aegis
The Aegis server provides real-time governance policy enforcement for AI agent actions, with dynamic policy management and risk assessment.
evaluate_action: Submit an AI agent action (type, target, parameters, description, agent ID) to receive a governance decision —auto(allow),approve(needs human review), orblock(deny).evaluate_batch: Evaluate multiple actions simultaneously, receiving a decision for each.get_policy: Retrieve the currently active governance policy, including action patterns, targets, risk levels, and approval requirements.update_policy: Hot-reload the governance policy from a YAML string, with changes taking effect immediately — no restart required.check_risk: Perform a lightweight risk assessment for a given action type and target, returning just the risk level and approval requirement.
Offers governance and human-in-the-loop approval gates for multi-agent workflows built using the CrewAI framework.
Enables human approval workflows by sending rich embed messages to Discord for reviewing and gating agent actions.
Integrates with LangChain to wrap agent actions with governance rules, providing a runtime engine for policy evaluation and audit logging.
Provides a middleware layer to monitor, control, and gate actions taken by OpenAI-based agents through policy checks and approval workflows.
Allows the server to govern and audit AI agent actions targeting Salesforce, such as managing CRM contacts or performing data updates.
Facilitates human-in-the-loop approvals by posting action requests to Slack, allowing users to authorize or block agent actions directly from a workspace.
Connects with Telegram to provide an approval interface where humans can approve or reject pending AI agent actions using inline keyboards.
What is Aegis
Every AI agent framework reinvents the same governance primitives — and each one does it slightly differently. Aegis is the abstraction layer that unifies them.
Layer | What it does | Examples |
1. Primitives | A universal contract for every tool call |
|
2. Adapters | Auto-instrument any framework through its own hooks | LangChain callbacks, CrewAI |
3. Governance | Declarative primitives you compose into policy | Prompt injection / PII / leak / toxicity guardrails, RBAC, rate limit, cost budget, drift detection, anomaly scoring, trust delegation, justification gap, selection audit, Merkle audit chain |
4. Lifecycle | One runtime, every stage of agent ops | Scan → Instrument → Policy CI/CD → Runtime → Proxy → Audit |
import aegis
aegis.auto_instrument() # 12 frameworks governed. No other code changes.Redis is to in-memory data structures what Aegis is to agent governance: one library, every primitive, every framework, one API. You don't write a LangChain guardrail and a CrewAI guardrail and an OpenAI guardrail — you write one Policy and every framework inherits it.
Primitives
The contract every adapter maps into. Framework-agnostic by design.
Primitive | Purpose | Module |
| Unified representation of any tool / LLM / HTTP / MCP call across all frameworks |
|
| Tripartite structure — Declared (agent-authored) / Assessed (Aegis-computed) / Chain (delegation) |
|
| Declarative YAML rules: match → risk → approval ( |
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| Policy layer that evaluates 6-dimensional impact vectors, not just tool names |
|
| Deterministic regex checks for injection, PII, prompt leak, toxicity — 2.65ms cold / <1µs warm |
|
| Multi-agent hand-off tracking with monotone trust constraint (non-increasing) |
|
| Tamper-evident append-only log, Merkle-chained, SQLite + JSONL + webhook sinks |
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| Audits what an agent excludes, not just what it picks — detects cosmetic alignment |
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| 6D asymmetric scoring: agents declare impact, Aegis independently assesses, gap triggers escalation |
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| Ed25519-signed chain for long-term compliance evidence |
|
Every governance feature in Aegis — anomaly detection, cost budgets, drift, cascade guards, kill switches — is a composition of these primitives. Read the Concepts guide to see how they fit together.
Frameworks
One API. 12 agent frameworks + 3 protocol-level adapters.
Framework | Hook | Status |
LangChain |
| Stable |
CrewAI |
| Stable |
OpenAI Agents SDK |
| Stable |
OpenAI API |
| Stable |
Anthropic API |
| Stable |
LiteLLM |
| Stable |
Google GenAI |
| Stable |
Google ADK |
| Stable |
Pydantic AI |
| Stable |
LlamaIndex |
| Stable |
Instructor |
| Stable |
DSPy |
| Stable |
MCP | Transport-layer proxy for any MCP server (stdio / HTTP) | Stable |
httpx | Middleware for raw HTTP egress (REST agents, webhooks) | Stable |
Playwright | Browser context instrumentation for browsing agents | Stable |
auto_instrument() detects what's installed and patches only those — no hard dependencies. Custom adapters use the same BaseAdapter interface.
Default Guardrails
Guardrail | Default | What it catches |
Prompt injection | Block | 10 attack categories, 85+ patterns, multi-language (EN/KO/ZH/JA) |
PII detection | Warn | 13 categories (email, credit card, SSN, IBAN, API keys, etc.) |
Prompt leak | Warn | System prompt extraction attempts |
Toxicity | Warn | Harmful, violent, or abusive content |
MCP STDIO injection | Block | JSON-RPC injection, frame concatenation, unicode escape bypass (OX Security advisory) |
Deterministic regex — no LLM calls, no network. 2.65ms cold / <1µs warm per check.
Use Cases
The same primitives, five different entry points. Pick whichever matches your workflow.
1. Runtime protection (most common)
One line. Any framework.
import aegis
aegis.auto_instrument()Or zero code changes — AEGIS_INSTRUMENT=1 python my_agent.py. Injection blocking, PII masking, prompt-leak warnings, audit trail, and policy enforcement become active for every LangChain / CrewAI / OpenAI / Anthropic / LiteLLM / ADK / DSPy / LlamaIndex / Pydantic AI call.
Pydantic AI native capability — no monkey-patching, explicit per-agent control:
from pydantic_ai import Agent
from aegis.contrib.pydantic_ai import AegisCapability
agent = Agent(
"openai:gpt-4o-mini",
capabilities=[AegisCapability.default()], # injection, PII, toxicity, prompt-leak, hallucination
)
result = await agent.run("What is AI governance?")Full Pydantic AI integration guide →
2. Pre-production scanning
Find ungoverned AI calls before they ship.
pip install agent-aegis
aegis scan .Aegis Governance Scan
=====================
Scanned: 47 files in ./src
Found 5 ungoverned tool call(s):
agent.py:12 OpenAI function call with tools= — no governance wrapper [ASI02]
tools.py:8 LangChain @tool "search_db" — no policy check [ASI02]
llm.py:21 LiteLLM litellm.completion() — no governance wrapper [ASI02]
run.py:5 subprocess subprocess.run — direct shell execution [ASI08]
api.py:14 HTTP requests.post — raw HTTP in agent code [ASI07]
Governance Score: D (5 ungoverned call(s))Supports --format json|sarif|suggest, --threshold A-F, .aegisscanignore, and inline # aegis: ignore pragmas. Auto-fix with aegis scan --fix.
3. Policy CI/CD
Security tools protect at runtime. Aegis also manages the policy lifecycle — the same way you test and ship code.
aegis plan current.yaml proposed.yaml --audit-db aegis_audit.db
# Policy Impact Analysis
# Rules: 2 added, 1 removed, 3 modified
# Impact (replayed 1,247 actions):
# 23 actions would change from AUTO → BLOCKaegis test policy.yaml tests.yaml # Run in CI
aegis test policy.yaml --generate # Auto-generate test suite
aegis test new.yaml tests.yaml --regression old.yaml # Regression check# .github/workflows/policy-check.yml
- uses: Acacian/aegis@main
with:
policy: aegis.yaml
tests: tests.yaml
fail-on-regression: trueOr block ungoverned calls at PR time:
- uses: Acacian/aegis@v0.9.5
with:
command: scan
fail-on-ungoverned: true4. Audit & compliance
Every call is logged to a tamper-evident Merkle chain, with mappings to EU AI Act / NIST AI RMF / SOC2 built in.
aegis audit ID Session Action Target Risk Decision Result
1 a1b2c3d4... read crm LOW auto success
2 a1b2c3d4... bulk_update crm HIGH approved success
3 a1b2c3d4... delete crm CRITICAL block blockedSQLite + JSONL + webhook sinks. Ed25519 signing for long-term evidence. See the Compliance guide.
5. Governance server (multi-agent)
Centralized governance for multiple agents. Each agent connects via SDK, server handles policy, guardrails, audit, and compliance.
pip install 'agent-aegis[server]'
aegis-server37 REST endpoints + WebSocket audit streaming + web dashboard. Agents auto-register, send heartbeats, and query policy over HTTP. See Governance Framework Server.
30-Second Start
pip install agent-aegisimport aegis
aegis.auto_instrument()
# All 12 frameworks now governed with default guardrails.Or use a YAML policy for full control:
aegis init # Creates aegis.yaml# aegis.yaml
guardrails:
pii: { enabled: true, action: mask }
injection: { enabled: true, action: block, sensitivity: medium }
policy:
version: "1"
defaults:
risk_level: medium
approval: approve
rules:
- name: read_safe
match: { type: "read*" }
risk_level: low
approval: auto
- name: no_deletes
match: { type: "delete*" }
risk_level: critical
approval: blockInstall Options
pip install agent-aegis # Core (includes auto_instrument for all frameworks)
pip install langchain-aegis # LangChain standalone integration
pip install 'agent-aegis[mcp]' # MCP server + proxy
pip install 'agent-aegis[server]' # REST API + dashboard
pip install 'agent-aegis[all]' # EverythingMCP Proxy — govern any MCP server with zero code changes
{
"mcpServers": {
"filesystem": {
"command": "uvx",
"args": ["--from", "agent-aegis[mcp]", "aegis-mcp-proxy",
"--wrap", "npx", "-y",
"@modelcontextprotocol/server-filesystem", "/home"]
}
}
}Works with Claude Desktop, Cursor, VS Code, Windsurf. STDIO injection protection, tool poisoning detection, rug-pull detection, argument sanitization, policy evaluation, full audit trail.
Governance Framework Server
Run Aegis as a dedicated governance server with REST API, WebSocket streaming, and web dashboard.
pip install 'agent-aegis[server]'
aegis-server --init # Generate aegis-server.yaml
aegis-server # Start server on :800037 REST endpoints covering the full governance lifecycle:
API Group | Endpoints | Purpose |
Core | evaluate, execute, audit, policy | Policy evaluation + execution pipeline |
Agents | register, heartbeat, list, status | Agent lifecycle management |
Guardrails | check, list | Content safety checks |
Policy Versioning | commit, diff, rollback, tag | Git-like policy change management |
Crypto Audit | verify, entries, evidence | Tamper-proof audit chain verification |
Trust & Drift | trust score, drift detection | Per-agent behavioral analysis |
Cost | budget check, reports | LLM cost governance |
Compliance | reports, regulatory gaps | SOC2 / GDPR / EU AI Act reports |
Sessions | list, replay | Session recording + forensic replay |
Connect with the Python SDK (sync or async):
from aegis import AegisClient
with AegisClient("http://localhost:8000", agent_id="my-agent") as client:
result = client.evaluate("delete", "user_data")
# result["risk_level"] == "CRITICAL", result["is_allowed"] == Falsefrom aegis import AsyncAegisClient
async with AsyncAegisClient("http://localhost:8000", agent_id="my-agent") as client:
result = await client.evaluate("read", "reports")Config-driven via aegis-server.yaml — guardrails, webhooks (Slack/PagerDuty), rate limiting, cost budgets, and auth all declarative. See aegis-server.example.yaml.
Why Aegis?
Writing your own | Platform guardrails | Enterprise platforms | Aegis | |
Abstraction level | Per-framework if/else | Single-vendor SDK | Proprietary gateway | Universal primitives across 12 frameworks |
Setup | Days of if/else | Vendor-specific config | Kubernetes + procurement | |
Code changes | Wrap every call | SDK-specific | Months of integration | Zero — auto-instruments |
Policy portability | Rewrite per framework | Locked to ecosystem | Usually single-vendor | One YAML policy, every framework |
Governance primitives | Build from scratch | Subset, vendor-defined | Proprietary | 10+ composable primitives |
Policy CI/CD | None | None | None | |
Audit trail | printf debugging | Platform logs only | Cloud dashboard | SQLite + JSONL + webhooks + Merkle chain |
Compliance | Manual docs | None | Enterprise sales cycle | EU AI Act, NIST, SOC2 built-in |
Cost | Engineering time | Free-to-$$$ | $$$$ + infra | Free (MIT). Forever. |
What Only Aegis Does
Other tools check inputs and outputs. Aegis governs the decision itself — with primitives no other governance runtime exposes.
Capability | What it means | Based on |
Tripartite ActionClaim | Every tool call splits into Declared (agent-authored, untrusted), Assessed (Aegis-computed), and Chain (delegation) fields. The structural separation is what makes cosmetic alignment detectable. | |
Justification Gap | 6-dimensional asymmetric scoring: agents declare impact, Aegis independently assesses it, and | Name "ActionClaim" from COA-MAS (Carvalho); 6D metric + runtime form original |
Selection Governance | Audits what agents exclude, not just what they choose. A model that "helpfully" omits risky options is exerting selection power — Aegis detects this. | |
Monotone Trust Constraint | Delegated agents cannot escalate their own authority. Trust levels must be non-increasing along the chain — violations auto-block. | Lattice-based access control |
Full Lifecycle | Scan (detect) → Instrument (protect) → Policy CI/CD (test) → Runtime (govern) → Proxy (gateway) → Audit (trace). One library, one | — |
CLI
aegis scan ./src/ # Detect ungoverned AI calls
aegis score ./src/ --policy policy.yaml # Governance score (0-100)
aegis init # Generate starter policy
aegis validate policy.yaml # Validate syntax
aegis plan current.yaml proposed.yaml # Preview policy changes
aegis test policy.yaml tests.yaml # Policy regression testing
aegis audit # View audit log
aegis serve policy.yaml # REST API + dashboard
aegis probe policy.yaml # Adversarial policy testing
aegis autopolicy "block deletes" # Natural language → YAMLResearch
Original measurements on public agent trace datasets. Stdlib-only, reproducible in 30 seconds.
The Justification Gap in 14,285 Tau-Bench Tool Calls — Formal definition of the Tripartite ActionClaim with a silent-baseline empirical study. 90.3% approve / 9.7% escalate / 0% block across four model:domain groups. Airline domain exposes ~2× the mean gap of retail. Includes soundness sketches for the three structural invariants and an honest note on the
max-only override limitation discovered during the study.Tool Distribution Drift in 1,960 Tau-Bench Trajectories — Shannon entropy on tool name sequences across GPT-4o and Sonnet 3.5 New. 39.8% of scored trajectories collapse onto one or two tools by the end. Bimodal distribution, 1.7× cross-model gap. All scripts and raw data included.
Run the same signal on your own trace:
aegis check drift --trace path/to/trace.jsonlThe CLI reads only the tool_name field — never args, CoT, or prompts — so enterprise users can score prod traces without exfiltrating PII.
Documentation
Full documentation at acacian.github.io/aegis:
Integration guides — LangChain, CrewAI, OpenAI, MCP, and more
Policy reference — conditions, templates, best practices
Security features — guardrails, anomaly detection, compliance
Architecture — how the codebase is structured
Interactive playground — try in browser, no install
Contributing
git clone https://github.com/Acacian/aegis.git && cd aegis
make dev # Install deps + hooks
make test # Run tests
make lint # Lint + format checkContributing Guide • Good First Issues •
License
MIT -- see LICENSE for details.
Copyright (c) 2026 구동하 (Dongha Koo, @Acacian). Created March 21, 2026.
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