> ## Documentation Index
> Fetch the complete documentation index at: https://docs.phylax.systems/llms.txt
> Use this file to discover all available pages before exploring further.

# How to Plan an L2 Integration

> High-level integration path for networks and sequencers adopting the Credible Layer

Plan where the sequencer validates transactions and how it handles failures. Each L2 needs its own coverage and failure policy.

Ethereum block builders should use [For Ethereum Builders](../ethereum-builder-integration).

## Who This Is For

L2 sequencer, infrastructure, and security teams.

## High-Level Flow

```mermaid theme={null}
---
title: Network Integration Flow
---
flowchart LR
  Users[Users + Applications] --> RPC[Network RPC]
  System[Bridge, System, or Delayed Queues] --> Policy[Integration Policy]
  RPC --> Policy
  Policy --> Builder[Block Builder or Sequencer]
  Builder --> Enforcer[Assertion Enforcer]
  Enforcer -->|valid| Block[Block]
  Enforcer -->|invalid| Drop[Dropped]
  Enforcer -.-> Registry[On-Chain Registry]
  Enforcer -.-> DA[Assertion DA]
```

## Integration Surfaces

Networks provide the following integration surfaces:

* **Block-building hook**: the block builder or sequencer queries the Assertion Enforcer before including a transaction
* **Transaction-source policy**: the integration defines how user-submitted, system-originated, bridge-originated, delayed, or forced-inclusion-style transaction paths are validated
* **Result routing**: validation results are routed back into the block-building or sequencing policy that decides whether a candidate transaction can be included
* **Registry access**: the enforcer consumes registry data (indexed from on-chain events) to discover which assertions apply
* **Assertion data access**: the enforcer fetches assertion bytecode from Assertion DA
* **Operational monitoring**: invalidations, assertion status, alerting, and audit-log events are surfaced via the Phylax platform

## Integration Policy Decisions

### Transaction Source Coverage

For each transaction source, record the validation boundary, inclusion rules, timeout behavior, and invalidation metadata. Include bridge, system, delayed, and forced-inclusion transactions.

If a response window exists, define the protocol actions it permits before inclusion.

### Bounded Response Windows

If the design delays an inclusion decision, define the maximum delay and expiry behavior. Specify permitted protocol responses and record every delayed, retried, or released transaction.

### Ingress traffic management

Cache repeated invalid submissions or use short-lived fingerprints and sender budgets. Broader matches need conservative thresholds and expiry times to avoid suppressing legitimate traffic.

## Operational Expectations

* The enforcer runs alongside the block builder and does not change consensus rules
* Validation is deterministic for the same assertion, state, and execution context
* Protocol teams choose whether assertions run in alerting mode or are enforced; networks honor the registry status during validation
* Network operators define continuity behavior for maintenance windows, degraded dependencies, and validation timeouts
* Production integrations keep assertion work bounded through admission review, trigger scoping, runtime limits, and operational monitoring

## Next Steps

> [card] [Architecture Overview](https://docs.phylax.systems/credible/architecture-overview.md)
>
> Detailed system architecture and transaction flow

> [card] [Assertion Enforcer](https://docs.phylax.systems/credible/assertion-enforcer.md)
>
> Sidecar validation flow and enforcement role

> [card] [Trust Model](https://docs.phylax.systems/credible/trust-model.md)
>
> Guarantees, trust boundaries, and operational assumptions

> [card] [Investigate a Rejected Transaction](https://docs.phylax.systems/credible/investigate-rejected-transaction.md)
>
> Review releases, authorize changes, and investigate rejected transactions.


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