Beacon Verification Rate Gate

Gate ID: beacon-rate

Enforces minimum beacon verification rate for runtime canary coverage. When enabled, blocks or warns for releases where beacon coverage is insufficient in a required environment.

How It Works

Checks if the target environment requires beacon coverage (configurable per environment)
Reads beacon telemetry data from the policy context
If no beacon data exists, applies the configured missing-beacon action (warn or block)
If beacon count is below the minimum, defers rate enforcement (insufficient sample size)
Compares verification rate against threshold, returns pass, warn, or block

Configuration

{
  "PolicyGates": {
    "BeaconRate": {
      "Enabled": false,
      "BelowThresholdAction": "Warn",
      "MissingBeaconAction": "Warn",
      "MinVerificationRate": 0.8,
      "RequiredEnvironments": ["production"],
      "MinBeaconCount": 10
    }
  }
}

Options

Option	Type	Default	Description
`Enabled`	bool	`false`	Whether the gate is active (opt-in)
`BelowThresholdAction`	enum	`Warn`	Action when rate is below threshold: `Warn` or `Block`
`MissingBeaconAction`	enum	`Warn`	Action when no beacon data exists: `Warn` or `Block`
`MinVerificationRate`	double	`0.8`	Minimum acceptable verification rate (0.0–1.0)
`RequiredEnvironments`	string[]	`["production"]`	Environments requiring beacon coverage
`MinBeaconCount`	int	`10`	Minimum beacons before rate enforcement applies

Context Metadata Keys

The gate reads the following keys from PolicyGateContext.Metadata:

Key	Type	Description
`beacon_verification_rate`	double string	Verification rate (0.0–1.0)
`beacon_verified_count`	int string	Number of verified beacon events

Beacon Verification States

State	Description	Default Behavior
No data	No beacon telemetry available	Depends on `MissingBeaconAction`
Insufficient count	Fewer beacons than `MinBeaconCount`	Rate enforcement deferred (pass with warning)
Below threshold	Rate < `MinVerificationRate`	Depends on `BelowThresholdAction`
Above threshold	Rate >= `MinVerificationRate`	Pass

Example Gate Results

Pass:

Beacon verification rate (95.0%) meets threshold (80.0%)

Pass (environment not required):

Beacon rate not required for environment 'dev'

Pass (insufficient sample):

Beacon count (3) below minimum (10); rate enforcement deferred

Warn (below threshold):

Beacon verification rate (60.0%) is below threshold (warn mode)

Fail (no data, block mode):

No beacon telemetry data available for this artifact

Fail (below threshold, block mode):

Beacon verification rate (60.0%) is below threshold (80.0%)

This gate consumes beacon verification rate data derived from stella.ops/beaconAttestation@v1 predicates. The rate is computed by the Signals beacon pipeline as verified_beacons / expected_beacons over a configurable lookback window.

docs/contracts/beacon-attestation-v1.md — Predicate contract
docs/modules/policy/gates/execution-evidence-gate.md — Companion execution evidence gate

Last updated: 2026-02-19.