Trust Scoring

Score Range

Trust scores range from 0 to 1000.

Components

Trust scores are computed from four weighted signal components:

Component	Weight	Description
Behavioral	40%	Task completion, error rates, operational reliability
Compliance	25%	BASIS policy adherence, rule violations
Identity	20%	Verification strength, authentication signals
Context	15%	Environmental factors, operational context

Component Details

Behavioral (40%): The largest weight reflects that actions speak louder than credentials. Tracks:

• Task completion rates
• Error frequency
• Response quality
• Tool usage patterns

Compliance (25%): Measures adherence to BASIS policies:

• Policy check pass rates
• Violation history
• Audit outcomes

Identity (20%): Strength of entity verification:

• Authentication method
• Credential validity
• Identity attestations

Context (15%): Environmental and situational factors:

• Operating context appropriateness
• Resource usage patterns
• Interaction patterns

Trust Tiers (T0-T7)

Eight tiers provide graduated autonomy levels:

Tier	Name	Score Range	Description	Capabilities
T0	Sandbox	0-199	Restricted testing	Read-only, no external access
T1	Observed	200-349	New or recovering	Limited operations, high oversight
T2	Provisional	350-499	Proving trustworthiness	Basic operations, monitored
T3	Monitored	500-649	Normal operations	Standard tools, logging required
T4	Standard	650-799	Standard operations	Extended tools, reduced oversight
T5	Trusted	800-875	Elevated privileges	Elevated operations, light oversight
T6	Certified	876-950	Verified and audited	Privileged operations
T7	Autonomous	951-1000	Maximum autonomy	Full capabilities, self-governance

Tier Transitions

Promotion occurs when score crosses upward into a new tier:

• Requires sustained positive signals
• May require additional verification at higher tiers
• Emits trust:tier_changed event with direction: 'promoted'

Demotion occurs when score drops below tier minimum:

• Immediate capability revocation
• Requires recovery to regain privileges
• Emits trust:tier_changed event with direction: 'demoted'

Signal Impacts

Trust scores change based on behavioral signals:

Signal Type	Impact	Notes
task_completed	+5	Standard positive signal
task_failed	-15	3x amplification for failures
policy_violation	-50	Serious compliance breach
compliance_check_passed	+2	Periodic verification
human_endorsement	+25	Explicit trust delegation

Trust Decay

Inactive agents experience trust decay to prevent stale high-trust entities. The decay model uses exponential decay with configurable parameters.

Decay Formula

decayed_score = current_score × (1 - decay_rate)^periods

Where:

• decay_rate: Percentage decay per interval (default: 1%)
• periods: Number of decay intervals elapsed

Default Configuration

Parameter	Default	Description
decayRate	0.01 (1%)	Decay per interval
decayIntervalMs	60000 (1 min)	Interval between decay checks
Signal half-life	7 days	Weight decay for old signals

Accelerated Decay

When an entity accumulates failures, decay accelerates:

Parameter	Default	Description
failureThreshold	0.3	Signals below this are failures
acceleratedDecayMultiplier	3.0	Multiplier when accelerated
failureWindowMs	3600000 (1 hr)	Window for counting failures
minFailuresForAcceleration	2	Failures needed to trigger

Example: With 2+ failures in the past hour, decay rate becomes 3% per interval instead of 1%.

Recovery

Entities can recover trust through positive signals:

Parameter	Default	Description
successThreshold	0.7	Signals above this trigger recovery
recoveryRate	0.02 (2%)	Base recovery per success
acceleratedRecoveryMultiplier	1.5	Multiplier after consecutive successes
minSuccessesForAcceleration	3	Successes needed for acceleration
maxRecoveryPerSignal	50	Maximum points per recovery signal

Activity Reset: Any signal (positive or negative) resets the decay timer.

Configuration Example

import { createTrustEngine } from '@vorionsys/atsf-core/trust-engine';

const engine = createTrustEngine({
  decayRate: 0.005,           // 0.5% per interval (slower decay)
  decayIntervalMs: 300000,    // 5 minutes
  failureThreshold: 0.25,     // Stricter failure detection
  acceleratedDecayMultiplier: 2.0, // Less aggressive acceleration
  recoveryRate: 0.03,         // Faster recovery
});

Initial State

All entities initialize at score 0 (Sandbox tier) unless explicitly promoted by authorized administrator.

Requirements

REQ-TRS-001: Trust scores MUST be computed from defined components.

REQ-TRS-002: Trust checks MUST occur before capability grants.

REQ-TRS-003: Trust score changes >50 points MUST be anchored.

REQ-TRS-004: Trust decay MUST apply to inactive entities.

REQ-TRS-005: Signal impacts MUST be configurable per deployment.