for every known follow-up.
drained_after_max_iterations, injection_cycles = await self._try_drain_injections(
spec, messages, None, injection_cycles,
phase="after max_iterations",
)
if drained_after_max_iterations:
had_injections = True
final_content = None
if spec.finalize_on_max_iterations:
final_content = await self._try_finalize_after_max_iterations(
spec,
hook,
messages,
usage,
)
if final_content is None:
final_content = self._max_iterations_fallback(spec)
self._append_final_message(messages, final_content)
return AgentRunResult(
final_content=final_content,
messages=messages,
tools_used=tools_used,
usage=usage,
stop_reason=stop_reason,
error=error,
tool_events=tool_events,
had_injections=had_injections,
)
def _build_request_kwargs(
self,
spec: AgentRunSpec,
messages: list[dict[str, Any]],
*,
tools: list[dict[str, Any]] | None,
) -> dict[str, Any]:
kwargs: dict[str, Any] = {
"messages": messages,
"tools": tools,
"model": spec.runtime.model,
"retry_mode": spec.provider_retry_mode,
"on_retry_wait": spec.retry_wait_callback,
}
generation = spec.runtime.generation
kwargs["temperature"] = generation.temperature
kwargs["max_tokens"] = generation.max_tokens
kwargs["reasoning_effort"] = generation.reasoning_effort
return kwargs
async def _request_model(
self,
spec: AgentRunSpec,
messages: list[dict[str, Any]],
hook: AgentHook,
context: AgentHookContext,
*,
malformed_retry: bool = False,
):
timeout_s: float | None = spec.llm_timeout_s
if timeout_s is None:
# Default to a finite timeout to avoid per-session lock starvation when an LLM
# request hangs indefinitely (e.g. gateway/network stall).
# Set NANOBOT_LLM_TIMEOUT_S=0 to disable.
raw = os.environ.get("NANOBOT_LLM_TIMEOUT_S", "300").strip()
try:
timeout_s = float(raw)
except (TypeError, ValueError):
timeout_s = 300.0
if timeout_s is not None and timeout_s <= 0:
timeout_s = None
kwargs = self._build_request_kwargs(
spec,
messages,
tools=spec.tools.get_definitions(),
)
wants_streaming = hook.wants_streaming()
wants_progress_streaming = (
not wants_streaming
and spec.stream_progress_deltas
and spec.progress_callback is not None
and getattr(spec.runtime.provider, "supports_progress_deltas", False) is True
)
progress_state: dict[str, bool] | None = None
active_hosted_tools: dict[str, dict[str, Any]] = {}
async def _provider_tool_event(event: dict[str, Any]) -> None:
if event.get("kind") != "hosted_tool":
return
await hook.on_provider_tool_event(context, event)
call_id = event.get("call_id")
if not call_id:
return
call_id = str(call_id)
if event.get("phase") == "start":
active_hosted_tools[call_id] = dict(event)
elif event.get("phase") in {"end", "error"}:
active_hosted_tools.pop(call_id, None)
if wants_streaming:
thinking_buf = ""
async def _stream(delta: str) -> None:
if delta:
context.streamed_content = True
await hook.on_stream(context, delta)
async def _thinking(delta: str) -> None:
nonlocal thinking_buf
if not delta:
return
prev_clean = strip_reasoning_tags(thinking_buf)
thinking_buf += delta
new_clean = strip_reasoning_tags(thinking_buf)
incremental = new_clean[len(prev_clean):]
if incremental:
context.streamed_reasoning = True
await hook.emit_reasoning(incremental)
async def _stream_recover() -> None:
await hook.on_stream_end(context, resuming=True)
coro = spec.runtime.provider.chat_stream_with_retry(
**kwargs,
on_content_delta=_stream,
on_thinking_delta=_thinking,
on_tool_call_delta=_provider_tool_event,
on_stream_recover=_stream_recover,
)
elif wants_progress_streaming:
stream_buf = ""
think_extractor = IncrementalThinkExtractor()
progress_state = {"reasoning_open": False}
async def _stream_progress(delta: str) -> None:
nonlocal stream_buf
if not delta:
return
prev_clean = strip_think(stream_buf)
stream_buf += delta
new_clean = strip_think(stream_buf)
incremental = new_clean[len(prev_clean):]
if await think_extractor.feed(stream_buf, hook.emit_reasoning):
context.streamed_reasoning = True
progress_state["reasoning_open"] = True
if incremental:
if progress_state["reasoning_open"]:
await hook.emit_reasoning_end()
progress_state["reasoning_open"] = False
context.streamed_content = True
await spec.progress_callback(incremental)
coro = spec.runtime.provider.chat_stream_with_retry(
**kwargs,
on_content_delta=_stream_progress,
on_tool_call_delta=_provider_tool_event,
)
else:
coro = spec.runtime.provider.chat_with_retry(**kwargs)
# Streaming requests also have provider-level idle timeouts
# (NANOBOT_STREAM_IDLE_TIMEOUT_S), but a stream that keeps producing
# very slow deltas can still run forever. Use a more generous wall-clock
# timeout for streaming while preserving NANOBOT_LLM_TIMEOUT_S=0 as an
# opt-out for all LLM wall-clock timeouts.
is_streaming_request = wants_streaming or wants_progress_streaming
outer_timeout_s = (
max(300.0, timeout_s * 2)
if is_streaming_request and timeout_s is not None
else timeout_s
)
try:
response = (
await coro if outer_timeout_s is None
else await asyncio.wait_for(coro, timeout=outer_timeout_s)
)
except asyncio.TimeoutError:
if outer_timeout_s is None:
response = LLMResponse(
content="Error calling LLM: stream stalled",
finish_reason="error",
error_kind="timeout",
)
else:
response = LLMResponse(
content=f"Error calling LLM: timed out after {outer_timeout_s:g}s",
finish_reason="error",
error_kind="timeout",
)
# chat_stream_with_retry may recover internally, so only fail unfinished
# hosted calls after the provider returns its final error response.
if response.finish_reason == "error":
for event in list(active_hosted_tools.values()):
await _provider_tool_event({
**event,
"phase": "error",
"result": None,
"error": response.content
or "Model request failed before the provider-hosted tool completed.",
})
if progress_state and progress_state.get("reasoning_open"):
await hook.emit_reasoning_end()
dropped, all_dropped, original_finish_reason = (
self._drop_malformed_tool_calls(response)
)
if (
all_dropped
and original_finish_reason in ("tool_calls", "function_call")
and not malformed_retry
):
logger.warning(
"Retrying LLM request after all {} malformed tool call(s) were dropped",
dropped,
)
retry_messages = self._malformed_tool_call_retry_messages(
messages, response.content,
)
return await self._request_model(
spec, retry_messages, hook, context,
malformed_retry=True,
)
if (
all_dropped
and original_finish_reason in ("tool_calls", "function_call")
and malformed_retry
):
logger.warning(
"Malformed tool calls persisted after retry; falling back to no-tools request",
)
fallback_messages = self._malformed_tool_call_retry_messages(
messages, response.content,
)
return await self._request_no_tools(spec, fallback_messages)
return response
@staticmethod
def _drop_malformed_tool_calls(
response: LLMResponse,
) -> tuple[int, bool, str | None]:
"""Strip tool calls whose name is missing/non-string from the response.
Returns (dropped_count, all_dropped, original_finish_reason).
A degenerate call (name=None or "") cannot be executed, and if it were
persisted into the assistant message it would be replayed on every
subsequent turn, causing upstream validation errors
(``tool_use.name: Input should be a valid string``) that permanently
wedge the session. Dropping it here keeps it out of execution, the
assistant message, and the saved history in one place.
"""
calls = getattr(response, "tool_calls", None)
if not calls:
return (0, False, getattr(response, "finish_reason", None))
valid = [tc for tc in calls if tc.has_valid_name()]
if len(valid) == len(calls):
return (0, False, getattr(response, "finish_reason", None))
dropped = len(calls) - len(valid)
original_finish_reason = getattr(response, "finish_reason", None)
logger.warning(
"Dropped {} malformed tool call(s) with missing/non-string name "
"from LLM response (finish_reason={!r})",
dropped,
original_finish_reason,
)
response.tool_calls = valid
if not valid:
response.finish_reason = "stop"
return (dropped, not valid, original_finish_reason)
@staticmethod
def _malformed_tool_call_retry_messages(
messages: list[dict[str, Any]],
assistant_text: str | None,
) -> list[dict[str, Any]]:
retry_messages = list(messages)
note = (
"The previous model response attempted to call tools, but every tool call "
"was malformed: the tool_use blocks had missing or non-string tool names. "
"Do not answer with a promise to use tools. Either call the required tools again "
"using valid tool names from the provided tool list and JSON object inputs, or give "
"a final answer only if no tool is required."
)
if assistant_text:
note += (
f"\n\nPrevious assistant text before the malformed calls:\n"
f"{assistant_text}"
)
retry_messages.append({"role": "user", "content": note})
return retry_messages
async def _request_finalization_retry(
self,
spec: AgentRunSpec,
messages: list[dict[str, Any]],
):
retry_messages = self._finalization_retry_messages(messages)
return await self._request_no_tools(spec, retry_messages)
@staticmethod
def _finalization_retry_messages(messages: list[dict[str, Any]]) -> list[dict[str, Any]]:
retry_messages = list(messages)
retry_messages.append(build_finalization_retry_message())
return retry_messages
async def _try_finalize_after_max_iterations(
self,
spec: AgentRunSpec,
hook: AgentHook,
messages: list[dict[str, Any]],
usage: dict[str, int],
) -> str | None:
retry_messages = self._budget_exhausted_finalization_messages(messages)
try:
response = await self._request_no_tools(spec, retry_messages)
except Exception:
logger.exception(
"Budget-exhausted finalization failed for {}; using fallback",
spec.session_key or "default",
)
return None
raw_usage = self._usage_or_estimate(spec, retry_messages, response)
self._accumulate_usage(usage, raw_usage)
if response.finish_reason == "error" or response.has_tool_calls:
logger.warning(
"Budget-exhausted finalization returned finish_reason='{}' "
"with {} tool call(s) for {}; using fallback",
response.finish_reason,
len(response.tool_calls),
spec.session_key or "default",
)
return None
context = AgentHookContext(
iteration=spec.max_iterations,
messages=messages,
response=response,
usage=dict(raw_usage),
session_key=spec.session_key,
)
clean = hook.finalize_content(context, response.content)
if is_blank_text(clean):
return None
return clean
async def _request_no_tools(
self,
spec: AgentRunSpec,
messages: list[dict[str, Any]],
) -> LLMResponse:
kwargs = self._build_request_kwargs(spec, messages, tools=None)
return await spec.runtime.provider.chat_with_retry(**kwargs)
@staticmethod
def _budget_exhausted_finalization_messages(
messages: list[dict[str, Any]],
) -> list[dict[str, Any]]:
retry_messages = list(messages)
retry_messages.append(build_budget_exhausted_finalization_message())
return retry_messages
@staticmethod
def _max_iterations_fallback(spec: AgentRunSpec) -> str:
if spec.max_iterations_message:
return spec.max_iterations_message.format(
max_iterations=spec.max_iterations,
)
return render_template(
"agent/max_iterations_message.md",
strip=True,
max_iterations=spec.max_iterations,
)
def _usage_or_estimate(
self,
spec: AgentRunSpec,
messages: list[dict[str, Any]],
response: LLMResponse,
) -> dict[str, int]:
usage = self._usage_dict(response.usage)
total = self._usage_total(usage)
if total > 0:
usage["total_tokens"] = total
usage.setdefault("provider_tokens", total)
return usage
if response.finish_reason == "error":
return {}
return self._estimate_response_usage(spec, messages, response)
def _estimate_response_usage(
self,
spec: AgentRunSpec,
messages: list[dict[str, Any]],
response: LLMResponse,
) -> dict[str, int]:
try:
tools = spec.tools.get_definitions()
except Exception:
tools = None
prompt_tokens, _ = estimate_prompt_tokens_chain(
spec.runtime.provider,
spec.runtime.model,
messages,
tools,
)
assistant_message = build_assistant_message(
response.content or "",
tool_calls=[tc.to_openai_tool_call() for tc in response.tool_calls],
reasoning_content=response.reasoning_content,
thinking_blocks=response.thinking_blocks,
)
completion_tokens = estimate_message_tokens(assistant_message)
total_tokens = max(0, prompt_tokens) + max(0, completion_tokens)
if total_tokens <= 0:
return {}
return {
"prompt_tokens": max(0, prompt_tokens),
"completion_tokens": max(0, completion_tokens),
"total_tokens": total_tokens,
"estimated_tokens": total_tokens,
}
@staticmethod
def _usage_dict(usage: dict[str, Any] | None) -> dict[str, int]:
if not usage:
return {}
result: dict[str, int] = {}
for key, value in usage.items():
try:
result[key] = int(value or 0)
except (TypeError, ValueError):
continue
return result
@staticmethod
def _usage_total(usage: dict[str, int]) -> int:
return max(0, usage.get("total_tokens", 0) or (
usage.get("prompt_tokens", 0) + usage.get("completion_tokens", 0)
))
@staticmethod
def _accumulate_usage(target: dict[str, int], addition: dict[str, int]) -> None:
for key, value in addition.items():
target[key] = target.get(key, 0) + value
@staticmethod
def _merge_usage(left: dict[str, int], right: dict[str, int]) -> dict[str, int]:
merged = dict(left)
for key, value in right.items():
merged[key] = merged.get(key, 0) + value
return merged
async def _execute_tools(
self,
spec: AgentRunSpec,
tool_calls: list[ToolCallRequest],
external_lookup_counts: dict[str, int],
workspace_violation_counts: dict[str, int],
hook: AgentHook | None = None,
context: AgentHookContext | None = None,
) -> tuple[list[Any], list[dict[str, str]], BaseException | None]:
hook = hook or AgentHook()
context = context or AgentHookContext(iteration=0, messages=[])
batches = self._partition_tool_batches(spec, tool_calls)
tool_results: list[tuple[Any, dict[str, str], BaseException | None]] = []
for batch in batches:
if spec.concurrent_tools and len(batch) > 1:
batch_results = await asyncio.gather(*(
self._run_tool(
spec,
tool_call,
external_lookup_counts,
workspace_violation_counts,
hook,
context,
)
for tool_call in batch
))
tool_results.extend(batch_results)
else:
batch_results = []
for tool_call in batch:
result = await self._run_tool(
spec,
tool_call,
external_lookup_counts,
workspace_violation_counts,
hook,
context,
)
tool_results.append(result)
batch_results.append(result)
results: list[Any] = []
events: list[dict[str, str]] = []
fatal_error: BaseException | None = None
for result, event, error in tool_results:
results.append(result)
events.append(event)
if error is not None and fatal_error is None:
fatal_error = error
return results, events, fatal_error
async def _run_tool(
self,
spec: AgentRunSpec,
tool_call: ToolCallRequest,
external_lookup_counts: dict[str, int],
workspace_violation_counts: dict[str, int],
hook: AgentHook | None = None,
context: AgentHookContext | None = None,
) -> tuple[Any, dict[str, str], BaseException | None]:
hook = hook or AgentHook()
context = context or AgentHookContext(iteration=0, messages=[])
hint = "\n\n[Analyze the error above and try a different approach.]"
lookup_error = repeated_external_lookup_error(
tool_call.name,
tool_call.arguments,
external_lookup_counts,
)
if lookup_error:
event = {
"name": tool_call.name,
"status": "error",
"detail": "repeated external lookup blocked",
}
if spec.fail_on_tool_error:
return lookup_error + hint, event, RuntimeError(lookup_error)
return lookup_error + hint, event, None
prepare_call = getattr(spec.tools, "prepare_call", None)
tool, params, prep_error = None, tool_call.arguments, None
if callable(prepare_call):
prepared = prepare_call(tool_call.name, tool_call.arguments)
if isinstance(prepared, tuple) and len(prepared) == 3:
tool, params, prep_error = prepared
if prep_error:
event = {
"name": tool_call.name,
"status": "error",
"detail": prep_error.split(": ", 1)[-1][:120],
}
handled = self._classify_violation(
raw_text=prep_error,
soft_payload=prep_error + hint,
event=event,
tool_call=tool_call,
workspace_violation_counts=workspace_violation_counts,
)
if handled is not None:
return handled
return prep_error + hint, event, (
RuntimeError(prep_error) if spec.fail_on_tool_error else None
)
await hook.before_execute_tool(context, tool_call, tool, params)
try:
if tool is not None:
result = await tool.execute(**params)
else:
result = await spec.tools.execute(tool_call.name, params)
except asyncio.CancelledError:
raise
except Exception as exc:
await hook.on_execute_tool_error(context, tool_call, tool, params, exc)
event = {
"name": tool_call.name,
"status": "error",
"detail": str(exc),
}
payload = f"Error: {type(exc).__name__}: {exc}"
handled = self._classify_violation(
raw_text=str(exc),
# Preserve legacy exception payloads without the retry hint.
soft_payload=payload,
event=event,
tool_call=tool_call,
workspace_violation_counts=workspace_violation_counts,
)
if handled is not None:
return handled
if spec.fail_on_tool_error:
return payload, event, exc
return payload, event, None
if is_tool_error_result(tool_call.name, result):
await hook.on_execute_tool_error(context, tool_call, tool, params, result)
event = {
"name": tool_call.name,
"status": "error",
"detail": result.replace("\n", " ").strip()[:120],
}
handled = self._classify_violation(
raw_text=result,
soft_payload=result + hint,
event=event,
tool_call=tool_call,
workspace_violation_counts=workspace_violation_counts,
)
if handled is not None:
return handled
if spec.fail_on_tool_error:
return result + hint, event, RuntimeError(result)
return result + hint, event, None
await hook.after_execute_tool(context, tool_call, tool, params, result)
detail = "" if result is None else str(result)
detail = detail.replace("\n", " ").strip()
if not detail:
detail = "(empty)"
elif len(detail) > 120:
detail = detail[:120] + "..."
return result, {"name": tool_call.name, "status": "ok", "detail": detail}, None
# SSRF is a hard security block at the tool boundary, but the agent turn
# should recover conversationally instead of aborting the runtime.
_SSRF_MARKERS: tuple[str, ...] = (
"internal/private url detected",
"private/internal address",
"private address",
)
_SSRF_BOUNDARY_NOTE: str = (
"This is a non-bypassable security boundary. Stop trying to access "
"private/internal URLs. Do not retry with curl, wget, encoded IPs, "
"alternate DNS, redirects, proxies, or another tool. Ask the user for "
"local files, logs, screenshots, or an explicit safe public URL instead. "
"If the user explicitly trusts this private URL, ask them to whitelist "
"the exact IP/CIDR via tools.ssrfWhitelist."
)
# Non-SSRF boundary markers returned to the LLM as recoverable tool errors.
_WORKSPACE_VIOLATION_MARKERS: tuple[str, ...] = (
"outside the configured workspace",
"outside allowed directory",
"working_dir is outside",
"working_dir could not be resolved",
"path outside working dir",
"path traversal detected",
)
@classmethod
def _is_ssrf_violation(cls, text: str) -> bool:
if not text:
return False
lowered = text.lower()
return any(marker in lowered for marker in cls._SSRF_MARKERS)
@classmethod
def _is_workspace_violation(cls, text: str) -> bool:
"""True when *text* looks like any policy boundary rejection."""
if not text:
return False
lowered = text.lower()
if cls._is_ssrf_violation(lowered):
return True
return any(marker in lowered for marker in cls._WORKSPACE_VIOLATION_MARKERS)
def _classify_violation(
self,
*,
raw_text: str,
soft_payload: str,
event: dict[str, str],
tool_call: ToolCallRequest,
workspace_violation_counts: dict[str, int],
) -> tuple[Any, dict[str, str], BaseException | None] | None:
"""Classify safety-boundary failures, or return ``None`` to pass through."""
if self._is_ssrf_violation(raw_text):
logger.warning(
"Tool {} blocked by SSRF guard; returning non-retryable tool error: {}",
tool_call.name,
raw_text.replace("\n", " ").strip()[:200],
)
event["detail"] = self._event_detail("ssrf_violation: ", raw_text)
return self._ssrf_soft_payload(raw_text), event, None
if self._is_workspace_violation(raw_text):
escalation = repeated_workspace_violation_error(
tool_call.name,
tool_call.arguments,
workspace_violation_counts,
)
event["detail"] = self._event_detail("workspace_violation: ", raw_text)
if escalation is not None:
logger.warning(
"Tool {} hit workspace boundary repeatedly; escalating hint",
tool_call.name,
)
event["detail"] = self._event_detail(
"workspace_violation_escalated: ",
raw_text,
)
return escalation, event, None
return soft_payload, event, None
return None
@classmethod
def _ssrf_soft_payload(cls, raw_text: str) -> str:
text = raw_text.strip() or "Error: request blocked by SSRF guard"
return f"{text}\n\n{cls._SSRF_BOUNDARY_NOTE}"
@staticmethod
def _event_detail(prefix: str, text: str, limit: int = 160) -> str:
return (prefix + text.replace("\n", " ").strip())[:limit]
async def _emit_checkpoint(
self,
spec: AgentRunSpec,
payload: dict[str, Any],
) -> None:
callback = spec.checkpoint_callback
if callback is not None:
await callback(payload)
@staticmethod
def _append_final_message(messages: list[dict[str, Any]], content: str | None) -> None:
if not content:
return
if (
messages
and messages[-1].get("role") == "assistant"
and not messages[-1].get("tool_calls")
):
if messages[-1].get("content") == content:
return
messages[-1] = build_assistant_message(content)
return
messages.append(build_assistant_message(content))
@staticmethod
def _append_model_error_placeholder(messages: list[dict[str, Any]]) -> None:
if messages and messages[-1].get("role") == "assistant" and not messages[-1].get("tool_calls"):
return
messages.append(build_assistant_message(_PERSISTED_MODEL_ERROR_PLACEHOLDER))
def _partition_tool_batches(
self,
spec: AgentRunSpec,
tool_calls: list[ToolCallRequest],
) -> list[list[ToolCallRequest]]:
if not spec.concurrent_tools:
return [[tool_call] for tool_call in tool_calls]
batches: list[list[ToolCallRequest]] = []
current: list[ToolCallRequest] = []
for tool_call in tool_calls:
get_tool = getattr(spec.tools, "get", None)
tool = get_tool(tool_call.name) if callable(get_tool) else None
can_batch = bool(tool and tool.concurrency_safe)
if can_batch:
current.append(tool_call)
continue
if current:
batches.append(current)
current = []
batches.append([tool_call])
if current:
batches.append(current)
return batches