reflex

Attested. A fixture written in AXON is compiled and executed by a gate in the test suite, so this page describes behaviour a test exercises.

Since v1.14.0 · Top-level declaration

Grammar

reflex <Name> {
    trigger: <ImmuneRef>                                          # required — bound immune
    on_level: <know|believe|speculate|doubt>                       # required — firing threshold
    action: <drop|revoke|emit|redact|quarantine|terminate|alert>   # required — closed-catalog action
    scope: <tenant|flow|global>                                    # required — isolation scope
    sla: <duration>                                                # optional — response-time SLA
}

reflex declares an automatic-response trigger bound to an immune system's epistemic-level signal. Where immune detects + emits epistemic signals (know/believe/speculate/doubt), reflex declares what happens automatically when a signal at the bound level fires.

Reflexes are the immediate response layer — no human in the loop, no review queue. They execute the declared action within the declared SLA. For supervised recovery, see heal.

Surface

reflex is a top-level declaration. It is not nested inside an immune or heal.

reflex QuarantineExfil {
    trigger:  ClinicalVigil
    on_level: speculate
    action:   quarantine
    scope:    tenant
    sla:      1ms
}

Fields

trigger: (required)

A single identifier referencing a declared immune. The reflex subscribes to that immune's signal stream.

on_level: (required)

A single identifier from the closed epistemic-level catalogue (axon-frontend::type_checker::VALID_EPISTEMIC_LEVELS):

Value	Fires on
doubt	Faintest signal — fires aggressively (many false positives).
speculate	Possible anomaly — typical for fast-response reflexes.
believe	Likely anomaly — moderate threshold.
know	Clear anomaly — fires rarely, low false-positive rate.

The reflex fires when the immune's signal level matches the declared value or exceeds it. A reflex on believe also fires on know; a reflex on doubt fires on every level.

action: (required)

A single identifier from the closed action catalogue:

Value	Behaviour
drop	Discard the offending input/output silently.
revoke	Revoke the bound capability / token.
emit	Emit a structured signal to the observability layer.
redact	Apply the bound redactor before continuing.
quarantine	Route the offending payload to the quarantine sink.
terminate	Halt the current flow / agent / daemon.
alert	Page the on-call channel.

The parser rejects unknown values.

scope: (required)

A single identifier from the closed scope catalogue: tenant | flow | global. Determines the blast radius of the action — tenant actions affect only the originating tenant; global actions affect the deployment.

sla: (optional)

A duration literal declaring the response-time SLA. Production reflexes typically declare sub-millisecond to single-second SLAs — anything slower is operationally a heal, not a reflex.

The runtime measures actual response time and emits axon-W016 if a reflex consistently breaches its SLA.

Runtime behaviour

reflex lowers to a ReflexDefinition IR node. The v1.14.0 supervisor binds the reflex to its trigger immune:

1. Subscribe to the immune's signal stream.
2. Filter signals at the on_level: threshold.
3. Per matching signal, run action: within the declared scope: and SLA.
4. Audit row reflex:<name>:fired:<level>:<action> carries (trigger_event, latency, action_outcome).

For action: terminate, the runtime terminates the specifically-scoped target (the flow / agent / daemon that produced the offending observation) — NOT the entire deployment.

What this primitive is NOT

• Not a heal. Heal is the supervised recovery counterpart (human-in-the-loop, longer SLA, structured remediation). Reflex is the immediate automatic response.
• Not an anchor. Anchor is a per-emission predicate; reflex is a continuous signal-listener bound to an immune.
• Not a shield. Shield runs in-band on emissions; reflex fires on the immune's epistemic-signal stream (asynchronous).
• Not a notification mechanism. Reflex performs an ACTION (drop / revoke / quarantine / terminate). For notifications, use action: alert or pair the reflex with an observability sink.

See also

• axon://primitives/immune — the trigger source.
• axon://primitives/heal — supervised-recovery counterpart.
• axon://primitives/shield — in-band defence counterpart.
• axon://compliance/hipaa — example reflex on PHI exfiltration with action: quarantine + scope: tenant.