Runtime Concepts
Forge is easier to understand if you follow an execution than if you study individual components.
This guide explains the runtime by following the lifecycle of a single workload—from the moment a question is submitted until its execution becomes durable computational evidence.
After reading this guide you will understand:
- what an execution contract is
- how jobs become shards
- how shards become distributed execution
- how computation becomes execution evidence
- how replay is preserved
- how the Forge runtime is organized
The Runtime Mental Model
Every execution follows the same conceptual lifecycle.
Question
│
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Execution Contract
│
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Job
│
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Shards
│
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Distributed Execution
│
▼
Verification
│
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Deterministic Reduction
│
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Execution Evidence
│
▼
ReplayUnderstanding this flow is significantly more valuable than memorizing individual runtime components.
Everything Begins with an Execution Contract
Every workload submitted to Forge begins as an immutable execution contract.
The execution contract defines:
- what should execute
- which primitive family performs execution
- which profile defines workload semantics
- execution arguments
- execution policy
- seed behavior
- replay requirements
The execution contract becomes the computational identity of the workload.
Every subsequent runtime decision is evaluated relative to this contract.
From Execution Contract to Job
Once accepted by the runtime, the execution contract becomes a Job.
A Job represents one complete distributed execution.
It contains everything required for execution, including:
- execution identity
- workload definition
- execution policy
- billing context
- replay metadata
- execution state
Jobs remain immutable after execution completes.
The Job—not the API request—is the durable execution object.
From Job to Shards
Large computational workloads are partitioned into deterministic shards.
For example:
1,000,000 iterations
│
▼
10 deterministic shards
│
▼
100,000 iterations per shardSharding enables:
- horizontal scalability
- workload isolation
- fault recovery
- heterogeneous scheduling
- verification
- elastic execution
Shard planning is deterministic.
Given the same execution contract, the same shard structure is produced.
From Shards to Distributed Execution
After shard planning completes, execution begins.
Multiple execution agents receive independent shard assignments and execute them in parallel.
Each agent is responsible only for its assigned computational work.
Execution agents never determine global computational truth.
They produce partial computational evidence.
The final result is established elsewhere in the runtime.
The Runtime Architecture
Although execution appears as a single operation, several runtime components cooperate to preserve deterministic execution.
Web Core
│
governs execution
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Kernel
defines execution semantics
│
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Hub
plans and orchestrates execution
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Agents
perform distributed computation
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Reducers
produce computational truthEach component has a distinct responsibility.
No individual component independently defines execution correctness.
Primitive Families
Primitive families define canonical classes of computation.
Examples include:
mc@1tensor@1graph@1search@1media@1ensemble@1
Primitive families describe how computation behaves.
They do not describe business domains.
Profiles
Profiles specialize primitive families into workload-specific execution semantics.
Examples include:
insurance.v1eta.v1matmul.v1transcode.v1
A useful mental model is:
Primitive Family
defines computational class
+
Profile
defines workload semanticsExamples:
tensor@1
+
matmul.v1mc@1
+
insurance.v1media@1
+
transcode.v1Together they define the computational identity of the workload.
Adapters
Applications rarely communicate directly using primitive families.
Instead, they interact through adapters.
Adapters translate domain-specific requests into canonical execution contracts.
For example:
Insurance Risk
│
▼
Adapter
│
▼
mc@1
│
insurance.v1Adapters may:
- validate input
- transform domain payloads
- generate execution contracts
- normalize outputs
Adapters simplify integration.
They do not define execution semantics.
Deterministic Execution
Forge preserves computational determinism rather than operational determinism.
Execution semantics remain stable even when infrastructure changes.
Deterministic execution depends upon:
- immutable execution contracts
- controlled seed discipline
- deterministic shard planning
- deterministic reduction
- replay preservation
These properties make execution reproducible across heterogeneous infrastructure.
Verification
Distributed execution assumes mixed-trust infrastructure.
Verification ensures that execution faithfully followed the documented execution contract.
Depending on execution policy, verification may include:
- redundant execution
- shard validation
- statistical verification
- deterministic reduction
- replay inspection
Verification establishes execution integrity.
It does not establish domain correctness.
Execution Evidence
Forge preserves considerably more than computational output.
Every execution also produces durable execution evidence.
Execution evidence may include:
- execution contract
- replay metadata
- shard structure
- execution metrics
- verification results
- execution artifacts
- aggregation metadata
Execution evidence allows workloads to remain inspectable after computation has completed.
Replay
Replay preserves computational history.
It does not attempt to reproduce identical infrastructure.
Replay reproduces execution according to the original execution contract and execution doctrine.
Replay therefore depends on preserved execution semantics rather than preserved hardware.
Memory Surfaces
Distributed execution frequently spans multiple stages.
Forge exposes persistent execution surfaces including:
- Blob Storage
- KV State
- VMem
- snapshots
- replay artifacts
- execution references
These allow execution systems to maintain state while preserving deterministic execution behavior.
Ledger
Execution also produces economic evidence.
Clients consume computational capacity.
Providers contribute verified computation.
Ledger records preserve:
- execution accounting
- computational contribution
- verification outcomes
- replay references
- billing events
Economic settlement therefore derives from documented execution rather than declared participation.
Runtime Summary
A useful way to understand Forge is:
Execution Contract
│
▼
Job
│
▼
Shards
│
▼
Distributed Execution
│
▼
Verification
│
▼
Deterministic Reduction
│
▼
Execution Evidence
│
▼
Replay
│
▼
Computational TrustEvery runtime component contributes to one stage of this lifecycle.
Together they form a deterministic distributed execution system.
Where to Go Next
Now that you understand the runtime, continue with:
Trust Layer — learn how Forge establishes computational trust through verification, replay, and execution evidence.
Architecture — understand how the runtime implements deterministic execution across distributed infrastructure.
Clients Guide — integrate applications using execution contracts and production APIs.
Providers Guide — contribute execution capacity to the runtime.
Understanding these documents in sequence mirrors the way the runtime itself is designed.
Final Thought
Forge is not organized around servers, APIs, or infrastructure components.
It is organized around execution.
Every component exists for one reason:
To transform an execution contract into reproducible computation, durable execution evidence, and independently verifiable computational truth.
