Policy Engine

aura-policy is a pure-Rust crate with no Anchor dependency. It is consumed by aura-core on-chain, by sdk-rs for off-chain pre-validation, and by the devnet smoke binaries. All rule logic, violation codes, and FHE graph specs live here — never duplicated in aura-core or the SDKs.

Entry Points

Evaluation Order (evaluate_transaction)

Rules short-circuit on the first failure. No subsequent rules are evaluated after a violation.

Public Precheck vs Full Evaluation

For confidential proposals, evaluate_public_precheck runs the same rules except steps 3 (per_tx_limit) and 4 (daily_limit). Those are deferred to the FHE circuit. If the precheck passes, a note is added to the trace: "encrypted per-transaction and daily-limit checks deferred to Encrypt".

All 27 ViolationCodes

From programs/aura-policy/src/violations/mod.rs:

PolicyConfig Defaults

From programs/aura-policy/src/config/limits.rs — PolicyConfig::default():

Reputation Scaling

effective_daily_limit_usd is computed as:

effective = daily_limit_usd × multiplier_bps(reputation_score) / 10_000

Default ReputationPolicy:

If no reputation score is provided (None), the base daily_limit_usd is used unchanged.

Time Windows

active_hourly_limit returns daytime_hourly_limit_usd for hours 6–21 UTC and nighttime_hourly_limit_usd for hours 22–5 UTC. The hourly counter (hourly_spent_usd) resets when the current hour changes.

Transaction Types

From programs/aura-policy/src/types/transaction.rs:

Regulatory Flags

compute_regulatory_flags returns a u8 bitmask attached to every PolicyDecision:

Anomaly Detection

When anomaly_config.enabled = true and state.recent_amounts.len() >= min_sample_size, the engine computes a z-score over the recent amounts window:

z_score_bps = (amount - mean) / std_dev × 10_000

If z_score_bps > z_score_threshold_bps, the action is applied:

Policy Templates & Canary Testing

AURA now supports reusable policy templates and safe testing of policy changes through canary deployments.

Policy Templates

Pre-defined or custom policy configurations that can be applied to multiple treasuries:

// Create from scratch or fork a built-in preset
await aura.policy.createTemplate({
  authority: ownerPubkey,
  template: {
    name: "conservative-defi",
    config: { /* full PolicyConfig */ },
    metadata: "Low-risk DeFi strategy with tight limits",
    version: 1,
  },
});

// Apply to treasury
await aura.policy.applyTemplate({
  treasury,
  templateAddress,
});

// Apply with parameterized scaling
await aura.policy.applyTemplateParameterized({
  treasury,
  templateAddress,
  scalingBps: 5000, // 50% of template limits
  limitOverrides: { dailyLimitUsd: 20000 }, // override specific field
});

Built-in presets:

• RiskAverse — Tight limits, narrow time windows, low counterparty risk
• Balanced — Default settings from PolicyConfig
• Aggressive — Wider limits, 24/7 operation, higher risk tolerance
• DeFiOptimized — Protocol-specific tuning for DEX/lending
• Payments — High frequency, low amounts, instant settlement

Canary Deployments

Test a candidate policy against live proposals without enforcing it:

// 1. Start canary with candidate policy
await aura.policy.startCanary({
  treasury,
  candidateConfig: { /* proposed PolicyConfig */ },
  minSampleSize: 100, // must score 100 proposals before promotion
});

// 2. Proposals evaluated against both enforced and candidate policies
// Canary tracks: pass/fail counts, deviation patterns, violation distribution

// 3. Promote if canary performs well
await aura.policy.promoteCanary({ treasury });

// Or discard if results are poor
await aura.policy.discardCanary({ treasury });

Canary scoring:

• Runs in parallel with enforced policy (never blocks proposals)
• Tracks pass rate, false positive rate, deviation score
• Requires minimum sample size before promotion
• Automatically records as new policy version on promotion

Policy Versioning & Rollback

All policy changes create immutable version records:

// Check version history
const versions = await aura.policy.getVersionHistory(treasury);
console.log("Current version:", versions.current);
console.log("Previous versions:", versions.history);

// Rollback to previous version (owner + guardian quorum)
await aura.policy.rollbackToVersion({
  treasury,
  targetVersion: 3, // roll back to version 3
});

Version lifecycle:

• Every configure_policy, apply_policy_template, or promote_canary creates a new version
• Versions are sequentially numbered and immutable
• Rollback requires owner signature + guardian quorum for safety
• Version metadata includes timestamp, author, change summary