hlinor-registry 0.8.0

Governance and security layer for auditable AI agent systems.

Hlinor Agent Registry

Latest: The OpenAI/Hugging Face Sandbox Escape: Why Declarative AI Governance is No Longer Optional - Dev.to article

Open-source registry layer for auditable AI agent systems. Define what your AI agents may do, validate it before execution, and keep the decision auditable — without replacing the framework that runs your agents.

Hlinor Agent Registry is a declarative governance layer for agent systems. It turns action boundaries, policies, approvals, and runtime evidence into reviewable YAML contracts that developers and security teams can understand.

---

⚡ Quickstart (Zero Friction)

Get up and running in 3 simple steps:

1. Install

pip install hlinor-registry

2. Initialize Templates

Generate a ready-to-use registry manifest and agent policy file with safe defaults:

hlinor-registry init

(This creates registry.yaml and my_agent.yaml in your current directory)

3. Compile and Test

Compile your policies into an integrity-checked JSON bundle:

hlinor-registry compile --manifest registry.yaml --output bundle.json

New manifests should declare schema_version, metadata.environment, metadata.bundle_revision, and metadata.policy_revision. The legacy top-level version field remains accepted for migration compatibility.

Test the governance enforcement directly from the CLI:

# Test an allowed action
hlinor-registry check --bundle bundle.json --agent my-agent --action read_database

# Test a blocked action (Fail-closed in action)
hlinor-registry check --bundle bundle.json --agent my-agent --action send_external_email

--resource and --signals-file reach the parts of a bundle a bare action name cannot, so an agent whose permission is scoped to a resource or gated behind a policy can be exercised from the terminal:

hlinor-registry check --bundle bundle.json \
  --agent refund-agent --action refund_payment --resource ticket/1234 \
  --signals-file approval.json

Exit codes are 0 allowed, 1 denied, 2 no decision reached — an unreadable bundle or an unusable signals file is the third, never the second.

For an auditable machine-readable decision, emit JSONL and optionally append the same provenance-aware event to a durable log file:

hlinor-registry check \
  --bundle bundle.json \
  --agent my-agent \
  --action read_database \
  --format jsonl \
  --audit-log logs/governance-decisions.jsonl

Each event includes the decision ID, timestamp, reason code, and SHA-256 digest of the policy bundle used to make the decision. It also binds the decision to a canonical request digest.

For context-rich evaluation, use the immutable request API:

from hlinor_registry import ActionRequest, PolicyChecker

request = ActionRequest(
    agent_id="financial-audit-agent",
    action="read",
    actor_id="service:finance-prod",
    resource="report:quarterly",
    attributes={"classification": "confidential"},
    environment="production",
)
decision = PolicyChecker("bundle.json").evaluate(request)

Configure trust roots and signatures become mandatory. Passing trust_store or trusted_keys upgrades the default signature_policy="auto" to "required". Without that, whether a signature was required would come from metadata.environment inside the bundle being verified — so anyone able to rewrite the deployed file could strip the signature, declare the bundle a development build, and disable authentication.

With no trust roots configured there is nothing to verify against, and unsigned bundles are accepted only when the manifest declares development, test, or local. signature_policy="optional" remains an explicit override for controlled migration.

Sign production bundles

Generate an Ed25519 key pair outside the repository:

openssl genpkey -algorithm ED25519 -out policy-signing-key.pem
openssl pkey \
  -in policy-signing-key.pem \
  -pubout \
  -out policy-signing-key.pub.pem

Never commit the private key. Compile deterministically with an explicit validity window:

hlinor-registry compile \
  --manifest registry.yaml \
  --output bundle.json \
  --signing-key policy-signing-key.pem \
  --key-id prod-policy-2026-01 \
  --issuer hlinor-policy-ci \
  --issued-at 2026-07-26T00:00:00Z \
  --expires-at 2026-08-26T00:00:00Z

Configure the runtime trust root in a deployment-owned file:

{
  "schema_version": "1.0",
  "keys": {
    "prod-policy-2026-01": {
      "algorithm": "Ed25519",
      "public_key_path": "policy-signing-key.pub.pem",
      "issuer": "hlinor-policy-ci"
    }
  }
}

Verify the artifact before deployment:

hlinor-registry verify-bundle \
  --bundle bundle.json \
  --trust-store trust-store.json \
  --signature-policy required \
  --required-issuer hlinor-policy-ci \
  --minimum-bundle-revision 42

The same trust requirements are available through PolicyChecker:

checker = PolicyChecker(
    "bundle.json",
    trust_store="trust-store.json",
    signature_policy="required",
    required_issuer="hlinor-policy-ci",
    minimum_bundle_revision=42,
)

---

🛡️ Use cases

Prevent PII leaks

Keep agents that process sensitive data away from external communication and make the restriction explicit in a reviewed registry file:

id: financial-audit-agent
name: Financial Audit Agent
department: finance
description: Audits internal financial reports.
skills: [read_database, anomaly_detection, generate_report]
validators: [financial-data-validator]
policies: [no-pii-in-logs, read-only-database-access]
allowed_actions: [read, analyze, summarize, generate_pdf_report]
blocked_actions: [send_external_email, delete_records]

The blocklist takes priority over the allowlist:

from hlinor_registry import PolicyChecker

checker = PolicyChecker("bundle.json")
decision = checker.check_action("financial-audit-agent", "send_external_email")

assert decision.denied
# decision.reason_code: ACTION_BLOCKLISTED

Block-list matching ignores case, so no spelling of a blocked name gets through. Allow-list matching is exact, so an approval is never extended to a spelling that was not literally approved. Both directions resolve toward denial, and authoring validation rejects action names that differ only by case.

A policies entry with a compiled typed policy behind it is evaluated at runtime and appears in decision.matched_policy_ids — see Require an approval, evidence, or a failure budget. An entry naming no compiled policy stays declarative context for reviewers, as every entry was before 0.8.0.

Scope an action to the resources it may touch

An action list entry may be a glob over a colon-separated key. The key is the action alone when a request names no resource, and action:resource when it does:

allowed_actions:
  - read:report:quarterly/*
  - classify:ticket:*
blocked_actions:
  - read:report:quarterly/secret*

from hlinor_registry import ActionRequest, PolicyChecker

checker = PolicyChecker("bundle.json")

decision = checker.evaluate(
    ActionRequest(
        agent_id="report-agent",
        action="read",
        resource="report:quarterly/q1",
    )
)
assert decision.allowed
assert decision.matched_pattern == "read:report:quarterly/*"

decision = checker.evaluate(
    ActionRequest(
        agent_id="report-agent",
        action="read",
        resource="report:quarterly/secret-q1",
    )
)
assert decision.denied  # ACTION_BLOCKLISTED
assert decision.matched_pattern == "read:report:quarterly/secret*"

decision.matched_pattern names the entry that produced the decision. Unlike matched_policy_ids it is computed from the comparison that was actually made, so an audit record can say denied by read:report:quarterly/secret* rather than just denied.

The syntax is deliberately tiny. * and ? are the whole vocabulary. There is no **, no character class, no alternation, no regular expression and no negation; hlinor-registry validate rejects all of them with a message saying what to use instead. If a decision needs a condition rather than a name, that belongs in a policy object, not in a pattern.

Two properties are worth knowing before you write one:

• An entry with no wildcard is an exact match. read matches the action read with no resource, and does not match read:report:quarterly. Every action list written before patterns existed decides exactly as it did.
• * crosses :. send:email:* therefore also matches send:email:external:someone. A broad allow pattern grants more than its shape suggests, and only the block list narrows it. hlinor-registry lint says so whenever an allow pattern and a block pattern can match the same request key — decided exactly, not by comparing prefixes — because deleting that block entry would silently widen the agent:

Notes for agent.yaml:
  - 'send:email:*' also covers 'send:email:external:*'; the wildcard crosses
    ':' and only 'blocked_actions' narrows it. Removing the block entry would
    widen what this agent may do.

This is a note, not a failure: lint still exits 0. The syntax has no negation, so "everything under this prefix except that" can only be written as a broad allow plus a block, and rejecting the only available spelling of a common intent would just teach people to skip the linter. Warnings — which do fail — are reserved for a file that says one thing and does another, such as allowed_actions: ["*"] under enforcement_mode: strict.

Block-list matching still ignores case and allow-list matching is still exact, in both directions resolving toward denial. A block entry with no wildcard also covers every resource: blocked_actions: [delete_records] refuses delete_records on anything, which is what it looks like it says.

Require an approval, evidence, or a failure budget

Action lists answer may this agent touch this resource at all. A policy answers the question that comes next: given that it may, what must be true of this particular request. A policy is its own file, compiled into the same bundle, and an agent opts in by naming it:

# refund-requires-approval.yaml
type: policy
id: refund-requires-approval
name: Refund Requires Approval
description: A refund needs a recent approval naming that refund.
enforcement: Enforced by PolicyChecker; the adapter supplies the approval.
kind: requires_approval
trigger:
  - refund_payment:*
requires:
  approver_role: support-lead
  max_age_seconds: 900

# refund-agent.yaml
policies: [refund-requires-approval]
allowed_actions: [refund_payment:ticket/*]

decision = checker.evaluate(
    ActionRequest(
        agent_id="refund-agent",
        action="refund_payment",
        resource="ticket/1234",
        signals={
            "approval": {
                "approver_role": "support-lead",
                "granted_for": "refund_payment:ticket/1234",
                "granted_at": "2026-07-27T11:58:00Z",
            }
        },
    )
)
assert decision.allowed
assert decision.matched_policy_ids == ("refund-requires-approval",)

Without that approval the same request is denied, and decision.policy_detail says which policy refused and what was missing. matched_policy_ids now names the policies that were actually evaluated — it was a reserved, always-empty field until this release.

Three handler kinds ship today:

kind	Reads from signals	Refuses when
requires_approval	approval	no approval, wrong role, approval granted for a different request, or outside the freshness window
requires_evidence	evidence	a required claim type is absent, does not name the request's resource, or is outside the window
failure_threshold	failure_counts	the reported consecutive-failure count reaches max_consecutive_failures

Freshness is a window with two ends. A timestamp older than max_age_seconds is stale; one dated more than 30 seconds ahead of the checker's clock is refused rather than treated as very fresh. bind_to_request and same_resource default to true and must be written as real YAML booleans — 0 or "false" is refused at compile time and by the runtime, so a binding check cannot be switched off by something that merely looks false.

same_resource fails closed: if it is on, the request itself must name a resource. A request with no resource is denied rather than having the comparison skipped.

Two properties hold for all of them:

• Policies only restrict. They run after the allow list has already permitted the action, so a satisfied policy can never re-enable something the block list refuses or the allow list omits. Reading the action lists still tells you the widest thing an agent can do.
• A policy an agent names but that nobody compiled stays declarative, as every policies: entry was before this release. hlinor-registry compile prints the split so the difference is visible before signing:

Agent 'refund-agent' enforces: refund-requires-approval
Agent 'refund-agent' declares but does not enforce: no-customer-pii-in-logs (no compiled policy with that id)

What this does not establish. Signals are asserted by the caller. PolicyChecker runs inside the process it governs and cannot tell whether an approval was really granted. What it enforces is that the action does not proceed unless the obligation is claimed, in a form that is recorded and digested, and that the claim is internally consistent — bound to this request, inside the window, about this resource. Those catch the mistakes that actually happen. They do not stop an adapter that fabricates signals. See Known Limitations.

Block unauthorized actions

Use a strict allowlist for agents that should only perform a narrow set of operations. Everything outside the list is denied by PolicyChecker:

decision = checker.check_action("research-agent", "delete_records")

if decision.denied:
    print(f"Blocked before execution: {decision.reason_code}")

This gives security reviews a concrete answer to the question: “What can this agent do?”

Declare API budgets and rate limits for review

Budget and rate-limit policies sit next to the agent's permitted actions, so a reviewer sees them together. PolicyChecker does not enforce them — see What is enforced at runtime below. Your adapter or preflight check reads them and decides:

id: web-research-agent
name: Web Research Agent
department: marketing
description: Collects competitor information from public sources.
skills: [web_search, scrape_public_website, summarize_text]
validators: [public-source-validator]
policies:
  - max_10_searches_per_hour
  - require_budget_check
  - block_known_malicious_domains
allowed_actions: [search, read_public_url, extract_keywords]
blocked_actions: [login_to_website, submit_forms, call_premium_paid_api]
metadata:
  api_budget_limit_usd: 5.00

The registry makes the constraint visible, versionable, and reviewable instead of burying it inside one agent implementation.

---

⚖️ What is enforced at runtime

The repository ships 22 schemas and a set of governance patterns. Most of them are authoring contracts: they are validated when you compile, and they give reviewers a shared vocabulary. They are not evaluated when an agent asks to do something. Read this table before you rely on any of it.

Concern	Validated at compile time	Enforced by PolicyChecker
Action allow list and block list	yes	yes
Resource scope via action patterns (read:report:*)	yes	yes
Typed policies: approval, evidence, failure threshold	yes	yes
Unknown agent, unknown action	yes	yes
Bundle integrity, signature, issuer, validity window	yes	yes
Rollback floor (minimum_bundle_revision)	—	yes
Enforcement mode (strict / permissive)	yes	yes
Budgets and rate limits	yes	no
Approval levels, as a requires_approval policy	yes	yes
Approval levels, as approval-* schema fields	yes	no
protected-resource-boundary schema	yes	no
Evidence binding, as a requires_evidence policy	yes	yes
Circuit breakers, as a failure_threshold policy	yes	yes
evidence-claim-binding / failure-circuit-breaker schemas	yes	no
Execution context and capability verification	yes	no
Lifecycle modes and transition gates	yes	no
Named policies: entry with no compiled policy behind it	yes	no
Declared capabilities	yes	inventory only

PolicyChecker.evaluate() answers two questions. May this agent perform this action on this resource, according to the compiled allow and block lists of a bundle whose integrity and signature check out? And if it may, do the typed policies the agent declares accept this particular request? Everything in the "no" column is a contract your own code, a preflight step, or a human review has to act on.

The second question is answered from signals the caller supplies. That is a real gate — the action does not proceed unless the obligation is claimed — but it is a gate against omission and mistake, not against a caller that lies.

Capabilities are a third category: compiled into the bundle and readable through checker.capabilities and checker.get_capability_info(), but never consulted by a decision. Use them to inspect what a bundle declares, not to conclude that anything is gated on them.

This is deliberate — an action-name gate is a claim a non-engineer can verify by reading the YAML — but it is easy to over-read a repository this size, so it is stated rather than implied. Progress toward enforcing more of the table is tracked in Known Limitations.

---

🏗️ Architecture

flowchart LR
    A["Developer or security team"] --> B["Explicit registry.yaml manifest"]
    B --> C["hlinor-registry compile"]
    C --> D["Integrity-checked or Ed25519-signed policy bundle"]
    D --> E["Runtime adapter or PolicyChecker"]
    E --> F{"Action permitted?"}
    F -->|Yes| G["Execute tool or skill"]
    F -->|No| H["Block and record decision"]
    E --> I["Execution receipts and audit evidence"]
    I --> J["Review, compliance, and incident response"]

Hlinor sits beside your execution framework. Your agents can continue to run in LangChain, CrewAI, or a custom stack while their action boundaries are compiled from an explicit, inspectable manifest.

Long-lived LangChain tools and @governed functions detect a changed bundle and reload it before the next decision. Deploy new bundles atomically so a running process always observes a complete, digest-verified file.

The compiler writes through a verified temporary file and atomically replaces the destination. Agent and capability namespaces are separate, unknown explicit entity types are rejected, and production manifests reject permissive agents unless the unsafe CLI override is deliberately supplied. A missing type remains compatible with legacy agent files; new files should declare type: agent or type: capability explicitly.

Signed bundles bind the policy payload, digest, issuer, key ID, issuance time, and expiration time to an Ed25519 signature. Runtime trust comes from deployment-configured public keys, never from a key embedded in the bundle. Use a trusted minimum bundle revision to enforce a rollback floor.

---

🆚 Where Hlinor sits

Three different things get called "AI guardrails". They operate on different objects and they compose rather than compete.

Layer	Question it answers	Examples
Content safety	Is this text acceptable to produce or accept?	NeMo Guardrails, Guardrails AI, Llama Guard
Orchestration	What runs next, and with which tool?	LangChain, CrewAI, LangGraph
Action authorization	May this agent perform this action right now, and can we prove what was decided?	Hlinor Registry

Content safety inspects what a model says. Hlinor does not look at text at all. It sits in front of the side effect: the tool call, the transfer, the outbound email.

Why not a general policy engine?

Open Policy Agent and Cedar are the serious comparison, and for a team that already runs one, the honest answer is that they can express everything the current PolicyChecker does. Three things differ.

	OPA / Cedar	Hlinor Registry
Policy language	Rego / Cedar, general-purpose	YAML with a fixed schema, deliberately narrow
Audience	Platform engineers	Whoever signs off on what an agent may do
Distribution	Bundles you assemble and serve	Signed bundle is the product: Ed25519, digest, issuer, validity window, rollback floor
Decision provenance	Build it into your own logging	Every decision carries the bundle digest, request digest, signing key fingerprint, and revision
Runtime coupling	Sidecar, service, or embedded evaluator	One Python object reading one local file

Use OPA or Cedar when you need arbitrary policy logic and already operate the infrastructure. Reach for Hlinor when the reviewable artifact matters more than the expressiveness: when someone has to sign what an agent may do, when an auditor has to be shown which exact policy produced a decision, and when the answer must not depend on a service being reachable.

The narrowness is the point. A PolicyChecker decision is an allowlist and a blocklist over action names, which is a claim a non-engineer can verify by reading the YAML.

Against writing it yourself

Most teams start with a set of if-statements around their tool calls, and that works. What it does not give you is an artifact: something signed, versioned, diffable in review, and identical across the services that run your agents. That, rather than the checking logic, is what this repository is.

Hlinor is not an execution framework. Use it when governance must be explicit, reviewable, and portable across the systems that execute your agents.

---

👥 Who is this for?

• Platform teams building internal agent infrastructure.
• Security and compliance teams reviewing agent capabilities.
• Developers who need a policy boundary before tools cause side effects.
• Teams operating multiple agents across departments or projects.
• Open-source maintainers who want YAML examples and automated validation in CI.

---

📦 Installation

From PyPI

pip install hlinor-registry

The core package requires Python 3.10 or newer, PyYAML, and cryptography for Ed25519 bundle signatures. It does not install LangChain, CrewAI, or another agent framework.

Optional integrations

Hlinor is framework-agnostic. We provide ready-to-use wrappers for popular agent ecosystems:

LangChain

pip install "hlinor-registry[langchain]"

from hlinor_registry.integrations.langchain import GovernedTool

safe_tool = GovernedTool(
    tool=my_langchain_tool,
    agent_id="research-agent",
    bundle_path="./dist/policy-bundle.json",
)

CrewAI

pip install "hlinor-registry[crewai]"

from hlinor_registry.integrations.crewai import GovernedCrewTool

safe_search_tool = GovernedCrewTool(
    executor=my_crewai_tool,
    agent_id="research-agent",
    action_name="search_web",
    bundle_path="./dist/policy-bundle.json",
)

See the integration compatibility matrix and examples/ for complete contracts and runnable examples.

Development dependencies

pip install -e ".[dev]"
pytest

---

💻 CLI Reference

Zero-friction commands:

hlinor-registry --version                          # Show version
hlinor-registry init                               # Generate template registry.yaml and my_agent.yaml
hlinor-registry check --bundle X --agent Y --action Z  # Test an action against a compiled bundle
hlinor-registry explain --bundle X --agent Y --action Z  # Get detailed audit explanation
hlinor-registry check --bundle X --agent Y --action Z --format jsonl --audit-log decisions.jsonl

Exit codes for check and explain:

Code	Meaning
0	A decision was reached and the action is allowed
1	A decision was reached and the action is denied
2	No decision was reached: bad arguments, missing or unreadable bundle, broken trust configuration, or a failed audit-log write

Gate on 1 specifically. Treating every non-zero exit as a denial makes a broken deployment look like working governance.

Core commands:

# Compile an explicit manifest into the integrity-checked runtime bundle
hlinor-registry compile --manifest registry.yaml --output dist/policy-bundle.json

# Explicit unsafe override for controlled migration only
hlinor-registry compile --manifest registry.yaml --output dist/policy-bundle.json \
  --allow-permissive-production

# Validate a registry file
hlinor-registry validate-agent examples/search-agent.yaml

# Validate runtime governance contracts
hlinor-registry validate-execution-context <path>
hlinor-registry validate-action-preflight <path>
hlinor-registry validate-capability <path>
hlinor-registry validate-capability-registration examples/funding_intelligence.yaml
hlinor-registry validate-protected-resource-boundary <path>
hlinor-registry validate-evidence-claim <path>
hlinor-registry validate-circuit-breaker <path>

# Inspect a YAML file without changing it
hlinor-registry inspect <path>

---

📚 Documentation

Models and architecture

• Execution model
• Approval model
• Runtime bindings and execution receipts
• Audit trail
• ActionRequest and decision provenance
• Signed bundles and trust stores
• Integration compatibility
• Control Layer architecture
• Project isolation
• Task workspace
• Department handoff

Governance patterns

• Production action boundary
• Protected resource boundary
• Preflight before a costly action
• Evidence-bound claims
• Capability verification
• Agent lifecycle operating modes

---

🛡️ Trust signals

• Comprehensive automated tests covering compilation, validation, policy enforcement, and CLI commands.
• GitHub Actions runs the test suite on Python 3.10, 3.11, 3.12, and 3.13.
• Pre-commit hooks (ruff, mypy, yamllint) ensure consistent code quality.
• Tagged releases use PyPI Trusted Publishing and verify the exact published package in a clean environment.
• YAML schemas, examples, and governance decisions are designed to be reviewed in pull requests.
• Licensed under Apache-2.0 for broad open-source and commercial use.

---

🤝 Community and support

• Star the repository if it helps your team.
• Report bugs or request features through GitHub Issues.
• Discuss designs and use cases in GitHub Discussions.
• Read CONTRIBUTING.md before opening a pull request.
• Follow the Code of Conduct when participating.

---

🏢 Enterprise

Teams adopting agent governance at scale can contact the HlinorAI team at [e-mail] for architecture guidance, policy design, and integration support.

---

📜 License

Hlinor Agent Registry is available under the Apache License 2.0.

🚀 Contributing

Contributions are welcome. Start with an issue or pull request that explains the governance problem, the proposed registry contract, and how the behavior is tested.

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