Forge Pool

Appearance

Replay & Determinism ​

Forge is designed to make computational execution observable, reproducible, and independently verifiable.

This does not mean that every workload produces identical machine-level execution across heterogeneous hardware.

Instead, Forge defines deterministic behavior through a canonical execution contract, controlled execution policies, and replayable execution evidence.

This document explains what Forge guarantees, what it intentionally does not guarantee, and how replay should be used during system evaluation.

Verification Objective ​

After completing this document you should understand:

  • what deterministic replay means in Forge
  • what constitutes an equivalent execution
  • which execution properties are expected to remain stable
  • which runtime properties may legitimately differ
  • how replay evidence supports independent verification

Prerequisites ​

Before continuing, complete:

Replay assumes you already have a completed execution available for inspection.

Replay Philosophy ​

Replay is not intended to reproduce an identical machine execution.

Its purpose is to reproduce an equivalent computational execution.

Forge evaluates equivalence through observable runtime evidence rather than implementation-specific behavior.

text
Canonical Execution Contract
            │
            ▼
Equivalent Execution
            │
            ▼
Stable Result Surface
            │
            ▼
Independent Verification

Canonical Execution Contract ​

Replay always begins with the execution contract.

Equivalent replay requires that the following remain logically equivalent:

  • operation identity
  • primitive profile
  • canonical arguments
  • execution policy
  • deterministic seed (when supported)

Together these define the computational intent of the execution.

Stable Execution Properties ​

The following properties are expected to remain stable across equivalent replay.

Execution Contract ​

The submitted computational intent should remain unchanged.

This includes:

  • operation
  • profile
  • arguments
  • policy
  • requested artifacts

Result Surface ​

For deterministic workloads, the observable computational result should remain equivalent.

Examples include:

  • statistical summaries
  • ranking order
  • graph propagation outcome
  • optimization result
  • selected candidates

Equivalent does not necessarily imply byte-identical serialization.

It means the observable computational outcome remains consistent with the execution contract.

Replay Evidence ​

Replay metadata should consistently identify the execution as replay-compatible.

Typical replay evidence includes:

  • deterministic seed
  • replay token
  • result hash
  • replay identity
  • execution signature

These fields allow independent comparison between executions.

Variable Execution Properties ​

Some runtime characteristics are intentionally not expected to remain identical.

Examples include:

  • execution duration
  • infrastructure routing
  • worker selection
  • scheduling decisions
  • execution timestamps
  • internal planning order
  • execution identifiers

Differences in these fields do not necessarily indicate incorrect execution.

Equivalent Execution ​

Forge evaluates replay using the concept of equivalent execution.

Two executions are considered equivalent when:

  • they originate from equivalent execution contracts
  • they satisfy the same verification policy
  • they produce equivalent computational results
  • they preserve compatible replay evidence

Equivalent execution is intentionally stronger than "same request" and intentionally weaker than "identical machine execution."

Replay Verification ​

Replay verification compares independent executions rather than individual runtime events.

Recommended verification order:

text
Execution Contract
        │
        ▼
Execution Identity
        │
        ▼
Result Surface
        │
        ▼
Artifacts
        │
        ▼
Replay Metadata

Replay should never begin by comparing execution identifiers.

Execution identifiers are intentionally unique.

Replay Across Execution Surfaces ​

Replay is independent of the execution surface.

Equivalent workloads submitted through:

  • Web Core
  • Studio
  • MCP

should produce equivalent observable execution evidence when the execution contract remains equivalent.

The execution surface is not part of the computational intent.

What Replay Proves ​

Successful replay demonstrates that:

  • the execution contract is reproducible
  • deterministic execution policies were respected
  • equivalent computational results can be obtained
  • replay evidence is sufficient for independent comparison

Replay strengthens confidence in runtime behavior by reducing dependence on a single execution.

What Replay Does Not Prove ​

Replay should not be interpreted as proof of:

  • identical processor instructions
  • identical execution timing
  • identical scheduling decisions
  • identical infrastructure topology
  • identical execution identifiers

These properties are outside the scope of replay verification.

Common Misinterpretations ​

Comparing Execution Identifiers ​

Every execution receives a unique identity.

Different identifiers do not indicate replay failure.

Comparing Infrastructure Behavior ​

Infrastructure routing may legitimately differ between equivalent executions.

Replay verifies computational behavior rather than infrastructure placement.

Expecting Byte-Identical Results ​

Replay validates equivalent computational outcomes.

Equivalent execution should not be confused with byte-for-byte serialization equality unless explicitly guaranteed by the executed capability.

Ignoring the Execution Contract ​

Replay comparison is only meaningful when the underlying execution contract remains equivalent.

Changing arguments, policies, or profiles creates a different workload rather than a replay.

Verification Outcome ​

Successful replay establishes confidence that:

  • the workload can be reproduced
  • equivalent computational behavior is preserved
  • replay evidence is sufficient for independent verification
  • runtime behavior is consistent with the execution contract

Replay therefore strengthens trust through repeatable observation rather than implementation claims.

Next Steps ​

Continue with:

These documents extend replay into artifact analysis, validation boundaries, and capability-specific verification workflows.

Related Documentation ​

Final Principle ​

Replay is not about repeating infrastructure.

Replay is about independently confirming that equivalent computational intent produces equivalent observable execution evidence.

That distinction is fundamental to how Forge defines deterministic verification.

Deterministic execution infrastructure for distributed compute.

Copyright © 2026 Forge Pool