acgs-lite 2.6.0

Constitutional AI governance for agents — enforce rules, audit decisions, MACI role separation, formal verification, and 18-framework compliance coverage.

ACGS-Lite: Constitutional AI Governance for Agents

The missing safety layer between your LLM and production.

acgs-lite is a deterministic governance engine for AI agents. Define rules in YAML, enforce them at runtime with MACI role separation, and prove compliance with tamper-evident audit trails. Every action is validated before it executes — violations are blocked, not just logged.

---

🚀 5-Line Quickstart

from acgs_lite import Constitution, GovernedAgent

constitution = Constitution.from_yaml("constitution.yaml")
agent = GovernedAgent(my_llm_agent, constitution=constitution)
result = agent.run("Process this high-risk transaction")

Rules in YAML (constitution.yaml):

constitutional_hash: "608508a9bd224290"
rules:
  - id: no-pii
    pattern: "SSN|social security|passport number"
    severity: CRITICAL
    description: Block PII exposure

  - id: no-destructive
    pattern: "delete|drop table|rm -rf"
    severity: HIGH
    description: Block destructive operations

  - id: require-approval
    pattern: "transfer|payment|wire"
    severity: HIGH
    description: Financial actions require human approval

---

📦 Installation

pip install acgs-lite

With framework integrations:

pip install "acgs-lite[openai]"       # OpenAI
pip install "acgs-lite[anthropic]"    # Anthropic Claude
pip install "acgs-lite[langchain]"    # LangChain / LangGraph
pip install "acgs-lite[mcp]"          # Model Context Protocol server
pip install "acgs-lite[autogen]"      # AutoGen / AG2
pip install "acgs-lite[a2a]"          # Google A2A protocol
pip install "acgs-lite[all]"          # All integrations

---

🛡️ Core Concepts

Governance Engine

The GovernanceEngine sits between your agent and its tools. Every action passes through it before execution. Matching rules block or flag the action; the result is an immutable ValidationResult.

from acgs_lite import Constitution, GovernanceEngine, Rule, Severity

constitution = Constitution.from_rules([
    Rule(id="no-pii", pattern=r"SSN|\bpassport\b", severity=Severity.CRITICAL),
    Rule(id="no-delete", pattern=r"\bdelete\b|\bdrop\b", severity=Severity.HIGH),
])

engine = GovernanceEngine(constitution)
result = engine.validate("summarize the quarterly report", agent_id="analyst-01")

if not result.valid:
    for v in result.violations:
        print(f"[{v.severity}] {v.rule_id}: {v.description}")

MACI — Separation of Powers

MACI prevents a single agent from proposing, validating, and executing the same action:

from acgs_lite import MACIEnforcer, MACIRole

enforcer = MACIEnforcer()

# Assign roles
enforcer.assign(agent_id="planner",   role=MACIRole.PROPOSER)
enforcer.assign(agent_id="reviewer",  role=MACIRole.VALIDATOR)
enforcer.assign(agent_id="executor",  role=MACIRole.EXECUTOR)

# Proposer creates; Validator checks; Executor runs — never the same agent
proposal = enforcer.propose("planner", action="deploy v2.1 to production")
approval = enforcer.validate("reviewer", proposal)
enforcer.execute("executor", approval)

Tamper-Evident Audit Trail

Every governance decision is written to an append-only, SHA-256-chained log:

from acgs_lite import AuditLog

log = AuditLog()
engine = GovernanceEngine(constitution, audit_log=log)

engine.validate("send email to [e-mail]", agent_id="mailer")

for entry in log.entries():
    print(entry.id, entry.valid, entry.constitutional_hash)

# Verify chain integrity
assert log.verify_chain(), "Audit log tampered!"

GovernedAgent — Drop-in Wrapper

from acgs_lite import Constitution, GovernedAgent

@GovernedAgent.decorate(constitution=constitution, agent_id="summarizer")
def summarize(text: str) -> str:
    return my_llm.complete(f"Summarize: {text}")

# Raises ConstitutionalViolationError if text contains violations
result = summarize("Q4 revenue was $4.2M")

---

🌐 Integrations

OpenAI

from acgs_lite.integrations.openai import GovernedOpenAI
from openai import OpenAI

client = GovernedOpenAI(OpenAI(), constitution=constitution)
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Analyze the contract"}],
)

Anthropic Claude

from acgs_lite.integrations.anthropic import GovernedAnthropic
import anthropic

client = GovernedAnthropic(anthropic.Anthropic(), constitution=constitution)
message = client.messages.create(
    model="claude-opus-4-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Review this code"}],
)

LangChain

from acgs_lite.integrations.langchain import GovernanceRunnable
from langchain_openai import ChatOpenAI

governed_llm = GovernanceRunnable(
    ChatOpenAI(model="gpt-4o"),
    constitution=constitution,
)
result = governed_llm.invoke("Translate this document")

MCP Server

Start a governance server that any MCP-compatible agent can query:

acgs serve --host 0.0.0.0 --port 8080

from acgs_lite.integrations.mcp_server import create_mcp_server
app = create_mcp_server(constitution=constitution)

---

📋 Compliance Coverage

ACGS maps governance controls to 18 regulatory frameworks. Run acgs assess to generate a compliance report:

acgs assess --framework eu-ai-act --output report.pdf

Framework	Coverage	Key Controls
EU AI Act (High-Risk)	Art. 9, 10, 13, 14, 17	Risk management, human oversight, transparency
NIST AI RMF	7 / 16 functions	Govern, Map, Measure, Manage
SOC 2 + AI	10 / 16 criteria	CC6, CC7, CC9 trust service criteria
HIPAA + AI	9 / 15 safeguards	PHI detection, access controls, audit controls
GDPR Art. 22	10 / 12 requirements	Automated decision-making, right to explanation
CCPA / CPRA	8 / 10 rights	Opt-out, data minimisation, transparency
ISO 42001	Clause 6, 8, 9, 10	AI management system controls
OWASP LLM Top 10	9 / 10 risks	Prompt injection, insecure output, data poisoning

---

🔬 Advanced: Formal Verification

For the highest-risk scenarios, ACGS supports mathematical proof of safety properties.

Z3 SMT Solver

from acgs_lite.integrations.z3_verifier import Z3ConstraintVerifier

verifier = Z3ConstraintVerifier()
result = verifier.verify(
    action="transfer $50,000 to external account",
    constraints=["amount <= 10000", "recipient in approved_list"],
)
print(result.satisfiable, result.counterexample)

Lean 4 Proof Certificates (Leanstral)

from acgs_lite import LeanstralVerifier

verifier = LeanstralVerifier()  # requires mistralai extra
certificate = await verifier.verify(
    property="∀ action : Action, action.amount ≤ 10000",
    context={"action": "transfer $5,000"},
)
print(certificate.kernel_verified)  # True only if Lean kernel accepted proof
print(certificate.to_audit_dict())  # attach to AuditEntry

---

⚡ Performance

Operation	Latency	Notes
Rule validation (Python)	< 1 ms	Aho-Corasick multi-pattern
Rule validation (Rust)	~560 ns	Optional Rust extension
Engine batch (100 rules)	~2 ms	Parallel severity evaluation
Audit write (JSONL)	~50 µs	Append-only, SHA-256 chained
Compliance report	< 500 ms	18 frameworks, cached

---

🖥️ CLI

# Validate a single action
acgs validate "send email to [e-mail]" --constitution rules.yaml

# Run governance status check
acgs status

# Generate compliance report
acgs assess --framework hipaa --output hipaa_report.pdf

# Audit log inspection
acgs audit --tail 20
acgs audit --verify-chain

# Start MCP governance server
acgs serve --port 8080

# EU AI Act Art. 14(3) kill switch
acgs halt --agent-id agent-01 --reason "anomalous behaviour detected"
acgs resume --agent-id agent-01

---

📖 Documentation

Guide	Description
Quickstart	Up and running in 5 minutes
Architecture	Engine internals, MACI deep dive
Integrations	OpenAI, Anthropic, LangChain, MCP, A2A
Compliance	18-framework regulatory mapping
CLI Reference	Full command reference
Why Governance?	The case for deterministic guardrails
OWASP LLM Top 10	ACGS coverage of each risk
Testing Guide	Testing governed agents

---

🤝 Contributing

We welcome contributions! See CONTRIBUTING.md for guidelines.

git clone https://github.com/dislovelhl/acgs-lite
cd acgs-lite/packages/acgs-lite
pip install -e ".[dev]"
pytest tests/ --import-mode=importlib

---

📄 License

Apache-2.0. See LICENSE for details.

Commercial enterprise licences (SLA, support, air-gapped deployment) available at acgs.ai.

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Constitutional Hash: 608508a9bd224290 — embedded in every validation path.