This article is published in English.
Practical notes: Agentic Architectures — Article 13: Human-in-the-Loop Patterns
Operable walkthrough of Practical notes: Agentic Architectures — Article 13: Human-in-the-Loop Patterns: contracts, checks, and drop-in code slots for teams shipping this pattern.
The following notes reconstruct a practical path around “Agentic Architectures — Article 13: Human-in-the-Loop Patterns”. Emphasis stays on contracts, checks, and drop-in code placeholders rather than motivational framing. When working through the Overview stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.
What You’ll Find Here
The What You ll Find stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments. Keep graph state flat and typed. Nested blobs hide which node wrote which field and break resume after interrupts.
Where to Draw the Line
The Where to Draw the stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph. Keep graph state flat and typed. Nested blobs hide which node wrote which field and break resume after interrupts.
+--------------------+------------------------+------------------------+
| | Low Error Cost | High Error Cost |
+--------------------+------------------------+------------------------+
| Reversible | AUTONOMOUS | OVERSIGHT SAMPLING |
| | (agent acts freely) | (act, log, review some)|
+--------------------+------------------------+------------------------+
| Irreversible | APPROVAL FOR NOVEL | APPROVAL GATE |
| | (approve first time, | (always require human |
| | then autonomous) | approval before act) |
+--------------------+------------------------+------------------------+
# harness/hitl/action_policy.py
from enum import Enum
from dataclasses import dataclass
from typing import Optional, Callable
class ApprovalPolicy(Enum):
AUTONOMOUS = "autonomous" # act freely
OVERSIGHT_SAMPLING = "sampling" # act, log, review a sample
APPROVAL_FOR_NOVEL = "approval_novel" # approve first occurrence, then auto
APPROVAL_GATE = "approval_gate" # always require approval
DUAL_APPROVAL = "dual_approval" # require two approvers
@dataclass
class ActionPolicy:
action_name: str
policy: ApprovalPolicy
reason: str
approver_role: Optional[str] = None # required role to approve
timeout_seconds: int = 3600
timeout_action: str = "reject" # "reject" | "escalate" | "proceed"
# Example policy configuration for a customer support agent
SUPPORT_AGENT_POLICIES = {
"read_customer_record": ActionPolicy(
action_name="read_customer_record",
policy=ApprovalPolicy.AUTONOMOUS,
reason="Read-only, reversible, low risk",
),
"draft_response": ActionPolicy(
action_name="draft_response",
policy=ApprovalPolicy.OVERSIGHT_SAMPLING,
reason="Reversible but customer-facing quality matters",
),
"send_customer_email": ActionPolicy(
action_name="send_customer_email",
policy=ApprovalPolicy.APPROVAL_GATE,
reason="Irreversible, customer-facing, reputation risk",
approver_role="support_agent",
timeout_seconds=1800,
timeout_action="reject",
),
"issue_refund": ActionPolicy(
action_name="issue_refund",
policy=ApprovalPolicy.DUAL_APPROVAL,
reason="Financial impact, irreversible",
approver_role="support_manager",
timeout_seconds=7200,
timeout_action="escalate",
),
"delete_account": ActionPolicy(
action_name="delete_account",
policy=ApprovalPolicy.DUAL_APPROVAL,
reason="Catastrophic and irreversible",
approver_role="senior_manager",
timeout_seconds=86400,
timeout_action="reject",
),
}
class ActionPolicyEngine:
"""
Determines whether an action requires human approval and how.
Consulted at the tool execution layer before any action runs.
"""
def __init__(self, policies: dict):
self.policies = policies
def get_policy(self, action_name: str) -> ActionPolicy:
return self.policies.get(
action_name,
# Default to approval gate for unknown actions: fail safe
ActionPolicy(
action_name=action_name,
policy=ApprovalPolicy.APPROVAL_GATE,
reason="Unknown action, defaulting to approval required",
)
)
def requires_approval(self, action_name: str, is_novel: bool = False) -> bool:
policy = self.get_policy(action_name)
if policy.policy == ApprovalPolicy.AUTONOMOUS:
return False
if policy.policy == ApprovalPolicy.OVERSIGHT_SAMPLING:
return False # acts first, reviewed after
if policy.policy == ApprovalPolicy.APPROVAL_FOR_NOVEL:
return is_novel
return True # APPROVAL_GATE and DUAL_APPROVAL always require approval
Pattern 1: Approval Gates
The Pattern 1 Approval Gates stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Document the happy path and the recovery path together. Retries, human gates, and dead-letter handling are part of the product, not later polish. Keep graph state flat and typed. Nested blobs hide which node wrote which field and break resume after interrupts. The Pattern 1 Approval Gates stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.
# harness/hitl/approval_gate.py
import boto3
import time
import uuid
import json
from typing import Optional, Literal
from dataclasses import dataclass
from langgraph.types import interrupt, Command
@dataclass
class ApprovalRequest:
request_id: str
run_id: str
action_name: str
action_args: dict
context_summary: str
requested_at: float
approver_role: str
status: str # PENDING | APPROVED | REJECTED | TIMEOUT
decided_by: Optional[str] = None
decided_at: Optional[float] = None
decision_note: Optional[str] = None
class ApprovalGateManager:
"""
Manages approval requests using LangGraph interrupts for pause/resume
and DynamoDB for durable request state.
"""
def __init__(
self,
table_name: str = "agent-approval-requests",
region: str = "us-east-1",
):
dynamodb = boto3.resource("dynamodb", region_name=region)
self.table = dynamodb.Table(table_name)
self.sns = boto3.client("sns", region_name=region)
def create_approval_request(
self,
run_id: str,
action_name: str,
action_args: dict,
context_summary: str,
approver_role: str,
notification_topic_arn: Optional[str] = None,
) -> ApprovalRequest:
"""
Creates a pending approval request and notifies approvers.
"""
request = ApprovalRequest(
request_id=str(uuid.uuid4()),
run_id=run_id,
action_name=action_name,
action_args=action_args,
context_summary=context_summary,
requested_at=time.time(),
approver_role=approver_role,
status="PENDING",
)
self.table.put_item(Item={
"request_id": request.request_id,
"run_id": request.run_id,
"action_name": request.action_name,
"action_args": json.dumps(request.action_args),
"context_summary": request.context_summary,
"requested_at": int(request.requested_at),
"approver_role": request.approver_role,
"status": "PENDING",
})
# Notify approvers
if notification_topic_arn:
self.sns.publish(
TopicArn=notification_topic_arn,
Subject=f"Approval needed: {action_name}",
Message=json.dumps({
"request_id": request.request_id,
"action": action_name,
"context": context_summary,
"approver_role": approver_role,
}),
)
return request
def record_decision(
self,
request_id: str,
decision: Literal["APPROVED", "REJECTED"],
decided_by: str,
decision_note: Optional[str] = None,
) -> bool:
"""
Records a human's approval decision.
Called by the approval interface when a human responds.
"""
self.table.update_item(
Key={"request_id": request_id},
UpdateExpression=(
"SET #s = :status, decided_by = :by, "
"decided_at = :at, decision_note = :note"
),
ExpressionAttributeNames={"#s": "status"},
ExpressionAttributeValues={
":status": decision,
":by": decided_by,
":at": int(time.time()),
":note": decision_note or "",
},
# Only allow decision on PENDING requests: prevents double-decision
ConditionExpression="#s = :pending",
ExpressionAttributeValues2={":pending": "PENDING"} if False else None,
)
return True
def get_decision(self, request_id: str) -> Optional[str]:
"""Polls the current decision status for a request."""
response = self.table.get_item(Key={"request_id": request_id})
item = response.get("Item")
return item.get("status") if item else None
# The LangGraph node that implements the approval gate
def approval_gate_node(state: dict) -> dict:
"""
A LangGraph node that pauses execution and waits for human approval.
Uses interrupt() to suspend the graph. The graph state is persisted
and can be resumed when the approval decision arrives.
"""
pending_action = state.get("pending_action")
if not pending_action:
return state
# interrupt() pauses the graph and surfaces this data to the caller.
# The caller (your application) presents it to a human and resumes
# the graph with the decision.
decision = interrupt({
"type": "approval_required",
"action": pending_action["name"],
"args": pending_action["args"],
"context": state.get("context_summary", ""),
"run_id": state.get("agent_run_id"),
})
# When resumed, decision contains the human's response
if decision.get("approved"):
return {
**state,
"action_approved": True,
"approved_by": decision.get("approver"),
}
else:
return {
**state,
"action_approved": False,
"rejection_reason": decision.get("reason", "Rejected by human reviewer"),
}
Pattern 2: Escalation
For the Pattern 2 Escalation stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments. Put human approval on edges that spend money or change production data. Compile-time wiring does not equal business completeness.
# harness/hitl/escalation.py
import boto3
import time
import json
from typing import Optional
from dataclasses import dataclass
from langchain_aws import ChatBedrock
from langchain_core.messages import SystemMessage, HumanMessage
ESCALATION_TRIGGERS = {
"low_confidence": "Agent confidence in its solution is below threshold",
"conflicting_information": "Retrieved information contradicts itself",
"policy_ambiguity": "The correct action is genuinely ambiguous under policy",
"high_stakes_uncertainty": "High-stakes decision with insufficient certainty",
"repeated_failure": "Agent has failed the same task multiple times",
"explicit_user_request": "User asked to speak with a human",
}
@dataclass
class EscalationEvent:
escalation_id: str
run_id: str
trigger: str
agent_context: str
agent_attempted_solution: Optional[str]
confidence: float
escalated_at: float
assigned_to: Optional[str] = None
resolution: Optional[str] = None
class EscalationManager:
"""
Handles cases where the agent should hand off to a human.
Distinct from approval gates: escalation is triggered by the agent
recognizing its own limitations.
"""
def __init__(
self,
table_name: str = "agent-escalations",
region: str = "us-east-1",
):
dynamodb = boto3.resource("dynamodb", region_name=region)
self.table = dynamodb.Table(table_name)
bedrock = boto3.client("bedrock-runtime", region_name=region)
self.confidence_model = ChatBedrock(
client=bedrock,
model_id="anthropic.claude-haiku-4-5",
model_kwargs={"temperature": 0, "max_tokens": 256},
)
def should_escalate(
self,
task: str,
proposed_solution: str,
attempts: int,
) -> tuple:
"""
Assesses whether the agent should escalate to a human.
Returns (should_escalate, trigger, confidence).
"""
# Repeated failure is a deterministic trigger
if attempts >= 3:
return True, "repeated_failure", 0.0
# Ask the model to self-assess confidence
response = self.confidence_model.invoke([
SystemMessage(content="""
Assess your confidence in a proposed solution. Be honest about uncertainty.
Consider: Is the information sufficient? Is the answer unambiguous?
Are there conflicting considerations? Is this high-stakes?
Return JSON:
{
"confidence": 0.0 to 1.0,
"should_escalate": true | false,
"trigger": "low_confidence | conflicting_information | policy_ambiguity | high_stakes_uncertainty | none"
}
"""),
HumanMessage(content=f"Task: {task}\n\nProposed solution: {proposed_solution}")
])
try:
assessment = json.loads(response.content)
return (
assessment.get("should_escalate", False),
assessment.get("trigger", "low_confidence"),
assessment.get("confidence", 0.5),
)
except json.JSONDecodeError:
# If we cannot assess confidence, escalate to be safe
return True, "low_confidence", 0.0
def create_escalation(
self,
run_id: str,
trigger: str,
agent_context: str,
attempted_solution: Optional[str],
confidence: float,
notification_topic_arn: Optional[str] = None,
) -> EscalationEvent:
import uuid
event = EscalationEvent(
escalation_id=str(uuid.uuid4()),
run_id=run_id,
trigger=trigger,
agent_context=agent_context,
agent_attempted_solution=attempted_solution,
confidence=confidence,
escalated_at=time.time(),
)
self.table.put_item(Item={
"escalation_id": event.escalation_id,
"run_id": event.run_id,
"trigger": event.trigger,
"agent_context": event.agent_context[:2000],
"attempted_solution": (attempted_solution or "")[:2000],
"confidence": str(confidence),
"escalated_at": int(event.escalated_at),
"status": "OPEN",
})
if notification_topic_arn:
boto3.client("sns").publish(
TopicArn=notification_topic_arn,
Subject=f"Agent escalation: {trigger}",
Message=event.agent_context[:1000],
)
return event
Pattern 3: Collaborative Editing
For the Pattern 3 Collaborative Editing stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph. Put human approval on edges that spend money or change production data. Compile-time wiring does not equal business completeness.
# harness/hitl/collaborative.py
import boto3
import time
import json
from typing import Optional
from dataclasses import dataclass
@dataclass
class CollaborativeEdit:
edit_id: str
run_id: str
original_draft: str
human_edited: str
edit_distance: float # how much was changed
edit_categories: list # "tone", "factual", "structure", "detail"
edited_by: str
edited_at: float
class CollaborativeEditManager:
"""
Manages the draft-edit-finalize flow where a human refines agent output.
Captures edits as learning signals for future improvement.
"""
def __init__(
self,
table_name: str = "agent-collaborative-edits",
region: str = "us-east-1",
):
dynamodb = boto3.resource("dynamodb", region_name=region)
self.table = dynamodb.Table(table_name)
def record_edit(
self,
run_id: str,
original_draft: str,
human_edited: str,
edited_by: str,
edit_categories: list = None,
) -> CollaborativeEdit:
"""
Records a human edit to agent output.
The edit distance and categories become learning signals.
"""
import uuid
edit_distance = self._compute_edit_distance(original_draft, human_edited)
edit = CollaborativeEdit(
edit_id=str(uuid.uuid4()),
run_id=run_id,
original_draft=original_draft,
human_edited=human_edited,
edit_distance=edit_distance,
edit_categories=edit_categories or [],
edited_by=edited_by,
edited_at=time.time(),
)
self.table.put_item(Item={
"edit_id": edit.edit_id,
"run_id": edit.run_id,
"original_draft": original_draft[:5000],
"human_edited": human_edited[:5000],
"edit_distance": str(edit_distance),
"edit_categories": edit.edit_categories,
"edited_by": edited_by,
"edited_at": int(edit.edited_at),
})
return edit
def analyze_edit_patterns(
self,
run_ids: list = None,
min_edits: int = 20,
) -> dict:
"""
Analyzes accumulated edits to find systematic patterns.
If humans consistently edit for the same reason, the agent's
system prompt or procedure should be updated.
"""
response = self.table.scan(Limit=200)
edits = response.get("Items", [])
if len(edits) < min_edits:
return {"sufficient_data": False, "edit_count": len(edits)}
# Aggregate edit categories
category_counts = {}
total_distance = 0.0
for edit in edits:
for cat in edit.get("edit_categories", []):
category_counts[cat] = category_counts.get(cat, 0) + 1
total_distance += float(edit.get("edit_distance", 0))
avg_distance = total_distance / len(edits)
dominant_category = max(category_counts, key=category_counts.get) if category_counts else None
return {
"sufficient_data": True,
"edit_count": len(edits),
"average_edit_distance": round(avg_distance, 3),
"category_distribution": category_counts,
"dominant_edit_category": dominant_category,
"recommendation": self._recommendation(dominant_category, avg_distance),
}
def _recommendation(self, dominant_category: Optional[str], avg_distance: float) -> str:
if avg_distance < 0.1:
return "Edits are minor. Agent output quality is high."
if dominant_category == "tone":
return "Humans frequently adjust tone. Update system prompt with tone guidance."
if dominant_category == "factual":
return "Humans frequently correct facts. Review agent's information sources."
if dominant_category == "structure":
return "Humans frequently restructure. Add output format guidance to system prompt."
return "Review edit patterns manually for systematic improvements."
def _compute_edit_distance(self, a: str, b: str) -> float:
"""Normalized Levenshtein distance, 0 (identical) to 1 (completely different)."""
if not a and not b:
return 0.0
# Simple word-level distance for efficiency on long text
a_words, b_words = a.split(), b.split()
max_len = max(len(a_words), len(b_words))
if max_len == 0:
return 0.0
# Count matching words in order (simplified)
common = len(set(a_words) & set(b_words))
return 1.0 - (common / max_len)
Pattern 4: Oversight Sampling
For the Pattern 4 Oversight Sampling stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Document the happy path and the recovery path together. Retries, human gates, and dead-letter handling are part of the product, not later polish. Put human approval on edges that spend money or change production data. Compile-time wiring does not equal business completeness. For the Pattern 4 Oversight Sampling stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.
# harness/hitl/oversight_sampling.py
import boto3
import random
import time
import json
from typing import Optional
class OversightSampler:
"""
Routes a sample of autonomous actions to human review after execution.
Does not block the action. Catches quality drift and systematic errors.
Feeds into the Article 8 evaluation pipeline.
"""
def __init__(
self,
base_sample_rate: float = 0.05,
table_name: str = "agent-oversight-samples",
region: str = "us-east-1",
):
self.base_sample_rate = base_sample_rate
dynamodb = boto3.resource("dynamodb", region_name=region)
self.table = dynamodb.Table(table_name)
def should_sample(
self,
action_name: str,
agent_confidence: float = 1.0,
is_novel: bool = False,
) -> bool:
"""
Decides whether this action should be sampled for review.
Samples more aggressively for low-confidence and novel actions.
"""
rate = self.base_sample_rate
# Increase sampling for low confidence
if agent_confidence < 0.7:
rate = min(rate * 3, 1.0)
# Always sample novel actions
if is_novel:
return True
return random.random() < rate
def record_for_review(
self,
run_id: str,
action_name: str,
action_args: dict,
action_result: str,
agent_confidence: float,
):
"""Queues an executed action for human review."""
import uuid
self.table.put_item(Item={
"sample_id": str(uuid.uuid4()),
"run_id": run_id,
"action_name": action_name,
"action_args": json.dumps(action_args)[:2000],
"action_result": action_result[:2000],
"agent_confidence": str(agent_confidence),
"sampled_at": int(time.time()),
"review_status": "PENDING",
})
def record_review_outcome(
self,
sample_id: str,
was_correct: bool,
reviewer: str,
notes: Optional[str] = None,
):
"""
Records the human's assessment of a sampled action.
A pattern of incorrect actions should trigger a policy review.
"""
self.table.update_item(
Key={"sample_id": sample_id},
UpdateExpression=(
"SET review_status = :s, was_correct = :c, "
"reviewed_by = :r, review_notes = :n, reviewed_at = :at"
),
ExpressionAttributeValues={
":s": "REVIEWED",
":c": was_correct,
":r": reviewer,
":n": notes or "",
":at": int(time.time()),
}
)
def get_error_rate(self, action_name: str, days: int = 7) -> dict:
"""
Computes the error rate for a sampled action over a window.
If this exceeds threshold, the action's policy should be tightened.
"""
cutoff = int(time.time()) - (days * 86400)
response = self.table.scan(
FilterExpression="action_name = :a AND sampled_at > :c AND review_status = :s",
ExpressionAttributeValues={
":a": action_name,
":c": cutoff,
":s": "REVIEWED",
}
)
reviews = response.get("Items", [])
if not reviews:
return {"sufficient_data": False}
incorrect = sum(1 for r in reviews if not r.get("was_correct", True))
error_rate = incorrect / len(reviews)
return {
"sufficient_data": len(reviews) >= 10,
"sample_size": len(reviews),
"error_rate": round(error_rate, 3),
"recommendation": (
"TIGHTEN_POLICY" if error_rate > 0.1 else "MAINTAIN"
),
}
Timeout and Fallback Handling
When working through the Timeout and Fallback Handling stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments. Checkpoint after expensive steps. Resume should not re-bill the same LLM call when an operator retries a later node.
# harness/hitl/timeout_handler.py
import boto3
import time
from typing import Literal
class ApprovalTimeoutHandler:
"""
Handles approval requests that exceed their timeout.
The timeout action is policy-defined per action type.
Runs as a scheduled Lambda, checking for expired pending requests.
"""
def __init__(
self,
approval_table: str = "agent-approval-requests",
region: str = "us-east-1",
):
dynamodb = boto3.resource("dynamodb", region_name=region)
self.table = dynamodb.Table(approval_table)
self.sns = boto3.client("sns", region_name=region)
def process_expired_requests(self, policies: dict) -> dict:
"""
Scans for pending requests past their timeout and applies
the policy-defined timeout action.
"""
now = int(time.time())
response = self.table.scan(
FilterExpression="#s = :pending",
ExpressionAttributeNames={"#s": "status"},
ExpressionAttributeValues={":pending": "PENDING"},
)
results = {"rejected": 0, "escalated": 0, "proceeded": 0}
for item in response.get("Items", []):
requested_at = int(item.get("requested_at", now))
action_name = item.get("action_name", "")
policy = policies.get(action_name)
if not policy:
continue
age = now - requested_at
if age < policy.timeout_seconds:
continue # not expired yet
timeout_action = policy.timeout_action
if timeout_action == "reject":
self._apply_timeout(item["request_id"], "REJECTED",
"Timed out without approval")
results["rejected"] += 1
elif timeout_action == "escalate":
self._escalate_expired(item)
results["escalated"] += 1
elif timeout_action == "proceed":
# Only for low-risk actions where the gate is advisory
self._apply_timeout(item["request_id"], "APPROVED",
"Auto-approved after timeout per policy")
results["proceeded"] += 1
return results
def _apply_timeout(self, request_id: str, status: str, note: str):
self.table.update_item(
Key={"request_id": request_id},
UpdateExpression="SET #s = :status, decision_note = :note, decided_at = :at",
ExpressionAttributeNames={"#s": "status"},
ExpressionAttributeValues={
":status": status,
":note": note,
":at": int(time.time()),
}
)
def _escalate_expired(self, item: dict):
# Notify a higher tier and extend the deadline
self.table.update_item(
Key={"request_id": item["request_id"]},
UpdateExpression="SET escalated = :t, escalated_at = :at",
ExpressionAttributeValues={":t": True, ":at": int(time.time())},
)
Audit Trail
When working through the Audit Trail stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph. Checkpoint after expensive steps. Resume should not re-bill the same LLM call when an operator retries a later node.
# harness/hitl/audit.py
import boto3
import time
import json
import hashlib
from typing import Optional
class HITLAuditLog:
"""
Immutable audit trail for all human-in-the-loop decisions.
Uses a hash chain so tampering is detectable.
Writes to DynamoDB with a separate append-only access pattern.
"""
def __init__(
self,
table_name: str = "agent-hitl-audit",
region: str = "us-east-1",
):
dynamodb = boto3.resource("dynamodb", region_name=region)
self.table = dynamodb.Table(table_name)
def record_decision(
self,
run_id: str,
decision_type: str, # "approval" | "rejection" | "escalation" | "edit"
action_name: str,
decided_by: str,
decision_details: dict,
previous_hash: Optional[str] = None,
) -> str:
"""
Records a decision in the audit log with a hash chain.
Returns the hash of this entry for chaining the next one.
"""
timestamp = int(time.time())
entry = {
"run_id": run_id,
"decision_type": decision_type,
"action_name": action_name,
"decided_by": decided_by,
"decision_details": json.dumps(decision_details),
"timestamp": timestamp,
"previous_hash": previous_hash or "genesis",
}
# Compute hash of this entry chained to the previous
entry_content = json.dumps(entry, sort_keys=True)
entry_hash = hashlib.sha256(entry_content.encode()).hexdigest()
self.table.put_item(Item={
"audit_id": f"{run_id}#{timestamp}#{entry_hash[:8]}",
**entry,
"entry_hash": entry_hash,
})
return entry_hash
def verify_chain(self, run_id: str) -> bool:
"""
Verifies the hash chain for a run's audit entries.
Returns True if the chain is intact, False if tampering is detected.
"""
response = self.table.query(
KeyConditionExpression="run_id = :rid",
ExpressionAttributeValues={":rid": run_id},
ScanIndexForward=True,
)
entries = sorted(response.get("Items", []), key=lambda x: x["timestamp"])
previous_hash = "genesis"
for entry in entries:
if entry.get("previous_hash") != previous_hash:
return False
# Recompute and verify
check_entry = {
k: entry[k] for k in
["run_id", "decision_type", "action_name", "decided_by",
"decision_details", "timestamp", "previous_hash"]
}
recomputed = hashlib.sha256(
json.dumps(check_entry, sort_keys=True).encode()
).hexdigest()
if recomputed != entry.get("entry_hash"):
return False
previous_hash = entry["entry_hash"]
return True
Production Reality Check
When working through the Production Reality Check stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Document the happy path and the recovery path together. Retries, human gates, and dead-letter handling are part of the product, not later polish. Checkpoint after expensive steps. Resume should not re-bill the same LLM call when an operator retries a later node. When working through the Production Reality Check stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.
Reference Architecture
The Reference Architecture stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments. Keep graph state flat and typed. Nested blobs hide which node wrote which field and break resume after interrupts.
Agent reaches an action
|
v
+---------------------------+
| ActionPolicyEngine |
| Look up action policy |
+---------------------------+
|
+-----+-----+-----------+-----------+
| | | | |
v v v v v
AUTONO SAMP APPROVAL APPROVAL DUAL
MOUS LING FOR NOVEL GATE APPROVAL
| | | | |
| | v v v
| | +--------------------------------+
| | | ApprovalGateManager |
| | | - create request |
| | | - LangGraph interrupt() |
| | | - notify approvers (SNS) |
| | | - persist state (DynamoDB) |
| | +--------------------------------+
| | |
| | Human decides via interface
| | |
| | +-----+-----+
| | | |
| | APPROVED REJECTED / TIMEOUT
| | | |
v v v v
+--------------------------------+
| Execute or Abort Action |
+--------------------------------+
|
v
+--------------------------------+
| HITLAuditLog (hash chain) |
| Immutable decision record |
+--------------------------------+
|
v
+--------------------------------+
| Feed to Article 8 eval + |
| collaborative edit learning |
+--------------------------------+
Reference Infrastructure Stack
The Reference Infrastructure Stack stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph. Keep graph state flat and typed. Nested blobs hide which node wrote which field and break resume after interrupts.
+-----------------------------+---------------------+------------------------------+
| Component | Technology | Role |
+-----------------------------+---------------------+------------------------------+
| Action Policy Engine | Custom | Per-action approval routing |
| | | based on risk profile |
+-----------------------------+---------------------+------------------------------+
| Pause / Resume | LangGraph interrupt | Durable suspend while |
| | + checkpointing | waiting for human |
+-----------------------------+---------------------+------------------------------+
| Approval Requests | DynamoDB | Pending request state, |
| | | decision records |
+-----------------------------+---------------------+------------------------------+
| Notifications | SNS | Alert approvers when a |
| | | decision is needed |
+-----------------------------+---------------------+------------------------------+
| Escalation | Custom + Haiku | Agent self-assessment of |
| | confidence model | when to hand off to human |
+-----------------------------+---------------------+------------------------------+
| Collaborative Edits | DynamoDB | Draft-edit-finalize flow, |
| | | edit pattern learning |
+-----------------------------+---------------------+------------------------------+
| Oversight Sampling | Custom + DynamoDB | Post-hoc review of a sample |
| | | of autonomous actions |
+-----------------------------+---------------------+------------------------------+
| Timeout Handling | Scheduled Lambda | Policy-defined action on |
| | | expired approval requests |
+-----------------------------+---------------------+------------------------------+
| Audit Trail | DynamoDB hash chain | Immutable, tamper-evident |
| | | record of all decisions |
+-----------------------------+---------------------+------------------------------+
| Auth for Approvers | CredentialManager | Role-based approval |
| | (Article 5) | authorization |
+-----------------------------+---------------------+------------------------------+
| Learning Loop | Article 8 eval | Edits and reviews feed the |
| | pipeline | improvement pipeline |
+-----------------------------+---------------------+------------------------------+
| Local Dev Alternative | Docker Compose + | Full HITL flow testable |
| | mock approver UI | without AWS |
+-----------------------------+---------------------+------------------------------+
Operational checklist
For the Operational checklist stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state.
Prefer small, testable units over sprawling scripts. When a step fails, the failure should point at a single responsibility rather than a tangled pipeline.
Put human approval on edges that spend money or change production data. Compile-time wiring does not equal business completeness.
Write a short runbook: how to rotate keys, how to drain the queue, how to roll back the last ingest.
Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.
Put human approval on edges that spend money or change production data. Compile-time wiring does not equal business completeness.
Before promoting the stack, freeze versions, capture a golden transcript for the critical path, and confirm rollback steps. Shared environments need rate limits, tenancy checks, and a clear owner for secret rotation. Prefer boring reliability over clever one-off demos.
Batch note for c9f5fabd2c2d: keep provider keys out of the repo, set a per-session token ceiling, and store transcripts next to the eval fixtures so later model swaps stay comparable.