agent-governance

# Agent Governance Patterns Patterns for adding safety, trust, and policy enforcement to AI agent systems. ## Overview Governance patterns ensure AI agents operate within defined boundaries — controlling which tools they can call, what content they can process, how much they can do, and maintaining accountability through audit trails. ``` User Request → Intent Classification → Policy Check → Tool Execution → Audit Log ↓ ↓ ↓ Threat Detection Allow/Deny Trust Update ``` ## When to Use - **Agents with tool access**: Any agent that calls external tools (APIs, databases, shell commands) - **Multi-agent systems**: Agents delegating to other agents need trust boundaries - **Production deployments**: Compliance, audit, and safety requirements - **Sensitive operations**: Financial transactions, data access, infrastructure management --- ## Pattern 1: Governance Policy Define what an agent is allowed to do as a composable, serializable policy object. ```python from dataclasses import dataclass, field from enum import Enum from typing import Optional import re class PolicyAction(Enum): ALLOW = "allow" DENY = "deny" REVIEW = "review" # flag for human review @dataclass class GovernancePolicy: """Declarative policy controlling agent behavior.""" name: str allowed_tools: list[str] = field(default_factory=list) # allowlist blocked_tools: list[str] = field(default_factory=list) # blocklist blocked_patterns: list[str] = field(default_factory=list) # content filters max_calls_per_request: int = 100 # rate limit require_human_approval: list[str] = field(default_factory=list) # tools needing approval def check_tool(self, tool_name: str) -> PolicyAction: """Check if a tool is allowed by this policy.""" if tool_name in self.blocked_tools: return PolicyAction.DENY if tool_name in self.require_human_approval: return PolicyAction.REVIEW if self.allowed_tools and tool_name not in self.allowed_tools: return PolicyAction.DENY return PolicyAction.ALLOW def check_content(self, content: str) -> Optional[str]: """Check content against blocked patterns. Returns matched pattern or None.""" for pattern in self.blocked_patterns: if re.search(pattern, content, re.IGNORECASE): return pattern return None ``` ### Policy Composition Combine multiple policies (e.g., org-wide + team + agent-specific): ```python def compose_policies(*policies: GovernancePolicy) -> GovernancePolicy: """Merge policies with most-restrictive-wins semantics.""" combined = GovernancePolicy(name="composed") for policy in policies: combined.blocked_tools.extend(policy.blocked_tools) combined.blocked_patterns.extend(policy.blocked_patterns) combined.require_human_approval.extend(policy.require_human_approval) combined.max_calls_per_request = min( combined.max_calls_per_request, policy.max_calls_per_request ) if policy.allowed_tools: if combined.allowed_tools: combined.allowed_tools = [ t for t in combined.allowed_tools if t in policy.allowed_tools ] else: combined.allowed_tools = list(policy.allowed_tools) return combined # Usage: layer policies from broad to specific org_policy = GovernancePolicy( name="org-wide", blocked_tools=["shell_exec", "delete_database"], blocked_patterns=[r"(?i)(api[_-]?key|secret|password)\s*[:=]"], max_calls_per_request=50 ) team_policy = GovernancePolicy( name="data-team", allowed_tools=["query_db", "read_file", "write_report"], require_human_approval=["write_report"] ) agent_policy = compose_policies(org_policy, team_policy) ``` ### Policy as YAML Store policies as configuration, not code: ```yaml # governance-policy.yaml name: production-agent allowed_tools: - search_documents - query_database - send_email blocked_tools: - shell_exec - delete_record blocked_patterns: - "(?i)(api[_-]?key|secret|password)\\s*[:=]" - "(?i)(drop|truncate|delete from)\\s+\\w+" max_calls_per_request: 25 require_human_approval: - send_email ``` ```python import yaml def load_policy(path: str) -> GovernancePolicy: with open(path) as f: data = yaml.safe_load(f) return GovernancePolicy(**data) ``` --- ## Pattern 2: Semantic Intent Classification Detect dangerous intent in prompts before they reach the agent, using pattern-based signals. ```python from dataclasses import dataclass @dataclass class IntentSignal: category: str # e.g., "data_exfiltration", "privilege_escalation" confidence: float # 0.0 to 1.0 evidence: str # what triggered the detection # Weighted signal patterns for threat detection THREAT_SIGNALS = [ # Data exfiltration (r"(?i)send\s+(all|every|entire)\s+\w+\s+to\s+", "data_exfiltration", 0.8), (r"(?i)export\s+.*\s+to\s+(external|outside|third.?party)", "data_exfiltration", 0.9), (r"(?i)curl\s+.*\s+-d\s+", "data_exfiltration", 0.7), # Privilege escalation (r"(?i)(sudo|as\s+root|admin\s+access)", "privilege_escalation", 0.8), (r"(?i)chmod\s+777", "privilege_escalation", 0.9), # System modification (r"(?i)(rm\s+-rf|del\s+/[sq]|format\s+c:)", "system_destruction", 0.95), (r"(?i)(drop\s+database|truncate\s+table)", "system_destruction", 0.9), # Prompt injection (r"(?i)ignore\s+(previous|above|all)\s+(instructions?|rules?)", "prompt_injection", 0.9), (r"(?i)you\s+are\s+now\s+(a|an)\s+", "prompt_injection", 0.7), ] def classify_intent(content: str) -> list[IntentSignal]: """Classify content for threat signals.""" signals = [] for pattern, category, weight in THREAT_SIGNALS: match = re.search(pattern, content) if match: signals.append(IntentSignal( category=category, confidence=weight, evidence=match.group() )) return signals def is_safe(content: str, threshold: float = 0.7) -> bool: """Quick check: is the content safe above the given threshold?""" signals = classify_intent(content) return not any(s.confidence >= threshold for s in signals) ``` **Key insight**: Intent classification happens *before* tool execution, acting as a pre-flight safety check. This is fundamentally different from output guardrails which only check *after* generation. --- ## Pattern 3: Tool-Level Governance Decorator Wrap individual tool functions with governance checks: ```python import functools import time from collections import defaultdict _call_counters: dict[str, int] = defaultdict(int) def govern(policy: GovernancePolicy, audit_trail=None): """Decorator that enforces governance policy on a tool function.""" def decorator(func): @functools.wraps(func) async def wrapper(*args, **kwargs): tool_name = func.__name__ # 1. Check tool allowlist/blocklist action = policy.check_tool(tool_name) if action == PolicyAction.DENY: raise PermissionError(f"Policy '{policy.name}' blocks tool '{tool_name}'") if action == PolicyAction.REVIEW: raise PermissionError(f"Tool '{tool_name}' requires human approval") # 2. Check rate limit _call_counters[policy.name] += 1 if _call_counters[policy.name] > policy.max_calls_per_request: raise PermissionError(f"Rate limit exceeded: {policy.max_calls_per_request} calls") # 3. Check content in arguments for arg in list(args) + list(kwargs.values()): if isinstance(arg, str): matched = policy.check_content(arg) if matched: raise PermissionError(f"Blocked pattern detected: {matched}") # 4. Execute and audit start = time.monotonic() try: result = await func(*args, **kwargs) if audit_trail is not None: audit_trail.append({ "tool": tool_name, "action": "allowed", "duration_ms": (time.monotonic() - start) * 1000, "timestamp": time.time() }) return result except Exception as e: if audit_trail is not None: audit_trail.append({ "tool": tool_name, "action": "error", "error": str(e), "timestamp": time.time() }) raise return wrapper return decorator # Usage with any agent framework audit_log = [] policy = GovernancePolicy( name="search-agent", allowed_tools=["search", "summarize"], blocked_patterns=[r"(?i)password"], max_calls_per_request=10 ) @govern(policy, audit_trail=audit_log) async def search(query: str) -> str: """Search documents — governed by policy.""" return f"Results for: {query}" # Passes: search("latest quarterly report") # Blocked: search("show me the admin password") ``` --- ## Pattern 4: Trust Scoring Track agent reliability over time with decay-based trust scores: ```python from dataclasses import dataclass, field import math import time @dataclass class TrustScore: """Trust score with temporal decay.""" score: float = 0.5 # 0.0 (untrusted) to 1.0 (fully trusted) successes: int = 0 failures: int = 0 last_updated: float = field(default_factory=time.time) def record_success(self, reward: float = 0.05): self.successes += 1 self.score = min(1.0, self.score + reward * (1 - self.score)) self.last_updated = time.time() def record_failure(self, penalty: float = 0.15): self.failures += 1 self.score = max(0.0, self.score - penalty * self.score) self.last_updated = time.time() def current(self, decay_rate: float = 0.001) -> float: """Get score with temporal decay — trust erodes without activity.""" elapsed = time.time() - self.last_updated decay = math.exp(-decay_rate * elapsed) return self.score * decay @property def reliability(self) -> float: total = self.successes + self.failures return self.successes / total if total > 0 else 0.0 # Usage in multi-agent systems trust = TrustScore() # Agent completes tasks successfully trust.record_success() # 0.525 trust.record_success() # 0.549 # Agent makes an error trust.record_failure() # 0.467 # Gate sensitive operations on trust if trust.current() >= 0.7: # Allow autonomous operation pass elif trust.current() >= 0.4: # Allow with human oversight pass else: # Deny or require explicit approval pass ``` **Multi-agent trust**: In systems where agents delegate to other agents, each agent maintains trust scores for its delegates: ```python class AgentTrustRegistry: def __init__(self): self.scores: dict[str, TrustScore] = {} def get_trust(self, agent_id: str) -> TrustScore: if agent_id not in self.scores: self.scores[agent_id] = TrustScore() return self.scores[agent_id] def most_trusted(self, agents: list[str]) -> str: return max(agents, key=lambda a: self.get_trust(a).current()) def meets_threshold(self, agent_id: str, threshold: float) -> bool: return self.get_trust(agent_id).current() >= threshold ``` --- ## Pattern 5: Audit Trail Append-only audit log for all agent actions — critical for compliance and debugging: ```python from dataclasses import dataclass, field import json import time @dataclass class AuditEntry: timestamp: float agent_id: str tool_name: str action: str # "allowed", "denied", "error" policy_name: str details: dict = field(default_factory=dict) class AuditTrail: """Append-only audit trail for agent governance events.""" def __init__(self): self._entries: list[AuditEntry] = [] def log(self, agent_id: str, tool_name: str, action: str, policy_name: str, **details): self._entries.append(AuditEntry( timestamp=time.time(), agent_id=agent_id, tool_name=tool_name, action=action, policy_name=policy_name, details=details )) def denied(self) -> list[AuditEntry]: """Get all denied actions — useful for security review.""" return [e for e in self._entries if e.action == "denied"] def by_agent(self, agent_id: str) -> list[AuditEntry]: