21 — Versioning, release gates & failure modes.

Layerup releases are configuration promotions across a fixed environment ladder, gated by evals, drift, and error budgets. Every plane has a documented failure-mode matrix; failure is a first-class state of the substrate.

21.1 Version domains

Domain	Versioning	Pin location
Ontology	release line + branches (§6)	agent / tool / mapping
Mapping	semver per mapping	tenant config
Tool	semver per signature	agent definition
Prompt	semver hash	agent / tool
Retrieval corpus	snapshot id	tool / agent
Model	id + lineage (§12)	routing policy
Agent	semver per definition	tenant config
Policy	policy version (§16.6)	tenant

21.2 Promotion ladder

Fig. 21.1 — Promotion ladder. Gates run automatically at each step; manual sign-off is required at UAT. Rollback is one operator action.

21.3 Release gate matrix

Gate	Inputs	Pass condition	Block action
Schema	artefact diff vs trunk	semver matches change class (§6.1)	auto-block
Eval	candidate vs baseline	bench ≥ pack.min, regression ≤ pack.max	auto-block
Replay	recent runs sample	verdict-delta within noise band	auto-block · operator override possible with note
Adversarial	probe pack	no regression on probes	auto-block
Drift	trailing window	no ≥ 2σ warn	operator alert · block at 3σ
Error budget	SLO burn-rate	no fast-burn breach	auto-block
Tenant sign-off	UAT outcome	tenant-approved	auto-block
Security review	marking change · scope change	security primary signs	auto-block

21.4 Canary algorithm

Route a small percentage of eligible traffic to the candidate (default 1%).
Observe per-step quality, latency, error budget, and drift sigma in 15-minute windows.
Ramp to 5% → 25% → 100% only if all watched metrics stay within bounds.
Any 2σ deviation pauses the ramp; any 3σ deviation rolls back.
Rollback is content-hash promotion of the prior version; takes effect within one minute.

21.5 Rollback strategy

Every promoted artefact records its predecessor’s content hash; rollback is a one-step re-promotion of the predecessor.
In-flight runs at rollback continue against their pinned versions; no run is mid-air-upgraded.
Rollbacks are typed AuditEvents (config.rollback) on the tenant chain.

21.6 Failure-mode matrix

The platform classifies failures into 16 typed modes. Each mode has a detection rule, a containment path, a fallback, and an audit signature. This list is canonical; tenant-specific modes inherit from these classes.

#	Mode	Detection	Containment	Fallback	Audit
1	Hallucination	verifier rule pack · evidence missing for asserted property	verifier blocks Decision · raises Exception	handoff to reviewer queue	`verify.block.hallucination`
2	Schema mismatch	JSON-Schema validation fails at ingest or tool boundary	route to quarantine queue	typed Exception · operator triage	`data.ingest.schema_drift`
3	Stale data	SoR version observed < current at commit time	refuse commit · re-resolve	re-stage with new pre-image	`action.stale_target`
4	Source-of-record downtime	adapter error rate window · circuit breaker	open breaker · pause adapter	flat-file path or queue retry	`integration.source_down`
5	Ambiguous evidence	conflicting EvidenceSpans on same Property	verifier emits Exception	handoff with rationale	`evidence.ambiguous`
6	Conflicting evidence	cross-document contradiction detected	verifier blocks · Exception	handoff · request operator clarification	`evidence.conflict`
7	Low-confidence extraction	extractor confidence < agent threshold	verifier classifies as warn or block	handoff or alternate extractor	`extract.low_confidence`
8	Model drift	drift sigma breach (§13.4)	demote to shadow / demoted	route via fallback model	`model.drift.breach`
9	Privilege escalation attempt	scope check fails on dispatch	PDP denies · principal flagged	raise security alert · lock if pattern	`policy.deny.privilege_escalation`
10	Unauthorised tool invocation	marking or purpose mismatch	PDP denies	operator alert · audit only	`policy.deny.purpose`
11	Duplicate effect	idempotency-key collision with different payload	refuse second commit · raise Exception	operator review · explicit supersession only	`action.duplicate`
12	Adapter writeback failure	adapter returns error after exhausted retries	action moves to `failed`	compensation or replay after fix	`action.adapter_error`
13	RAG poisoning	retrieved spans inconsistent with ontology types · adversarial probe hit	verifier blocks · corpus quarantined	fallback corpus · re-index	`retrieval.poisoned`
14	Prompt injection	injection-detector classifier on input · canary tokens	refuse to dispatch reasoning step	handoff · reviewer triage	`reasoning.injection`
15	Authority breach	authority predicate fails at PDP or commit	refuse stage / refuse commit	handoff to higher authority	`authority.breach`
16	Audit chain breach	chain verifier finds hash mismatch	seal chain at breach point	start new chain · operator + tenant security incident	`audit.tamper_detected`

21.7 Incident response posture

Severity bands (S0–S3) per failure mode with documented response times.
Tenant security primary notified on S0 / S1 and on any audit-chain breach within 15 minutes.
Postmortems include contributory drift / eval signals and any release that crossed the gate.
Postmortems become typed AuditEvents (incident.summary) on the tenant chain.

21.8 Change freeze

During declared change freezes (tenant-defined windows or platform-declared post-incident windows), promotion is auto-blocked across all domains except security-critical patches. Freeze status is visible on the tenant config dashboard.

Foundations

Ontology

Data Plane

Logic & Reasoning

Models

Action Plane

Security & Governance

Operations

Enterprise

Versioning, Release Gates & Failure Modes

21 — Versioning, release gates & failure modes.

21.1 Version domains

21.2 Promotion ladder

21.3 Release gate matrix

21.4 Canary algorithm

21.5 Rollback strategy

21.6 Failure-mode matrix

21.7 Incident response posture

21.8 Change freeze

​21 — Versioning, release gates & failure modes.

​21.1 Version domains

​21.2 Promotion ladder

​21.3 Release gate matrix

​21.4 Canary algorithm

​21.5 Rollback strategy

​21.6 Failure-mode matrix

​21.7 Incident response posture

​21.8 Change freeze

21 — Versioning, release gates & failure modes.

21.1 Version domains

21.2 Promotion ladder

21.3 Release gate matrix

21.4 Canary algorithm

21.5 Rollback strategy

21.6 Failure-mode matrix

21.7 Incident response posture

21.8 Change freeze